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12020-11-11 version 3.14.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
2
3  Protocol Compiler
4  * The proto compiler no longer requires a .proto filename when it is not
5    generating code.
6  * Added flag `--deterministic_output` to `protoc --encode=...`.
7  * Fixed deadlock when using google.protobuf.Any embedded in aggregate options.
8
9  C++
10  * Arenas are now unconditionally enabled. cc_enable_arenas no longer has
11    any effect.
12  * Removed inlined string support, which is incompatible with arenas.
13  * Fix a memory corruption bug in reflection when mixing optional and
14    non-optional fields.
15  * Make SpaceUsed() calculation more thorough for map fields.
16  * Add stack overflow protection for text format with unknown field values.
17  * FieldPath::FollowAll() now returns a bool to signal if an out-of-bounds
18    error was encountered.
19  * Performance improvements for Map.
20  * Minor formatting fix when dumping a descriptor to .proto format with
21    DebugString.
22  * UBSAN fix in RepeatedField (#2073).
23  * When running under ASAN, skip a test that makes huge allocations.
24  * Fixed a crash that could happen when creating more than 256 extensions in
25    a single message.
26  * Fix a crash in BuildFile when passing in invalid descriptor proto.
27  * Parser security fix when operating with CodedInputStream.
28  * Warn against the use of AllowUnknownExtension.
29  * Migrated to C++11 for-range loops instead of index-based loops where
30    possible. This fixes a lot of warnings when compiling with -Wsign-compare.
31  * Fix segment fault for proto3 optional (#7805)
32  * Adds a CMake option to build `libprotoc` separately (#7949)
33
34  Java
35  * Bugfix in mergeFrom() when a oneof has multiple message fields.
36  * Fix RopeByteString.RopeInputStream.read() returning -1 when told to read
37    0 bytes when not at EOF.
38  * Redefine remove(Object) on primitive repeated field Lists to avoid
39    autoboxing.
40  * Support "\u" escapes in textformat string literals.
41  * Trailing empty spaces are no longer ignored for FieldMask.
42  * Fix FieldMaskUtil.subtract to recursively remove mask.
43  * Mark enums with `@java.lang.Deprecated` if the proto enum has option
44    `deprecated = true;`.
45  * Adding forgotten duration.proto to the lite library (#7738)
46
47  Python
48  * Print google.protobuf.NullValue as null instead of "NULL_VALUE" when it is
49    used outside WKT Value/Struct.
50  * Fix bug occurring when attempting to deep copy an enum type in python 3.
51  * Add a setuptools extension for generating Python protobufs (#7783)
52  * Remove uses of pkg_resources in non-namespace packages. (#7902)
53  * [bazel/py] Omit google/__init__.py from the Protobuf runtime. (#7908)
54  * Removed the unnecessary setuptools package dependency for Python package (#7511)
55  * Fix PyUnknownFields memory leak (#7928)
56
57  PHP
58  * Added support for "==" to the PHP C extension (#7883)
59  * Added `==` operators for Map and Array. (#7900)
60  * Native C well-known types (#7944)
61  * Optimized away hex2bin() call in generated code (#8006)
62  * New version of upb, and a new hash function wyhash in third_party. (#8000)
63  * add missing hasOneof method to check presence of oneof fields (#8003)
64
65  Go:
66  * Update go_package options to reference google.golang.org/protobuf module.
67
68  C#:
69  * annotate ByteString.CopyFrom(ReadOnlySpan<byte>) as SecuritySafeCritical (#7701)
70  * Fix C# optional field reflection when there are regular fields too (#7705)
71  * Fix parsing negative Int32Value that crosses segment boundary (#8035)
72
73  Javascript:
74  * JS: parse (un)packed fields conditionally (#7379)
75
762020-07-14 version 3.13.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
77
78  PHP:
79  * The C extension is completely rewritten. The new C extension has significantly
80    better parsing performance and fixes a handful of conformance issues. It will
81    also make it easier to add support for more features like proto2 and proto3 presence.
82  * The new C extension does not support PHP 5.x. PHP 5.x users can still use pure-PHP.
83
84  C++:
85  * Removed deprecated unsafe arena string accessors
86  * Enabled heterogeneous lookup for std::string keys in maps.
87  * Removed implicit conversion from StringPiece to std::string
88  * Fix use-after-destroy bug when the Map is allocated in the arena.
89  * Improved the randomness of map ordering
90  * Added stack overflow protection for text format with unknown fields
91  * Use std::hash for proto maps to help with portability.
92  * Added more Windows macros to proto whitelist.
93  * Arena constructors for map entry messages are now marked "explicit"
94    (for regular messages they were already explicit).
95  * Fix subtle aliasing bug in RepeatedField::Add
96  * Fix mismatch between MapEntry ByteSize and Serialize with respect to unset
97    fields.
98
99  Python:
100  * JSON format conformance fixes:
101    * Reject lowercase t for Timestamp json format.
102    * Print full_name directly for extensions (no camelCase).
103    * Reject boolean values for integer fields.
104    * Reject NaN, Infinity, -Infinity that is not quoted.
105    * Base64 fixes for bytes fields: accept URL-safe base64 and missing padding.
106  * Bugfix for fields/files named "async" or "await".
107  * Improved the error message when AttributeError is returned from __getattr__
108    in EnumTypeWrapper.
109
110  Java:
111  * Fixed a bug where setting optional proto3 enums with setFooValue() would
112    not mark the value as present.
113  * Add Subtract function to FieldMaskUtil.
114
115  C#:
116  * Dropped support for netstandard1.0 (replaced by support for netstandard1.1).
117    This was required to modernize the parsing stack to use the `Span<byte>`
118    type internally. (#7351)
119  * Add `ParseFrom(ReadOnlySequence<byte>)` method to enable GC friendly
120    parsing with reduced allocations and buffer copies. (#7351)
121  * Add support for serialization directly to a `IBufferWriter<byte>` or
122    to a `Span<byte>` to enable GC friendly serialization.
123    The new API is available as extension methods on the `IMessage` type. (#7576)
124  * Add `GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE` define to make
125    generated code compatible with old C# compilers (pre-roslyn compilers
126    from .NET framework and old versions of mono) that do not support
127    ref structs. Users that are still on a legacy stack that does
128    not support C# 7.2 compiler might need to use the new define
129    in their projects to be able to build the newly generated code. (#7490)
130  * Due to the major overhaul of parsing and serialization internals (#7351 and #7576),
131    it is recommended to regenerate your generated code to achieve the best
132    performance (the legacy generated code will still work, but might incur
133    a slight performance penalty).
134
1352020-07-28 version 3.12.4 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
136
137This release contains no significant changes, but exists because 3.12.3 was
138mistakenly tagged at the wrong commit.
139
1402020-06-01 version 3.12.3 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
141
142  Objective-C
143  * Tweak the union used for Extensions to support old generated code. #7573
144
1452020-05-26 version 3.12.2 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
146
147  C++
148  * Simplified the template export macros to fix the build for mingw32. (#7539)
149
150  Objective-C
151  * Fix for the :protobuf_objc target in the Bazel BUILD file. (#7538)
152
1532020-05-20 version 3.12.1 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
154
155  Ruby
156  * Re-add binary gems for Ruby 2.3 and 2.4. These are EOL upstream, however
157    many people still use them and dropping support will require more
158    coordination.
159
1602020-05-12 version 3.12.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
161
162  Protocol Compiler
163  * [experimental] Singular, non-message typed fields in proto3 now support
164    presence tracking. This is enabled by adding the "optional" field label and
165    passing the --experimental_allow_proto3_optional flag to protoc.
166    * For usage info, see docs/field_presence.md.
167    * During this experimental phase, code generators should update to support
168      proto3 presence, see docs/implementing_proto3_presence.md for instructions.
169  * Allow duplicate symbol names when multiple descriptor sets are passed on
170    the command-line, to match the behavior when multiple .proto files are passed.
171  * Deterministic `protoc --descriptor_set_out` (#7175)
172
173  C++
174  * [experimental] Added proto3 presence support.
175  * New descriptor APIs to support proto3 presence.
176  * Enable Arenas by default on all .proto files.
177  * Documented that users are not allowed to subclass Message or MessageLite.
178  * Mark generated classes as final; inheriting from protos is strongly discouraged.
179  * Add stack overflow protection for text format with unknown fields.
180  * Add accessors for map key and value FieldDescriptors.
181  * Add FieldMaskUtil::FromFieldNumbers().
182  * MessageDifferencer: use ParsePartial() on Any fields so the diff does not
183    fail when there are missing required fields.
184  * ReflectionOps::Merge(): lookup messages in the right factory, if it can.
185  * Added Descriptor::WellKnownTypes enum and Descriptor::well_known_type()
186    accessor as an easier way of determining if a message is a Well-Known Type.
187  * Optimized RepeatedField::Add() when it is used in a loop.
188  * Made proto move/swap more efficient.
189  * De-virtualize the GetArena() method in MessageLite.
190  * Improves performance of json_stream_parser.cc by factor 1000 (#7230)
191  * bug: #7076 undefine Windows OUT and OPTIONAL macros (#7087)
192  * Fixed a bug in FieldDescriptor::DebugString() that would erroneously print
193    an "optional" label for a field in a oneof.
194  * Fix bug in parsing bool extensions that assumed they are always 1 byte.
195  * Fix off-by-one error in FieldOptions::ByteSize() when extensions are present.
196  * Clarified the comments to show an example of the difference between
197    Descriptor::extension and DescriptorPool::FindAllExtensions.
198  * Add a compiler option 'code_size' to force optimize_for=code_size on all
199    protos where this is possible.
200
201  Java
202  * [experimental] Added proto3 presence support.
203  * Mark java enum _VALUE constants as @Deprecated if the enum field is deprecated
204  * reduce <clinit> size for enums with allow_alias set to true.
205  * Sort map fields alphabetically by the field's key when printing textproto.
206  * Fixed a bug in map sorting that appeared in -rc1 and -rc2 (#7508).
207  * TextFormat.merge() handles Any as top level type.
208  * Throw a descriptive IllegalArgumentException when calling
209    getValueDescriptor() on enum special value UNRECOGNIZED instead of
210    ArrayIndexOutOfBoundsException.
211  * Fixed an issue with JsonFormat.printer() where setting printingEnumsAsInts()
212    would override the configuration passed into includingDefaultValueFields().
213  * Implement overrides of indexOf() and contains() on primitive lists returned
214    for repeated fields to avoid autoboxing the list contents.
215  * Add overload to FieldMaskUtil.fromStringList that accepts a descriptor.
216  * [bazel] Move Java runtime/toolchains into //java (#7190)
217
218  Python
219  * [experimental] Added proto3 presence support.
220  * [experimental] fast import protobuf module, only works with cpp generated code linked in.
221  * Truncate 'float' fields to 4 bytes of precision in setters for pure-Python
222    implementation (C++ extension was already doing this).
223  * Fixed a memory leak in C++ bindings.
224  * Added a deprecation warning when code tries to create Descriptor objects
225    directly.
226  * Fix unintended comparison between bytes and string in descriptor.py.
227  * Avoid printing excess digits for float fields in TextFormat.
228  * Remove Python 2.5 syntax compatibility from the proto compiler generated _pb2.py module code.
229  * Drop 3.3, 3.4 and use single version docker images for all python tests (#7396)
230
231  JavaScript
232  * Fix js message pivot selection (#6813)
233
234  PHP
235  * Persistent Descriptor Pool (#6899)
236  * Implement lazy loading of php class for proto messages (#6911)
237  * Correct @return in Any.unpack docblock (#7089)
238  * Ignore unknown enum value when ignore_unknown specified (#7455)
239
240  Ruby
241  * [experimental] Implemented proto3 presence for Ruby. (#7406)
242  * Stop building binary gems for ruby <2.5 (#7453)
243  * Fix for wrappers with a zero value (#7195)
244  * Fix for JSON serialization of 0/empty-valued wrapper types (#7198)
245  * Call "Class#new" over rb_class_new_instance in decoding (#7352)
246  * Build extensions for Ruby 2.7 (#7027)
247  * assigning 'nil' to submessage should clear the field. (#7397)
248
249  C#
250  * [experimental] Add support for proto3 presence fields in C# (#7382)
251  * Mark GetOption API as obsolete and expose the "GetOptions()" method on descriptors instead (#7491)
252  * Remove Has/Clear members for C# message fields in proto2 (#7429)
253  * Enforce recursion depth checking for unknown fields (#7132)
254  * Fix conformance test failures for Google.Protobuf (#6910)
255  * Cleanup various bits of Google.Protobuf (#6674)
256  * Fix latest ArgumentException for C# extensions (#6938)
257  * Remove unnecessary branch from ReadTag (#7289)
258
259  Objective-C
260  * [experimental] ObjC Proto3 optional support (#7421)
261  * Block subclassing of generated classes (#7124)
262  * Use references to Obj C classes instead of names in descriptors. (#7026)
263  * Revisit how the WKTs are bundled with ObjC. (#7173)
264
265  Other
266  * Add a proto_lang_toolchain for javalite (#6882)
267  * [bazel] Update gtest and deprecate //external:{gtest,gtest_main} (#7237)
268  * Add application note for explicit presence tracking. (#7390)
269  * Howto doc for implementing proto3 presence in a code generator. (#7407)
270
271
2722020-02-14 version 3.11.4 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
273
274  C#
275  * Fix latest ArgumentException for C# extensions (#7188)
276  * Enforce recursion depth checking for unknown fields (#7210)
277
278  Ruby
279  * Fix wrappers with a zero value (#7195)
280  * Fix JSON serialization of 0/empty-valued wrapper types (#7198)
281
2822020-01-31 version 3.11.3 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
283
284  C++
285  * Add OUT and OPTIONAL to windows portability files (#7087)
286
287  PHP
288  * Refactored ulong to zend_ulong for php7.4 compatibility (#7147)
289  * Call register_class before getClass from desc to fix segfault (#7077)
290
291
2922019-12-10 version 3.11.2 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
293
294  PHP
295  * Make c extension portable for php 7.4 (#6968)
296
297
2982019-12-02 version 3.11.1 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
299
300  PHP
301  * Extern declare protobuf_globals (#6946)
302
303
3042019-11-19 version 3.11.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
305
306  C++
307  * Make serialization method naming consistent
308  * Make proto runtime + generated code free of deprecation warnings
309  * Moved ShutdownProtobufLibrary() to message_lite.h.  For backward compatibility a declaration is still available in stubs/common.h, but users should prefer message_lite.h
310  * Removed non-namespace macro EXPECT_OK()
311  * Removed mathlimits.h from stubs in favor of using std::numeric_limits from C++11
312  * Fixed bug in parser when ending on a group tag
313  * Add a helper function to UnknownFieldSet to deal with the changing return value of message::unknown_fields()
314  * Fix incorrect use of string_view iterators
315  * Support direct pickling of nested messages
316  * Skip extension tag validation for MessageSet if unknown dependencies are allowed
317  * Updated deprecation macros to annotate deprecated code (#6612)
318  * Remove conversion warning in MapEntryFuncs::ByteSizeLong (#6766)
319  * Revert "Make shared libraries be able to link to MSVC static runtime libraries, so that VC runtime is not required." (#6914)
320
321  Java
322  * Remove the usage of MethodHandle, so that Android users prior to API version 26 can use protobuf-java
323  * Publish ProGuard config for javalite
324  * Fix for StrictMode disk read violation in ExtensionRegistryLite
325  * Include part of the ByteString's content in its toString().
326  * Include unknown fields when merging proto3 messages in Java lite builders
327
328  Python
329  * Add float_precision option in json format printer
330  * Optionally print bytes fields as messages in unknown fields, if possible
331  * FieldPath: fix testing IsSet on root path ''
332  * Experimental code gen (fast import protobuf module) which only work with cpp generated code linked in
333
334  JavaScript
335  * Remove guard for Symbol iterator for jspb.Map
336
337  PHP
338  * Avoid too much overhead in layout_init (#6716)
339  * Lazily Create Singular Wrapper Message (#6833)
340  * Implement lazy loading of php class for proto messages (#6911)
341
342  Ruby
343  * Ruby lazy wrappers optimization (#6797)
344
345  C#
346  * (RepeatedField): Capacity property to resize the internal array (#6530)
347  * Experimental proto2 support is now officially available (#4642, #5183, #5350, #5936)
348  * Getting started doc: https://github.com/protocolbuffers/protobuf/blob/master/docs/csharp/proto2.md
349  * Add length checks to ExtensionCollection (#6759)
350  * Optimize parsing of some primitive and wrapper types (#6843)
351  * Use 3 parameter Encoding.GetString for default string values (#6828)
352  * Change _Extensions property to normal body rather than expression (#6856)
353
354  Objective C
355  * Fixed unaligned reads for 32bit arm with newer Xcode versions (#6678)
356
357
3582019-09-03 version 3.10.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
359
360  C++
361  * Switch the proto parser to the faster MOMI parser.
362  * Properly escape Struct keys in the proto3 JSON serializer.
363  * Fix crash on uninitialized map entries.
364  * Informed the compiler of has-bit invariant to produce better code
365  * Unused imports of files defining descriptor extensions will now be reported
366  * Add proto2::util::RemoveSubranges to remove multiple subranges in linear time.
367  * Added BaseTextGenerator::GetCurrentIndentationSize()
368  * Made implicit weak fields compatible with the Apple linker
369  * Support 32 bit values for ProtoStreamObjectWriter to Struct.
370  * Removed the internal-only header coded_stream_inl.h and the internal-only methods defined there.
371  * Enforced no SWIG wrapping of descriptor_database.h (other headers already had this restriction).
372  * Implementation of the equivalent of the MOMI parser for serialization. This removes one of the two serialization routines, by making the fast array serialization routine completely general. SerializeToCodedStream can now be implemented in terms of the much much faster array serialization. The array serialization regresses slightly, but when array serialization is not possible this wins big.
373  * Do not convert unknown field name to snake case to accurately report error.
374  * Fix a UBSAN warnings. (#6333)
375  * Add podspec for C++ (#6404)
376  * protoc: fix source code info location for missing label (#6436)
377  * C++ Add move constructor for Reflection's SetString (#6477)
378
379  Java
380  * Call loadDescriptor outside of synchronized block to remove one possible source of deadlock.
381  * Have oneof enums implement a separate interface (other than EnumLite) for clarity.
382  * Opensource Android Memory Accessors
383  * Update TextFormat to make use of the new TypeRegistry.
384  * Support getFieldBuilder and getRepeatedFieldBuilder in ExtendableBuilder
385  * Update JsonFormat to make use of the new TypeRegistry.
386  * Add proguard config generator for GmmBenchmarkSuiteLite.
387  * Change ProtobufArrayList to use Object[] instead of ArrayList for 5-10% faster parsing
388  * Implement ProtobufArrayList.add(E) for 20% (5%-40%) faster overall protolite2 parsing
389  * Make a copy of JsonFormat.TypeRegistry at the protobuf top level package. This will eventually replace JsonFormat.TypeRegistry.
390  * Fix javadoc warnings in generated files (#6231)
391  * Java: Add Automatic-Module-Name entries to the Manifest (#6568)
392
393  Python
394  * Add descriptor methods in descriptor_pool are deprecated.
395  * Uses explicit imports to prevent multithread test failures in py3.
396  * Added __delitem__ for Python extension dict
397  * Update six version to 1.12.0 and fix legacy_create_init issue (#6391)
398
399  JavaScript
400  * Remove deprecated boolean option to getResultBase64String().
401  * Fix sint64 zig-zag encoding.
402  * Simplify hash64 string conversion to avoid DIGIT array. Should reduce overhead if these functions aren't used, and be more efficient by avoiding linear array searches.
403  * Change the parameter types of binaryReaderFn in ExtensionFieldBinaryInfo to (number, ?, ?).
404  * Create dates.ts and time_of_days.ts to mirror Java versions. This is a near-identical conversion of c.g.type.util.{Dates,TimeOfDays} respectively.
405  * Migrate moneys to TypeScript.
406
407  PHP
408  * Fix incorrect leap day for Timestamp (#6696)
409  * Initialize well known type values (#6713)
410
411  Ruby
412  * Fix scope resolution for Google namespace (#5878)
413  * Support hashes for struct initializers (#5716)
414  * Optimized away the creation of empty string objects. (#6502)
415  * Roll forward Ruby upb changes now that protobuf Ruby build is fixed (#5866)
416  * Optimized layout_mark() for Ruby (#6521)
417  * Optimization for layout_init() (#6547)
418  * Fix for GC of Ruby map frames. (#6533)
419  * Fixed leap year handling by reworking upb_mktime() -> upb_timegm(). (#6695)
420
421  Objective C
422  * Remove OSReadLittle* due to alignment requirements (#6678)
423  * Don't use unions and instead use memcpy for the type swaps. (#6672)
424
425  Other
426  * Override CocoaPods module to lowercase (#6464)
427
428
4292019-06-28 version 3.9.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
430
431  C++
432  * Optimize and simplify implementation of RepeatedPtrFieldBase
433  * Don't create unnecessary unknown field sets.
434  * Remove branch from accessors to repeated field element array.
435  * Added delimited parse and serialize util.
436  * Reduce size by not emitting constants for fieldnumbers
437  * Fix a bug when comparing finite and infinite field values with explicit tolerances.
438  * TextFormat::Parser should use a custom Finder to look up extensions by number if one is provided.
439  * Add MessageLite::Utf8DebugString() to make MessageLite more compatible with Message.
440  * Fail fast for better performance in DescriptorPool::FindExtensionByNumber() if descriptor has no defined extensions.
441  * Adding the file name to help debug colliding extensions
442  * Added FieldDescriptor::PrintableNameForExtension() and DescriptorPool::FindExtensionByPrintableName().
443    The latter will replace Reflection::FindKnownExtensionByName().
444  * Replace NULL with nullptr
445  * Created a new Add method in repeated field that allows adding a range of elements all at once.
446  * Enabled enum name-to-value mapping functions for C++ lite
447  * Avoid dynamic initialization in descriptor.proto generated code
448  * Move stream functions to MessageLite from Message.
449  * Move all zero_copy_stream functionality to io_lite.
450  * Do not create array of matched fields for simple repeated fields
451  * Enabling silent mode by default to reduce make compilation noise. (#6237)
452
453  Java
454  * Expose TextFormat.Printer and make it configurable. Deprecate the static methods.
455  * Library for constructing google.protobuf.Struct and google.protobuf.Value
456  * Make OneofDescriptor extend GenericDescriptor.
457  * Expose streamingness of service methods from MethodDescriptor.
458  * Fix a bug where TextFormat fails to parse Any filed with > 1 embedded message sub-fields.
459  * Establish consistent JsonFormat behavior for nulls in oneofs, regardless of order.
460  * Update GSON version to 3.8.5. (#6268)
461  * Add `protobuf_java_lite` Bazel target. (#6177)
462
463  Python
464  * Change implementation of Name() for enums that allow aliases in proto2 in Python
465    to be in line with claims in C++ implementation (to return first value).
466  * Explicitly say what field cannot be set when the new value fails a type check.
467  * Duplicate register in descriptor pool will raise errors
468  * Add __slots__ to all well_known_types classes, custom attributes are not allowed anymore.
469  * text_format only present 8 valid digits for float fields by default
470
471  JavaScript
472  * Add Oneof enum to the list of goog.provide
473
474  PHP
475  * Make php message class final to avoid mocking. (#6277)
476  * Rename get/setXXXValue to get/setXXXWrapper. (#6295)
477
478  Ruby
479  * Remove to_hash methods. (#6166)
480
481
4822019-04-29 version 3.8.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
483
484  C++
485  * Use std::atomic<int32> in case of myriad2 platform
486  * Always declare enums to be int-sized
487  * Added DebugString() and ShortDebugString() methods on MessageLite
488  * Specialized different parse loop control flows
489  * Make hasbits potentially in register. The or's start forming an obstacle because it's a read modify store on the same mem address on each iteration.
490  * Move to an internal MACRO for parser validity checks.
491  * Improve map parsing performance.
492  * Make MergePartialFromCodedStream non virtual. This allows direct calls, potential inlining and is also a code health improvement
493  * Add an overall limit to parse_context to prevent reading past it. This allows to remove a annoying level of indirection.
494  * Fix a mistake, we shouldn't verify map key/value strings for utf8 in opt mode for proto2.
495  * Further improvements to cut binary size.
496  * Prepare to make MergePartialFromCodedStream non-virtual.
497  * A report on some interesting behavior change in python (caused by b/27494216) made me realize there is a check that needs to be done in case the parse ended on a end group tag.
498  * Add a note of caution to the comments around skip in CodedOutputStream.
499  * Simplify end check.
500  * Add overload for ParseMessage for MessageLite/Message types. If the explicit type is not known inlining won't help de-virtualizing the virtual call.
501  * Reduce linker input. It turns out that ParseMessage is not inlined, producing  template instantiations that are used only once and save nothing but cost more.
502  * Improve the parser.
503  * [c++17] Changed proto2::RepeatedPtrField iterators to no longer derive from the deprecated std::iterator class.
504  * Change the default value of case_insensitive_enum_parsing to false for JsonStringToMessage.
505  * Add a warning if a field name doesn't match the style guide.
506  * Fix TextFormat not round-trip correctly when float value is max float.
507  * Added locationed info for some errors at compiler
508  * Python reserved keywords are now working with getattr()/setattr() for most descriptors.
509  * Added AllowUnknownField() in text_format
510  * Append '_' to C++ reserved keywords for message, enum, extension
511  * Fix MSVC warning C4244 in protobuf's parse_context.h.
512  * Updating Iterators to be compatible with C++17 in MSVC.
513  * Use capability annotation in mutex.h
514  * Fix "UndefinedBehaviorSanitizer: cfi-bad-type"
515  * CriticalSectionLock class as a lightweight replacement for std::mutex on Windows platforms.
516  * Removed vestigial wire_format_lite_inl.h
517
518  C#
519  * Added System.Memory dependency.
520
521  Java
522  * Make Java protoc code generator ignore optimize_for LITE_RUNTIME. Users should instead use the Java lite protoc plugin.
523  * Change Extension getMessageDefaultInstance() to return Message instead of MessageLite.
524  * Prevent malicious input streams from leaking buffers for ByteString or ByteBuffer parsing.
525  * Release new Javalite runtime.
526  * Show warning in case potential file name conflict.
527  * Allow Java reserved keywords to be used in extensions.
528  * Added setAllowUnknownFields() in text format
529  * Add memoization to ExtensionRegistryLite.getEmptyRegistry()
530  * Improve performance of CodedOutputStream.writeUInt32NoTag
531  * Add an optimized mismatch-finding algorithm to UnsafeUtil.
532  * When serializing uint32 varints, check that we have MAX_VARINT32_SIZE bytes left, not just MAX_VARINT_SIZE.
533  * Minor optimization to RopeByteString.PieceIterator
534
535  JavaScript
536  * Simplify generated toObject code when the default value is used.
537
538  Python
539  * Changes implementation of Name() for enums that allow aliases in proto2 in Python to be in line with claims in C++ implementation (to return first value).
540  * Added double_format option in text format printer.
541  * Added iter and __contains__ to extension dict
542  * Added allow_unknown_field option in python text format parser
543  * Fixed Timestamp.ToDatetime() loses precision issue
544  * Support unknown field in text format printer.
545  * Float field will be convert to inf if bigger than struct.unpack('f', b'\xff\xff\x7f\x7f')[0] which is about 3.4028234664e+38,
546  convert to -inf if smaller than -3.4028234664e+38
547  * Allowed casting str->bytes in Message.__setstate__
548
549  Ruby
550  * Helper methods to get enum name for Ruby.
551
552
5532019-01-24 version 3.7.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
554
555  C++
556  * Introduced new MOMI (maybe-outside-memory-interval) parser.
557  * Add an option to json_util to parse enum as case-insensitive. In the future, enum parsing in json_util will become case-sensitive.
558  * Added conformance test for enum aliases
559  * Added support for --cpp_out=speed:...
560  * Added use of C++ override keyword where appropriate
561  * Many other cleanups and fixes.
562
563  Java
564  * Fix illegal reflective access warning in JDK 9+
565  * Add BOM
566
567  Python
568  * Added Python 3.7 compatibility.
569  * Modified ParseFromString to return bytes parsed .
570  * Introduce Proto C API.
571  * FindFileContainingSymbol in descriptor pool is now able to find field and enum values.
572  * reflection.MakeClass()  and  reflection.ParseMessage() are deprecated.
573  * Added DescriptorPool.FindMethodByName() method in pure python (c extension already has it)
574  * Flipped proto3 to preserve unknown fields by default.
575  * Added support for memoryview in python3 proto message parsing.
576  * Added MergeFrom for repeated scalar fields in c extension (pure python already has it)
577  * Surrogates are now rejected at setters in python3.
578  * Added public unknown field API.
579  * RecursionLimit is also set to max if allow_oversize_protos is enabled.
580  * Disallow duplicate scalars in proto3 text_format parse.
581  * Fix some segment faults for c extension map field.
582
583  PHP
584  * Most issues for json encoding/decoding in the c extension have been fixed. There are still some edge cases not fixed. For more details, check conformance/failure_list_php_c.txt.
585  * Supports php 7.3
586  * Added helper methods to convert between enum values and names.
587  * Allow setting/getting wrapper message fields using primitive values.
588  * Various bug fixes.
589
590  Ruby
591  * Ruby 2.6 support.
592  * Drops support for ruby < 2.3.
593  * Most issues for json encoding/decoding in the c extension have been fixed. There are still some edge cases not fixed. For more details, check conformance/failure_list_ruby.txt.
594  * Json parsing can specify an option to ignore unknown fields: msg.decode_json(data, {ignore_unknown_fields: true}).
595  * Added support for proto2 syntax (partially).
596  * Various bug fixes.
597
598  Csharp
599  * More support for FieldMask include merge, intersect and more.
600  * Increasing the default recursion limit to 100.
601  * Support loading FileDescriptors dynamically.
602  * Provide access to comments from descriptors.
603  * Added Any.Is method.
604  * Compatible with C# 6
605  * Added IComparable and comparison operators on Timestamp.
606
607  Objective C
608  * Add ability to introspect list of enum values (#4678)
609  * Copy the value when setting message/data fields (#5215)
610  * Support suppressing the objc package prefix checks on a list of files (#5309)
611  * More complete keyword and NSObject method (via categories) checks for field names, can result in more fields being rename, but avoids the collisions at runtime (#5289)
612  * Small fixes to TextFormat generation for extensions (#5362)
613  * Provide more details/context in deprecation messages (#5412)
614  * Array/Dictionary enumeration blocks NS_NOESCAPE annotation for Swift (#5421)
615  * Properly annotate extensions for ARC when their names imply behaviors (#5427)
616  * Enum alias name collision improvements (#5480)
617
618
6192018-07-27 version 3.6.1 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
620
621  C++
622  * Introduced workaround for Windows issue with std::atomic and std::once_flag
623    initialization (#4777, #4773).
624
625  PHP
626  * Added compatibility with PHP 7.3 (#4898).
627
628  Ruby
629  * Fixed Ruby crash involving Any encoding (#4718).
630
6312018-06-01 version 3.6.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
632
633  C++
634  * Starting from this release, we now require C++11. For those we cannot yet
635    upgrade to C++11, we will try to keep the 3.5.x branch updated with
636    critical bug fixes only. If you have any concerns about this, please
637    comment on issue #2780.
638  * Moved to C++11 types like std::atomic and std::unique_ptr and away from our
639    old custom-built equivalents.
640  * Added support for repeated message fields in lite protos using implicit
641    weak fields. This is an experimental feature that allows the linker to
642    strip out more unused messages than previously was possible.
643  * Fixed SourceCodeInfo for interpreted options and extension range options.
644  * Fixed always_print_enums_as_ints option for JSON serialization.
645  * Added support for ignoring unknown enum values when parsing JSON.
646  * Create std::string in Arena memory.
647  * Fixed ValidateDateTime to correctly check the day.
648  * Fixed bug in ZeroCopyStreamByteSink.
649  * Various other cleanups and fixes.
650
651  Java
652  * Dropped support for Java 6.
653  * Added a UTF-8 decoder that uses Unsafe to directly decode a byte buffer.
654  * Added deprecation annotations to generated code for deprecated oneof
655    fields.
656  * Fixed map field serialization in DynamicMessage.
657  * Cleanup and documentation for Java Lite runtime.
658  * Various other fixes and cleanups
659  * Fixed unboxed arraylists to handle an edge case
660  * Improved performance for copying between unboxed arraylists
661  * Fixed lite protobuf to avoid Java compiler warnings
662  * Improved test coverage for lite runtime
663  * Performance improvements for lite runtime
664
665  Python
666  * Fixed bytes/string map key incompatibility between C++ and pure-Python
667    implementations (issue #4029)
668  * Added __init__.py files to compiler and util subpackages
669  * Use /MT for all Windows versions
670  * Fixed an issue affecting the Python-C++ implementation when used with
671    Cython (issue #2896)
672  * Various text format fixes
673  * Various fixes to resolve behavior differences between the pure-Python and
674    Python-C++ implementations
675
676  PHP
677  * Added php_metadata_namespace to control the file path of generated metadata
678    file.
679  * Changed generated classes of nested message/enum. E.g., Foo.Bar, which
680    previously generates Foo_Bar, now generates Foo/Bar
681  * Added array constructor. When creating a message, users can pass a php
682    array whose content is field name to value pairs into constructor. The
683    created message will be initialized according to the array. Note that
684    message field should use a message value instead of a sub-array.
685  * Various bug fixes.
686
687  Objective-C
688  * We removed some helper class methods from GPBDictionary to shrink the size
689    of the library, the functionary is still there, but you may need to do some
690    specific +alloc / -init… methods instead.
691  * Minor improvements in the performance of object field getters/setters by
692    avoiding some memory management overhead.
693  * Fix a memory leak during the raising of some errors.
694  * Make header importing completely order independent.
695  * Small code improvements for things the undefined behaviors compiler option
696    was flagging.
697
698  Ruby
699  * Added ruby_package file option to control the module of generated class.
700  * Various bug fixes.
701
702  Javascript
703  * Allow setting string to int64 field.
704
705  Csharp
706  * Unknown fields are now parsed and then sent back on the wire. They can be
707    discarded at parse time via a CodedInputStream option.
708  * Movement towards working with .NET 3.5 and Unity
709  * Expression trees are no longer used
710  * AOT generics issues in Unity/il2cpp have a workaround (see this commit for
711    details)
712  * Floating point values are now compared bitwise (affects NaN value
713    comparisons)
714  * The default size limit when parsing is now 2GB rather than 64MB
715  * MessageParser now supports parsing from a slice of a byte array
716  * JSON list parsing now accepts null values where the underlying proto
717    representation does
718
7192017-12-20 version 3.5.1 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
720  Planned Future Changes
721  * Make C++ implementation C++11 only: we plan to require C++11 to build
722    protobuf code starting from 3.6.0 release. Please join this github issue:
723    https://github.com/protocolbuffers/protobuf/issues/2780 to provide your feedback.
724
725  protoc
726  * Fixed a bug introduced in 3.5.0 and protoc in Windows now accepts non-ascii
727    characters in paths again.
728
729  C++
730  * Removed several usages of C++11 features in the code base.
731  * Fixed some compiler warnings.
732
733  PHP
734  * Fixed memory leak in C-extension implementation.
735  * Added discardUnknokwnFields API.
736  * Removed duplicated typedef in C-extension headers.
737  * Avoided calling private php methods (timelib_update_ts).
738  * Fixed Any.php to use fully-qualified name for DescriptorPool.
739
740  Ruby
741  * Added Google_Protobuf_discard_unknown for discarding unknown fields in
742    messages.
743
744  C#
745  * Unknown fields are now preserved by default.
746  * Floating point values are now bitwise compared, affecting message equality
747    check and Contains() API in map and repeated fields.
748
749
7502017-11-13 version 3.5.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
751  Planned Future Changes
752  * Make C++ implementation C++11 only: we plan to require C++11 to build
753    protobuf code starting from 3.6.0 release. Please join this github issue:
754    https://github.com/protocolbuffers/protobuf/issues/2780 to provide your feedback.
755
756  General
757  * Unknown fields are now preserved in proto3 for most of the language
758    implementations for proto3 by default. See the per-language section for
759    details.
760  * reserve keyword are now supported in enums
761
762  C++
763  * Proto3 messages are now preserving unknown fields by default. If you rely on
764    unknowns fields being dropped. Please use DiscardUnknownFields() explicitly.
765  * Deprecated the unsafe_arena_release_* and unsafe_arena_add_allocated_*
766    methods for string fields.
767  * Added move constructor and move assignment to RepeatedField,
768    RepeatedPtrField and google::protobuf::Any.
769  * Added perfect forwarding in Arena::CreateMessage
770  * In-progress experimental support for implicit weak fields with lite protos.
771    This feature allows the linker to strip out more unused messages and reduce
772    binary size.
773  * Various performance optimizations.
774
775  Java
776  * Proto3 messages are now preserving unknown fields by default. If you’d like
777    to drop unknown fields, please use the DiscardUnknownFieldsParser API. For
778    example:
779      Parser<Foo> parser = DiscardUnknownFieldsParser.wrap(Foo.parser());
780      Foo foo = parser.parseFrom(input);
781  * Added a new CodedInputStream decoder for Iterable<ByteBuffer> with direct
782    ByteBuffers.
783  * TextFormat now prints unknown length-delimited fields as messages if
784    possible.
785  * FieldMaskUtil.merge() no longer creates unnecessary empty messages when a
786    message field is unset in both source message and destination message.
787  * Various performance optimizations.
788
789  Python
790  * Proto3 messages are now preserving unknown fields by default. Use
791    message.DiscardUnknownFields() to drop unknown fields.
792  * Add FieldDescriptor.file in generated code.
793  * Add descriptor pool FindOneofByName in pure python.
794  * Change unknown enum values into unknown field set .
795  * Add more Python dict/list compatibility for Struct/ListValue.
796  * Add utf-8 support for text_format.Merge()/Parse().
797  * Support numeric unknown enum values for proto3 JSON format.
798  * Add warning for Unexpected end-group tag in cpp extension.
799
800  PHP
801  * Proto3 messages are now preserving unknown fields.
802  * Provide well known type messages in runtime.
803  * Add prefix ‘PB’ to generated class of reserved names.
804  * Fixed all conformance tests for encode/decode json in php runtime. C
805    extension needs more work.
806
807  Objective-C
808  * Fixed some issues around copying of messages with unknown fields and then
809    mutating the unknown fields in the copy.
810
811  C#
812  * Added unknown field support in JsonParser.
813  * Fixed oneof message field merge.
814  * Simplify parsing messages from array slices.
815
816  Ruby
817  * Unknown fields are now preserved by default.
818  * Fixed several bugs for segment fault.
819
820  Javascript
821  * Decoder can handle both paced and unpacked data no matter how the proto is
822    defined.
823  * Decoder now accept long varint for 32 bit integers.
824
825
8262017-08-14 version 3.4.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
827  Planned Future Changes
828  * There are some changes that are not included in this release but are planned
829    for the near future
830      - Preserve unknown fields in proto3: We are going to bring unknown fields
831        back into proto3. In this release, some languages start to support
832        preserving unknown fields in proto3, controlled by flags/options. Some
833        languages also introduce explicit APIs to drop unknown fields for
834        migration. Please read the change log sections by languages for details.
835        For general timeline and plan:
836
837          https://docs.google.com/document/d/1KMRX-G91Aa-Y2FkEaHeeviLRRNblgIahbsk4wA14gRk/view
838
839        For issues and discussions:
840
841          https://github.com/protocolbuffers/protobuf/issues/272
842
843      - Make C++ implementation C++11 only: we plan to require C++11 to build
844        protobuf code starting from 3.5.0 or 3.6.0 release, after unknown fields
845        semantic changes are finished. Please join this
846        github issue:
847
848          https://github.com/protocolbuffers/protobuf/issues/2780
849
850        to provide your feedback.
851
852  General
853  * Extension ranges now accept options and are customizable.
854  * "reserve" keyword now supports “max” in field number ranges,
855    e.g.  reserve 1000 to max;
856
857  C++
858  * Proto3 messages are now able to preserve unknown fields. The default
859    behavior is still to drop unknowns, which will be flipped in a future
860    release. If you rely on unknowns fields being dropped. Please use
861    Message::DiscardUnknownFields() explicitly.
862  * Packable proto3 fields are now packed by default in serialization.
863  * Following C++11 features are introduced when C++11 is available:
864      - move-constructor and move-assignment are introduced to messages
865      - Repeated fields constructor now takes std::initializer_list
866      - rvalue setters are introduced for string fields
867  * Experimental Table-Driven parsing and serialization available to test. To
868    enable it, pass in table_driven_parsing table_driven_serialization protoc
869    generator flags for C++
870
871      $ protoc --cpp_out=table_driven_parsing,table_driven_serialization:./ \
872        test.proto
873
874  * lite generator parameter supported by the generator. Once set, all generated
875    files, use lite runtime regardless of the optimizer_for setting in the
876    .proto file.
877  * Various optimizations to make C++ code more performant on PowerPC platform
878  * Fixed maps data corruption when the maps are modified by both reflection API
879    and generated API.
880  * Deterministic serialization on maps reflection now uses stable sort.
881  * file() accessors are introduced to various *Descriptor classes to make
882    writing template function easier.
883  * ByteSize() and SpaceUsed() are deprecated.Use ByteSizeLong() and
884    SpaceUsedLong() instead
885  * Consistent hash function is used for maps in DEBUG and NDEBUG build.
886  * "using namespace std" is removed from stubs/common.h
887  * Various performance optimizations and bug fixes
888
889  Java
890  * Introduced new parser API DiscardUnknownFieldsParser in preparation of
891    proto3 unknown fields preservation change. Users who want to drop unknown
892    fields should migrate to use this new parser API. For example:
893
894      Parser<Foo> parser = DiscardUnknownFieldsParser.wrap(Foo.parser());
895      Foo foo = parser.parseFrom(input);
896
897  * Introduced new TextFormat API printUnicodeFieldValue() that prints field
898    value without escaping unicode characters.
899  * Added Durations.compare(Duration, Duration) and
900    Timestamps.compare(Timestamp, Timestamp).
901  * JsonFormat now accepts base64url encoded bytes fields.
902  * Optimized CodedInputStream to do less copies when parsing large bytes
903    fields.
904  * Optimized TextFormat to allocate less memory when printing.
905
906  Python
907  * SerializeToString API is changed to SerializeToString(self, **kwargs),
908    deterministic parameter is accepted for deterministic serialization.
909  * Added sort_keys parameter in json format to make the output deterministic.
910  * Added indent parameter in json format.
911  * Added extension support in json format.
912  * Added __repr__ support for repeated field in cpp implementation.
913  * Added file in FieldDescriptor.
914  * Added pretty-print filter to text format.
915  * Services and method descriptors are always printed even if generic_service
916    option is turned off.
917  * Note: AppEngine 2.5 is deprecated on June 2017 that AppEngine 2.5 will
918    never update protobuf runtime. Users who depend on AppEngine 2.5 should use
919    old protoc.
920
921  PHP
922  * Support PHP generic services. Specify file option php_generic_service=true
923    to enable generating service interface.
924  * Message, repeated and map fields setters take value instead of reference.
925  * Added map iterator in c extension.
926  * Support json  encode/decode.
927  * Added more type info in getter/setter phpdoc
928  * Fixed the problem that c extension and php implementation cannot be used
929    together.
930  * Added file option php_namespace to use custom php namespace instead of
931    package.
932  * Added fluent setter.
933  * Added descriptor API in runtime for custom encode/decode.
934  * Various bug fixes.
935
936  Objective-C
937  * Fix for GPBExtensionRegistry copying and add tests.
938  * Optimize GPBDictionary.m codegen to reduce size of overall library by 46K
939    per architecture.
940  * Fix some cases of reading of 64bit map values.
941  * Properly error on a tag with field number zero.
942  * Preserve unknown fields in proto3 syntax files.
943  * Document the exceptions on some of the writing apis.
944
945  C#
946  * Implemented IReadOnlyDictionary<K,V> in MapField<K,V>
947  * Added TryUnpack method for Any message in addition to Unpack.
948  * Converted C# projects to MSBuild (csproj) format.
949
950  Ruby
951  * Several bug fixes.
952
953  Javascript
954  * Added support of field option js_type. Now one can specify the JS type of a
955    64-bit integer field to be string in the generated code by adding option
956    [jstype = JS_STRING] on the field.
957
9582017-04-05 version 3.3.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
959  Planned Future Changes
960  * There are some changes that are not included in this release but are
961    planned for the near future:
962      - Preserve unknown fields in proto3: please read this doc:
963
964          https://docs.google.com/document/d/1KMRX-G91Aa-Y2FkEaHeeviLRRNblgIahbsk4wA14gRk/view
965
966        for the timeline and follow up this github issue:
967
968          https://github.com/protocolbuffers/protobuf/issues/272
969
970        for discussion.
971      - Make C++ implementation C++11 only: we plan to require C++11 to build
972        protobuf code starting from 3.4.0 or 3.5.0 release. Please join this
973        github issue:
974
975          https://github.com/protocolbuffers/protobuf/issues/2780
976
977        to provide your feedback.
978
979  C++
980  * Fixed map fields serialization of DynamicMessage to correctly serialize
981    both key and value regardless of their presence.
982  * Parser now rejects field number 0 correctly.
983  * New API Message::SpaceUsedLong() that’s equivalent to
984    Message::SpaceUsed() but returns the value in size_t.
985  * JSON support
986    - New flag always_print_enums_as_ints in JsonPrintOptions.
987    - New flag preserve_proto_field_names in JsonPrintOptions. It will instruct
988      the JSON printer to use the original field name declared in the .proto
989      file instead of converting them to lowerCamelCase when printing JSON.
990    - JsonPrintOptions.always_print_primtive_fields now works for oneof message
991      fields.
992    - Fixed a bug that doesn’t allow different fields to set the same json_name
993      value.
994    - Fixed a performance bug that causes excessive memory copy when printing
995      large messages.
996  * Various performance optimizations.
997
998  Java
999  * Map field setters eagerly validate inputs and throw NullPointerExceptions
1000    as appropriate.
1001  * Added ByteBuffer overloads to the generated parsing methods and the Parser
1002    interface.
1003  * proto3 enum's getNumber() method now throws on UNRECOGNIZED values.
1004  * Output of JsonFormat is now locale independent.
1005
1006  Python
1007  * Added FindServiceByName() in the pure-Python DescriptorPool. This works only
1008    for descriptors added with DescriptorPool.Add(). Generated descriptor_pool
1009    does not support this yet.
1010  * Added a descriptor_pool parameter for parsing Any in text_format.Parse().
1011  * descriptor_pool.FindFileContainingSymbol() now is able to find nested
1012    extensions.
1013  * Extending empty [] to repeated field now sets parent message presence.
1014
1015  PHP
1016  * Added file option php_class_prefix. The prefix will be prepended to all
1017    generated classes defined in the file.
1018  * When encoding, negative int32 values are sign-extended to int64.
1019  * Repeated/Map field setter accepts a regular PHP array. Type checking is
1020    done on the array elements.
1021  * encode/decode are renamed to serializeToString/mergeFromString.
1022  * Added mergeFrom, clear method on Message.
1023  * Fixed a bug that oneof accessor didn’t return the field name that is
1024    actually set.
1025  * C extension now works with php7.
1026  * This is the first GA release of PHP. We guarantee that old generated code
1027    can always work with new runtime and new generated code.
1028
1029  Objective-C
1030  * Fixed help for GPBTimestamp for dates before the epoch that contain
1031    fractional seconds.
1032  * Added GPBMessageDropUnknownFieldsRecursively() to remove unknowns from a
1033    message and any sub messages.
1034  * Addressed a threading race in extension registration/lookup.
1035  * Increased the max message parsing depth to 100 to match the other languages.
1036  * Removed some use of dispatch_once in favor of atomic compare/set since it
1037    needs to be heap based.
1038  * Fixes for new Xcode 8.3 warnings.
1039
1040  C#
1041  * Fixed MapField.Values.CopyTo, which would throw an exception unnecessarily
1042    if provided exactly the right size of array to copy to.
1043  * Fixed enum JSON formatting when multiple names mapped to the same numeric
1044    value.
1045  * Added JSON formatting option to format enums as integers.
1046  * Modified RepeatedField<T> to implement IReadOnlyList<T>.
1047  * Introduced the start of custom option handling; it's not as pleasant as it
1048    might be, but the information is at least present. We expect to extend code
1049    generation to improve this in the future.
1050  * Introduced ByteString.FromStream and ByteString.FromStreamAsync to
1051    efficiently create a ByteString from a stream.
1052  * Added whole-message deprecation, which decorates the class with [Obsolete].
1053
1054  Ruby
1055  * Fixed Message#to_h for messages with map fields.
1056  * Fixed memcpy() in binary gems to work for old glibc, without breaking the
1057    build for non-glibc libc’s like musl.
1058
1059  Javascript
1060  * Added compatibility tests for version 3.0.0.
1061  * Added conformance tests.
1062  * Fixed serialization of extensions: we need to emit a value even if it is
1063    falsy (like the number 0).
1064  * Use closurebuilder.py in favor of calcdeps.py for compiling JavaScript.
1065
10662017-01-23 version 3.2.0 (C++/Java/Python/PHP/Ruby/Objective-C/C#/JavaScript/Lite)
1067  General
1068  * Added protoc version number to protoc plugin protocol. It can be used by
1069    protoc plugin to detect which version of protoc is used with the plugin and
1070    mitigate known problems in certain version of protoc.
1071
1072  C++
1073  * The default parsing byte size limit has been raised from 64MB to 2GB.
1074  * Added rvalue setters for non-arena string fields.
1075  * Enabled debug logging for Android.
1076  * Fixed a double-free problem when using Reflection::SetAllocatedMessage()
1077    with extension fields.
1078  * Fixed several deterministic serialization bugs:
1079    * MessageLite::SerializeAsString() now respects the global deterministic
1080      serialization flag.
1081    * Extension fields are serialized deterministically as well.  Fixed protocol
1082      compiler to correctly report importing-self as an error.
1083  * Fixed FileDescriptor::DebugString() to print custom options correctly.
1084  * Various performance/codesize optimizations and cleanups.
1085
1086  Java
1087  * The default parsing byte size limit has been raised from 64MB to 2GB.
1088  * Added recursion limit when parsing JSON.
1089  * Fixed a bug that enumType.getDescriptor().getOptions() doesn't have custom
1090    options.
1091  * Fixed generated code to support field numbers up to 2^29-1.
1092
1093  Python
1094  * You can now assign NumPy scalars/arrays (np.int32, np.int64) to protobuf
1095    fields, and assigning other numeric types has been optimized for
1096    performance.
1097  * Pure-Python: message types are now garbage-collectable.
1098  * Python/C++: a lot of internal cleanup/refactoring.
1099
1100  PHP (Alpha)
1101  * For 64-bit integers type (int64/uint64/sfixed64/fixed64/sint64), use PHP
1102    integer on 64-bit environment and PHP string on 32-bit environment.
1103  * PHP generated code also conforms to PSR-4 now.
1104  * Fixed ZTS build for c extension.
1105  * Fixed c extension build on Mac.
1106  * Fixed c extension build on 32-bit linux.
1107  * Fixed the bug that message without namespace is not found in the descriptor
1108    pool. (#2240)
1109  * Fixed the bug that repeated field is not iterable in c extension.
1110  * Message names Empty will be converted to GPBEmpty in generated code.
1111  * Added phpdoc in generated files.
1112  * The released API is almost stable. Unless there is large problem, we won't
1113    change it. See
1114    https://developers.google.com/protocol-buffers/docs/reference/php-generated
1115    for more details.
1116
1117  Objective-C
1118  * Added support for push/pop of the stream limit on CodedInputStream for
1119    anyone doing manual parsing.
1120
1121  C#
1122  * No changes.
1123
1124  Ruby
1125  * Message objects now support #respond_to? for field getters/setters.
1126  * You can now compare “message == non_message_object” and it will return false
1127    instead of throwing an exception.
1128  * JRuby: fixed #hashCode to properly reflect the values in the message.
1129
1130  Javascript
1131  * Deserialization of repeated fields no longer has quadratic performance
1132    behavior.
1133  * UTF-8 encoding/decoding now properly supports high codepoints.
1134  * Added convenience methods for some well-known types: Any, Struct, and
1135    Timestamp. These make it easier to convert data between native JavaScript
1136    types and the well-known protobuf types.
1137
11382016-09-23 version 3.1.0 (C++/Java/Python/PHP/Ruby/Objective-C/C#/JavaScript/Lite)
1139  General
1140  * Proto3 support in PHP (alpha).
1141  * Various bug fixes.
1142
1143  C++
1144  * Added MessageLite::ByteSizeLong() that’s equivalent to
1145    MessageLite::ByteSize() but returns the value in size_t. Useful to check
1146    whether a message is over the 2G size limit that protobuf can support.
1147  * Moved default_instances to global variables. This allows default_instance
1148    addresses to be known at compile time.
1149  * Adding missing generic gcc 64-bit atomicops.
1150  * Restore New*Callback into google::protobuf namespace since these are used
1151    by the service stubs code
1152  * JSON support.
1153    * Fixed some conformance issues.
1154  * Fixed a JSON serialization bug for bytes fields.
1155
1156  Java
1157  * Fixed a bug in TextFormat that doesn’t accept empty repeated fields (i.e.,
1158    “field: [ ]”).
1159  * JSON support
1160    * Fixed JsonFormat to do correct snake_case-to-camelCase conversion for
1161      non-style-conforming field names.
1162    * Fixed JsonFormat to parse empty Any message correctly.
1163    * Added an option to JsonFormat.Parser to ignore unknown fields.
1164  * Experimental API
1165    * Added UnsafeByteOperations.unsafeWrap(byte[]) to wrap a byte array into
1166      ByteString without copy.
1167
1168  Python
1169  * JSON support
1170    * Fixed some conformance issues.
1171
1172  PHP (Alpha)
1173  * We have added the proto3 support for PHP via both a pure PHP package and a
1174    native c extension. The pure PHP package is intended to provide usability
1175    to wider range of PHP platforms, while the c extension is intended to
1176    provide higher performance. Both implementations provide the same runtime
1177    APIs and share the same generated code. Users don’t need to re-generate
1178    code for the same proto definition when they want to switch the
1179    implementation later. The pure PHP package is included in the php/src
1180    directory, and the c extension is included in the php/ext directory.
1181
1182    Both implementations provide idiomatic PHP APIs:
1183    * All messages and enums are defined as PHP classes.
1184    * All message fields can only be accessed via getter/setter.
1185    * Both repeated field elements and map elements are stored in containers
1186      that act like a normal PHP array.
1187
1188    Unlike several existing third-party PHP implementations for protobuf, our
1189    implementations are built on a "strongly-typed" philosophy: message fields
1190    and array/map containers will throw exceptions eagerly when values of the
1191    incorrect type (not including those that can be type converted, e.g.,
1192    double <-> integer <-> numeric string) are inserted.
1193
1194    Currently, pure PHP runtime supports php5.5, 5.6 and 7 on linux. C
1195    extension runtime supports php5.5 and 5.6 on linux.
1196
1197    See php/README.md for more details about installment. See
1198    https://developers.google.com/protocol-buffers/docs/phptutorial for more
1199    details about APIs.
1200
1201  Objective-C
1202  * Helpers are now provided for working the Any well known type (see
1203    GPBWellKnownTypes.h for the api additions).
1204  * Some improvements in startup code (especially when extensions aren’t used).
1205
1206  Javascript
1207  * Fixed missing import of jspb.Map
1208  * Fixed valueWriterFn variable name
1209
1210  Ruby
1211  * Fixed hash computation for JRuby's RubyMessage
1212  * Make sure map parsing frames are GC-rooted.
1213  * Added API support for well-known types.
1214
1215  C#
1216  * Removed check on dependency in the C# reflection API.
1217
12182016-09-06 version 3.0.2 (C++/Java/Python/Ruby/Objective-C/C#/JavaScript/Lite)
1219  General
1220  * Various bug fixes.
1221
1222  Objective C
1223  * Fix for oneofs in proto3 syntax files where fields were set to the zero
1224    value.
1225  * Fix for embedded null character in strings.
1226  * CocoaDocs support
1227
1228  Ruby
1229  * Fixed memory corruption bug in parsing that could occur under GC pressure.
1230
1231  Javascript
1232  * jspb.Map is now properly exported to CommonJS modules.
1233
1234  C#
1235  * Removed legacy_enum_values flag.
1236
1237
12382016-07-27 version 3.0.0 (C++/Java/Python/Ruby/Objective-C/C#/JavaScript/Lite)
1239  General
1240  * This log only contains changes since the beta-4 release. Summarized change
1241    log since the last stable release (v2.6.1) can be found in the github
1242    release page.
1243
1244  Compatibility Notice
1245  * v3.0.0 is the first API stable release of the v3.x series. We do not expect
1246    any future API breaking changes.
1247  * For C++, Java Lite and Objective-C, source level compatibility is
1248    guaranteed.  Upgrading from v3.0.0 to newer minor version releases will be
1249    source compatible. For example, if your code compiles against protobuf
1250    v3.0.0, it will continue to compile after you upgrade protobuf library to
1251    v3.1.0.
1252  * For other languages, both source level compatibility and binary level
1253    compatibility are guaranteed. For example, if you have a Java binary built
1254    against protobuf v3.0.0. After switching the protobuf runtime binary to
1255    v3.1.0, your built binary should continue to work.
1256  * Compatibility is only guaranteed for documented API and documented
1257    behaviors. If you are using undocumented API (e.g., use anything in the C++
1258    internal namespace), it can be broken by minor version releases in an
1259    undetermined manner.
1260
1261  Ruby
1262  * When you assign a string field `a.string_field = "X"`, we now call
1263    #encode(UTF-8) on the string and freeze the copy. This saves you from
1264    needing to ensure the string is already encoded as UTF-8. It also prevents
1265    you from mutating the string after it has been assigned (this is how we
1266    ensure it stays valid UTF-8).
1267  * The generated file for `foo.proto` is now `foo_pb.rb` instead of just
1268    `foo.rb`. This makes it easier to see which imports/requires are from
1269    protobuf generated code, and also prevents conflicts with any `foo.rb` file
1270    you might have written directly in Ruby. It is a backward-incompatible
1271    change: you will need to update all of your `require` statements.
1272  * For package names like `foo_bar`, we now translate this to the Ruby module
1273    `FooBar`. This is more idiomatic Ruby than what we used to do (`Foo_bar`).
1274
1275  JavaScript
1276  * Scalar fields like numbers and boolean now return defaults instead of
1277    `undefined` or `null` when they are unset. You can test for presence
1278    explicitly by calling `hasFoo()`, which we now generate for scalar fields.
1279
1280  Java Lite
1281  * Java Lite is now implemented as a separate plugin, maintained in the
1282    `javalite` branch. Both lite runtime and protoc artifacts will be available
1283    in Maven.
1284
1285  C#
1286  * Target platforms now .NET 4.5, selected portable subsets and .NET Core.
1287  * legacy_enum_values option is no longer supported.
1288
12892016-07-15 version 3.0.0-beta-4 (C++/Java/Python/Ruby/Objective-C/C#/JavaScript)
1290  General
1291  * Added a deterministic serialization API for C++. The deterministic
1292    serialization guarantees that given a binary, equal messages will be
1293    serialized to the same bytes. This allows applications like MapReduce to
1294    group equal messages based on the serialized bytes. The deterministic
1295    serialization is, however, NOT canonical across languages; it is also
1296    unstable across different builds with schema changes due to unknown fields.
1297    Users who need canonical serialization, e.g. persistent storage in a
1298    canonical form, fingerprinting, etc, should define their own
1299    canonicalization specification and implement the serializer using reflection
1300    APIs rather than relying on this API.
1301  * Added OneofOptions. You can now define custom options for oneof groups.
1302      import "google/protobuf/descriptor.proto";
1303      extend google.protobuf.OneofOptions {
1304        optional int32 my_oneof_extension = 12345;
1305      }
1306      message Foo {
1307        oneof oneof_group {
1308          (my_oneof_extension) = 54321;
1309          ...
1310        }
1311      }
1312
1313  C++ (beta)
1314  * Introduced a deterministic serialization API in
1315    CodedOutputStream::SetSerializationDeterministic(bool). See the notes about
1316    deterministic serialization in the General section.
1317  * Added google::protobuf::Map::swap() to swap two map fields.
1318  * Fixed a memory leak when calling Reflection::ReleaseMessage() on a message
1319    allocated on arena.
1320  * Improved error reporting when parsing text format protos.
1321  * JSON
1322      - Added a new parser option to ignore unknown fields when parsing JSON.
1323      - Added convenient methods for message to/from JSON conversion.
1324  * Various performance optimizations.
1325
1326  Java (beta)
1327  * File option "java_generate_equals_and_hash" is now deprecated. equals() and
1328    hashCode() methods are generated by default.
1329  * Added a new JSON printer option "omittingInsignificantWhitespace" to produce
1330    a more compact JSON output. The printer will pretty-print by default.
1331  * Updated Java runtime to be compatible with 2.5.0/2.6.1 generated protos.
1332
1333  Python (beta)
1334  * Added support to pretty print Any messages in text format.
1335  * Added a flag to ignore unknown fields when parsing JSON.
1336  * Bugfix: "@type" field of a JSON Any message is now correctly put before
1337    other fields.
1338
1339  Objective-C (beta)
1340  * Updated the code to support compiling with more compiler warnings
1341    enabled. (Issue 1616)
1342  * Exposing more detailed errors for parsing failures. (PR 1623)
1343  * Small (breaking) change to the naming of some methods on the support classes
1344    for map<>. There were collisions with the system provided KVO support, so
1345    the names were changed to avoid those issues.  (PR 1699)
1346  * Fixed for proper Swift bridging of error handling during parsing. (PR 1712)
1347  * Complete support for generating sources that will go into a Framework and
1348    depend on generated sources from other Frameworks. (Issue 1457)
1349
1350  C# (beta)
1351  * RepeatedField optimizations.
1352  * Support for .NET Core.
1353  * Minor bug fixes.
1354  * Ability to format a single value in JsonFormatter (advanced usage only).
1355  * Modifications to attributes applied to generated code.
1356
1357  Javascript (alpha)
1358  * Maps now have a real map API instead of being treated as repeated fields.
1359  * Well-known types are now provided in the google-protobuf package, and the
1360    code generator knows to require() them from that package.
1361  * Bugfix: non-canonical varints are correctly decoded.
1362
1363  Ruby (alpha)
1364  * Accessors for oneof fields now return default values instead of nil.
1365
1366  Java Lite
1367  * Java lite support is removed from protocol compiler. It will be supported
1368    as a protocol compiler plugin in a separate code branch.
1369
13702016-05-16 version 3.0.0-beta-3 (C++/Java/Python/Ruby/Nano/Objective-C/C#/JavaScript)
1371  General
1372  * Supported Proto3 lite-runtime in C++/Java for mobile platforms.
1373  * Any type now supports APIs to specify prefixes other than
1374    type.googleapis.com
1375  * Removed javanano_use_deprecated_package option; Nano will always has its own
1376    ".nano" package.
1377
1378  C++ (Beta)
1379  * Improved hash maps.
1380      - Improved hash maps comments. In particular, please note that equal hash
1381        maps will not necessarily have the same iteration order and
1382        serialization.
1383      - Added a new hash maps implementation that will become the default in a
1384        later release.
1385  * Arenas
1386      - Several inlined methods in Arena were moved to out-of-line to improve
1387        build performance and code size.
1388      - Added SpaceAllocatedAndUsed() to report both space used and allocated
1389      - Added convenient class UnsafeArenaAllocatedRepeatedPtrFieldBackInserter
1390  * Any
1391      - Allow custom type URL prefixes in Any packing.
1392      - TextFormat now expand the Any type rather than printing bytes.
1393  * Performance optimizations and various bug fixes.
1394
1395  Java (Beta)
1396  * Introduced an ExperimentalApi annotation. Annotated APIs are experimental
1397    and are subject to change in a backward incompatible way in future releases.
1398  * Introduced zero-copy serialization as an ExperimentalApi
1399      - Introduction of the `ByteOutput` interface. This is similar to
1400        `OutputStream` but provides semantics for lazy writing (i.e. no
1401        immediate copy required) of fields that are considered to be immutable.
1402      - `ByteString` now supports writing to a `ByteOutput`, which will directly
1403        expose the internals of the `ByteString` (i.e. `byte[]` or `ByteBuffer`)
1404        to the `ByteOutput` without copying.
1405      - `CodedOutputStream` now supports writing to a `ByteOutput`. `ByteString`
1406        instances that are too large to fit in the internal buffer will be
1407        (lazily) written to the `ByteOutput` directly.
1408      - This allows applications using large `ByteString` fields to avoid
1409        duplication of these fields entirely. Such an application can supply a
1410        `ByteOutput` that chains together the chunks received from
1411        `CodedOutputStream` before forwarding them onto the IO system.
1412  * Other related changes to `CodedOutputStream`
1413      - Additional use of `sun.misc.Unsafe` where possible to perform fast
1414        access to `byte[]` and `ByteBuffer` values and avoiding unnecessary
1415        range checking.
1416      - `ByteBuffer`-backed `CodedOutputStream` now writes directly to the
1417        `ByteBuffer` rather than to an intermediate array.
1418  * Improved lite-runtime.
1419      - Lite protos now implement deep equals/hashCode/toString
1420      - Significantly improved the performance of Builder#mergeFrom() and
1421        Builder#mergeDelimitedFrom()
1422  * Various bug fixes and small feature enhancement.
1423      - Fixed stack overflow when in hashCode() for infinite recursive oneofs.
1424      - Fixed the lazy field parsing in lite to merge rather than overwrite.
1425      - TextFormat now supports reporting line/column numbers on errors.
1426      - Updated to add appropriate @Override for better compiler errors.
1427
1428  Python (Beta)
1429  * Added JSON format for Any, Struct, Value and ListValue
1430  * [ ] is now accepted for both repeated scalar fields and repeated message
1431    fields in text format parser.
1432  * Numerical field name is now supported in text format.
1433  * Added DiscardUnknownFields API for python protobuf message.
1434
1435  Objective-C (Beta)
1436  * Proto comments now come over as HeaderDoc comments in the generated sources
1437    so Xcode can pick them up and display them.
1438  * The library headers have been updated to use HeaderDoc comments so Xcode can
1439    pick them up and display them.
1440  * The per message and per field overhead in both generated code and runtime
1441    object sizes was reduced.
1442  * Generated code now include deprecated annotations when the proto file
1443    included them.
1444
1445  C# (Beta)
1446  In general: some changes are breaking, which require regenerating messages.
1447  Most user-written code will not be impacted *except* for the renaming of enum
1448  values.
1449
1450  * Allow custom type URL prefixes in `Any` packing, and ignore them when
1451    unpacking
1452  * `protoc` is now in a separate NuGet package (Google.Protobuf.Tools)
1453  * New option: `internal_access` to generate internal classes
1454  * Enum values are now PascalCased, and if there's a prefix which matches the
1455    name of the enum, that is removed (so an enum `COLOR` with a value
1456    `COLOR_BLUE` would generate a value of just `Blue`). An option
1457    (`legacy_enum_values`) is temporarily available to disable this, but the
1458    option will be removed for GA.
1459  * `json_name` option is now honored
1460  * If group tags are encountered when parsing, they are validated more
1461    thoroughly (although we don't support actual groups)
1462  * NuGet dependencies are better specified
1463  * Breaking: `Preconditions` is renamed to `ProtoPreconditions`
1464  * Breaking: `GeneratedCodeInfo` is renamed to `GeneratedClrTypeInfo`
1465  * `JsonFormatter` now allows writing to a `TextWriter`
1466  * New interface, `ICustomDiagnosticMessage` to allow more compact
1467    representations from `ToString`
1468  * `CodedInputStream` and `CodedOutputStream` now implement `IDisposable`,
1469    which simply disposes of the streams they were constructed with
1470  * Map fields no longer support null values (in line with other languages)
1471  * Improvements in JSON formatting and parsing
1472
1473  Javascript (Alpha)
1474  * Better support for "bytes" fields: bytes fields can be read as either a
1475    base64 string or UInt8Array (in environments where TypedArray is supported).
1476  * New support for CommonJS imports.  This should make it easier to use the
1477    JavaScript support in Node.js and tools like WebPack.  See js/README.md for
1478    more information.
1479  * Some significant internal refactoring to simplify and modularize the code.
1480
1481  Ruby (Alpha)
1482  * JSON serialization now properly uses camelCased names, with a runtime option
1483    that will preserve original names from .proto files instead.
1484  * Well-known types are now included in the distribution.
1485  * Release now includes binary gems for Windows, Mac, and Linux instead of just
1486    source gems.
1487  * Bugfix for serializing oneofs.
1488
1489  C++/Java Lite (Alpha)
1490    A new "lite" generator parameter was introduced in the protoc for C++ and
1491    Java for Proto3 syntax messages. Example usage:
1492
1493     ./protoc --cpp_out=lite:$OUTPUT_PATH foo.proto
1494
1495    The protoc will treat the current input and all the transitive dependencies
1496    as LITE. The same generator parameter must be used to generate the
1497    dependencies.
1498
1499    In Proto3 syntax files, "optimized_for=LITE_RUNTIME" is no longer supported.
1500
1501
15022015-12-30 version 3.0.0-beta-2 (C++/Java/Python/Ruby/Nano/Objective-C/C#/JavaScript)
1503  General
1504  * Introduced a new language implementation: JavaScript.
1505  * Added a new field option "json_name". By default proto field names are
1506    converted to "lowerCamelCase" in proto3 JSON format. This option can be
1507    used to override this behavior and specify a different JSON name for the
1508    field.
1509  * Added conformance tests to ensure implementations are following proto3 JSON
1510    specification.
1511
1512  C++ (Beta)
1513  * Various bug fixes and improvements to the JSON support utility:
1514      - Duplicate map keys in JSON are now rejected (i.e., translation will
1515        fail).
1516      - Fixed wire-format for google.protobuf.Value/ListValue.
1517      - Fixed precision loss when converting google.protobuf.Timestamp.
1518      - Fixed a bug when parsing invalid UTF-8 code points.
1519      - Fixed a memory leak.
1520      - Reduced call stack usage.
1521
1522  Java (Beta)
1523  * Cleaned up some unused methods on CodedOutputStream.
1524  * Presized lists for packed fields during parsing in the lite runtime to
1525    reduce allocations and improve performance.
1526  * Improved the performance of unknown fields in the lite runtime.
1527  * Introduced UnsafeByteStrings to support zero-copy ByteString creation.
1528  * Various bug fixes and improvements to the JSON support utility:
1529      - Fixed a thread-safety bug.
1530      - Added a new option “preservingProtoFieldNames” to JsonFormat.
1531      - Added a new option “includingDefaultValueFields” to JsonFormat.
1532      - Updated the JSON utility to comply with proto3 JSON specification.
1533
1534  Python (Beta)
1535  * Added proto3 JSON format utility. It includes support for all field types
1536    and a few well-known types except for Any and Struct.
1537  * Added runtime support for Any, Timestamp, Duration and FieldMask.
1538  * [ ] is now accepted for repeated scalar fields in text format parser.
1539  * Map fields now have proper O(1) performance for lookup/insert/delete
1540    when using the Python/C++ implementation. They were previously using O(n)
1541    search-based algorithms because the C++ reflection interface didn't
1542    support true map operations.
1543
1544  Objective-C (Beta)
1545  * Various bug-fixes and code tweaks to pass more strict compiler warnings.
1546  * Now has conformance test coverage and is passing all tests.
1547
1548  C# (Beta)
1549  * Various bug-fixes.
1550  * Code generation: Files generated in directories based on namespace.
1551  * Code generation: Include comments from .proto files in XML doc
1552    comments (naively)
1553  * Code generation: Change organization/naming of "reflection class" (access
1554    to file descriptor)
1555  * Code generation and library: Add Parser property to MessageDescriptor,
1556    and introduce a non-generic parser type.
1557  * Library: Added TypeRegistry to support JSON parsing/formatting of Any.
1558  * Library: Added Any.Pack/Unpack support.
1559  * Library: Implemented JSON parsing.
1560
1561  Javascript (Alpha)
1562  * Added proto3 support for JavaScript. The runtime is written in pure
1563    JavaScript and works in browsers and in Node.js. To generate JavaScript
1564    code for your proto, invoke protoc with "--js_out". See js/README.md
1565    for more build instructions.
1566
15672015-08-26 version 3.0.0-beta-1 (C++/Java/Python/Ruby/Nano/Objective-C/C#)
1568  About Beta
1569  * This is the first beta release of protobuf v3.0.0. Not all languages
1570    have reached beta stage. Languages not marked as beta are still in
1571    alpha (i.e., be prepared for API breaking changes).
1572
1573  General
1574  * Proto3 JSON is supported in several languages (fully supported in C++
1575    and Java, partially supported in Ruby/C#). The JSON spec is defined in
1576    the proto3 language guide:
1577
1578      https://developers.google.com/protocol-buffers/docs/proto3#json
1579
1580    We will publish a more detailed spec to define the exact behavior of
1581    proto3-conformant JSON serializers and parsers. Until then, do not rely
1582    on specific behaviors of the implementation if it’s not documented in
1583    the above spec. More specifically, the behavior is not yet finalized for
1584    the following:
1585      - Parsing invalid JSON input (e.g., input with trailing commas).
1586      - Non-camelCase names in JSON input.
1587      - The same field appears multiple times in JSON input.
1588      - JSON arrays contain “null” values.
1589      - The message has unknown fields.
1590
1591  * Proto3 now enforces strict UTF-8 checking. Parsing will fail if a string
1592    field contains non UTF-8 data.
1593
1594  C++ (Beta)
1595  * Introduced new utility functions/classes in the google/protobuf/util
1596    directory:
1597      - MessageDifferencer: compare two proto messages and report their
1598                            differences.
1599      - JsonUtil: support converting protobuf binary format to/from JSON.
1600      - TimeUtil: utility functions to work with well-known types Timestamp
1601                  and Duration.
1602      - FieldMaskUtil: utility functions to work with FieldMask.
1603
1604  * Performance optimization of arena construction and destruction.
1605  * Bug fixes for arena and maps support.
1606  * Changed to use cmake for Windows Visual Studio builds.
1607  * Added Bazel support.
1608
1609  Java (Beta)
1610  * Introduced a new util package that will be distributed as a separate
1611    artifact in maven. It contains:
1612      - JsonFormat: convert proto messages to/from JSON.
1613      - TimeUtil: utility functions to work with Timestamp and Duration.
1614      - FieldMaskUtil: utility functions to work with FieldMask.
1615
1616  * The static PARSER in each generated message is deprecated, and it will
1617    be removed in a future release. A static parser() getter is generated
1618    for each message type instead.
1619  * Performance optimizations for String fields serialization.
1620  * Performance optimizations for Lite runtime on Android:
1621      - Reduced allocations
1622      - Reduced method overhead after ProGuarding
1623      - Reduced code size after ProGuarding
1624
1625  Python (Alpha)
1626  * Removed legacy Python 2.5 support.
1627  * Moved to a single Python 2.x/3.x-compatible codebase, instead of using 2to3.
1628  * Fixed build/tests on Python 2.6, 2.7, 3.3, and 3.4.
1629      - Pure-Python works on all four.
1630      - Python/C++ implementation works on all but 3.4, due to changes in the
1631        Python/C++ API in 3.4.
1632  * Some preliminary work has been done to allow for multiple DescriptorPools
1633    with Python/C++.
1634
1635  Ruby (Alpha)
1636  * Many bugfixes:
1637      - fixed parsing/serialization of bytes, sint, sfixed types
1638      - other parser bugfixes
1639      - fixed memory leak affecting Ruby 2.2
1640
1641  JavaNano (Alpha)
1642  * JavaNano generated code now will be put in a nano package by default to
1643    avoid conflicts with Java generated code.
1644
1645  Objective-C (Alpha)
1646  * Added non-null markup to ObjC library. Requires SDK 8.4+ to build.
1647  * Many bugfixes:
1648      - Removed the class/enum filter.
1649      - Renamed some internal types to avoid conflicts with the well-known types
1650        protos.
1651      - Added missing support for parsing repeated primitive fields in packed or
1652        unpacked forms.
1653      - Added *Count for repeated and map<> fields to avoid auto-create when
1654        checking for them being set.
1655
1656  C# (Alpha)
1657  * Namespace changed to Google.Protobuf (and NuGet package will be named
1658    correspondingly).
1659  * Target platforms now .NET 4.5 and selected portable subsets only.
1660  * Removed lite runtime.
1661  * Reimplementation to use mutable message types.
1662  * Null references used to represent "no value" for message type fields.
1663  * Proto3 semantics supported; proto2 files are prohibited for C# codegen.
1664    Most proto3 features supported:
1665      - JSON formatting (a.k.a. serialization to JSON), including well-known
1666        types (except for Any).
1667      - Wrapper types mapped to nullable value types (or string/ByteString
1668        allowing nullability). JSON parsing is not supported yet.
1669      - maps
1670      - oneof
1671      - enum unknown value preservation
1672
16732015-05-25 version 3.0.0-alpha-3 (Objective-C/C#):
1674  General
1675  * Introduced two new language implementations (Objective-C, C#) to proto3.
1676  * Explicit "optional" keyword are disallowed in proto3 syntax, as fields are
1677    optional by default.
1678  * Group fields are no longer supported in proto3 syntax.
1679  * Changed repeated primitive fields to use packed serialization by default in
1680    proto3 (implemented for C++, Java, Python in this release).  The user can
1681    still disable packed serialization by setting packed to false for now.
1682  * Added well-known type protos (any.proto, empty.proto, timestamp.proto,
1683    duration.proto, etc.). Users can import and use these protos just like
1684    regular proto files. Additional runtime support will be added for them in
1685    future releases (in the form of utility helper functions, or having them
1686    replaced by language specific types in generated code).
1687  * Added a "reserved" keyword in both proto2 and proto3 syntax. User can use
1688    this keyword to declare reserved field numbers and names to prevent them
1689    from being reused by other fields in the same message.
1690
1691    To reserve field numbers, add a reserved declaration in your message:
1692
1693      message TestMessage {
1694        reserved 2, 15, 9 to 11, 3;
1695      }
1696
1697    This reserves field numbers 2, 3, 9, 10, 11 and 15. If a user uses any of
1698    these as field numbers, the protocol buffer compiler will report an error.
1699
1700    Field names can also be reserved:
1701
1702      message TestMessage {
1703        reserved "foo", "bar";
1704      }
1705
1706  * Various bug fixes since 3.0.0-alpha-2
1707
1708  Objective-C
1709    Objective-C includes a code generator and a native objective-c runtime
1710    library.  By adding “--objc_out” to protoc, the code generator will generate
1711    a header(*.pbobjc.h) and an implementation file(*.pbobjc.m) for each proto
1712    file.
1713
1714    In this first release, the generated interface provides: enums, messages,
1715    field support(single, repeated, map, oneof), proto2 and proto3 syntax
1716    support, parsing and serialization. It’s  compatible with ARC and non-ARC
1717    usage. Besides, user can also access it via the swift bridging header.
1718
1719    See objectivec/README.md for details.
1720
1721  C#
1722    * C# protobufs are based on project
1723      https://github.com/jskeet/protobuf-csharp-port. The original project was
1724      frozen and all the new development will happen here.
1725    * Codegen plugin for C# was completely rewritten to C++ and is now an
1726      integral part of protoc.
1727    * Some refactorings and cleanup has been applied to the C# runtime library.
1728    * Only proto2 is supported in C# at the moment, proto3 support is in
1729      progress and will likely bring significant breaking changes to the API.
1730
1731    See csharp/README.md for details.
1732
1733  C++
1734    * Added runtime support for Any type. To use Any in your proto file, first
1735      import the definition of Any:
1736
1737        // foo.proto
1738        import "google/protobuf/any.proto";
1739        message Foo {
1740          google.protobuf.Any any_field = 1;
1741        }
1742        message Bar {
1743          int32 value = 1;
1744        }
1745
1746      Then in C++ you can access the Any field using PackFrom()/UnpackTo()
1747      methods:
1748
1749        Foo foo;
1750        Bar bar = ...;
1751        foo.mutable_any_field()->PackFrom(bar);
1752        ...
1753        if (foo.any_field().IsType<Bar>()) {
1754          foo.any_field().UnpackTo(&bar);
1755          ...
1756        }
1757    * In text format, entries of a map field will be sorted by key.
1758
1759  Java
1760    * Continued optimizations on the lite runtime to improve performance for
1761      Android.
1762
1763  Python
1764    * Added map support.
1765      - maps now have a dict-like interface (msg.map_field[key] = value)
1766      - existing code that modifies maps via the repeated field interface
1767        will need to be updated.
1768
1769  Ruby
1770    * Improvements to RepeatedField's emulation of the Ruby Array API.
1771    * Various speedups and internal cleanups.
1772
17732015-02-26 version 3.0.0-alpha-2 (Python/Ruby/JavaNano):
1774  General
1775  * Introduced three new language implementations (Ruby, JavaNano, and
1776    Python) to proto3.
1777  * Various bug fixes since 3.0.0-alpha-1
1778
1779  Python:
1780    Python has received several updates, most notably support for proto3
1781    semantics in any .proto file that declares syntax="proto3".
1782    Messages declared in proto3 files no longer represent field presence
1783    for scalar fields (number, enums, booleans, or strings).  You can
1784    no longer call HasField() for such fields, and they are serialized
1785    based on whether they have a non-zero/empty/false value.
1786
1787    One other notable change is in the C++-accelerated implementation.
1788    Descriptor objects (which describe the protobuf schema and allow
1789    reflection over it) are no longer duplicated between the Python
1790    and C++ layers.  The Python descriptors are now simple wrappers
1791    around the C++ descriptors.  This change should significantly
1792    reduce the memory usage of programs that use a lot of message
1793    types.
1794
1795  Ruby:
1796    We have added proto3 support for Ruby via a native C extension.
1797
1798    The Ruby extension itself is included in the ruby/ directory, and details on
1799    building and installing the extension are in ruby/README.md. The extension
1800    will also be published as a Ruby gem. Code generator support is included as
1801    part of `protoc` with the `--ruby_out` flag.
1802
1803    The Ruby extension implements a user-friendly DSL to define message types
1804    (also generated by the code generator from `.proto` files).  Once a message
1805    type is defined, the user may create instances of the message that behave in
1806    ways idiomatic to Ruby. For example:
1807
1808    - Message fields are present as ordinary Ruby properties (getter method
1809      `foo` and setter method `foo=`).
1810    - Repeated field elements are stored in a container that acts like a native
1811      Ruby array, and map elements are stored in a container that acts like a
1812      native Ruby hashmap.
1813    - The usual well-known methods, such as `#to_s`, `#dup`, and the like, are
1814      present.
1815
1816    Unlike several existing third-party Ruby extensions for protobuf, this
1817    extension is built on a "strongly-typed" philosophy: message fields and
1818    array/map containers will throw exceptions eagerly when values of the
1819    incorrect type are inserted.
1820
1821    See ruby/README.md for details.
1822
1823  JavaNano:
1824    JavaNano is a special code generator and runtime library designed especially
1825    for resource-restricted systems, like Android. It is very resource-friendly
1826    in both the amount of code and the runtime overhead. Here is an an overview
1827    of JavaNano features compared with the official Java protobuf:
1828
1829    - No descriptors or message builders.
1830    - All messages are mutable; fields are public Java fields.
1831    - For optional fields only, encapsulation behind setter/getter/hazzer/
1832      clearer functions is opt-in, which provide proper 'has' state support.
1833    - For proto2, if not opted in, has state (field presence) is not available.
1834      Serialization outputs all fields not equal to their defaults.
1835      The behavior is consistent with proto3 semantics.
1836    - Required fields (proto2 only) are always serialized.
1837    - Enum constants are integers; protection against invalid values only
1838      when parsing from the wire.
1839    - Enum constants can be generated into container interfaces bearing
1840      the enum's name (so the referencing code is in Java style).
1841    - CodedInputByteBufferNano can only take byte[] (not InputStream).
1842    - Similarly CodedOutputByteBufferNano can only write to byte[].
1843    - Repeated fields are in arrays, not ArrayList or Vector. Null array
1844      elements are allowed and silently ignored.
1845    - Full support for serializing/deserializing repeated packed fields.
1846    - Support  extensions (in proto2).
1847    - Unset messages/groups are null, not an immutable empty default
1848      instance.
1849    - toByteArray(...) and mergeFrom(...) are now static functions of
1850      MessageNano.
1851    - The 'bytes' type translates to the Java type byte[].
1852
1853    See javanano/README.txt for details.
1854
18552014-12-01 version 3.0.0-alpha-1 (C++/Java):
1856
1857  General
1858  * Introduced Protocol Buffers language version 3 (aka proto3).
1859
1860    When protobuf was initially opensourced it implemented Protocol Buffers
1861    language version 2 (aka proto2), which is why the version number
1862    started from v2.0.0. From v3.0.0, a new language version (proto3) is
1863    introduced while the old version (proto2) will continue to be supported.
1864
1865    The main intent of introducing proto3 is to clean up protobuf before
1866    pushing the language as the foundation of Google's new API platform.
1867    In proto3, the language is simplified, both for ease of use and  to
1868    make it available in a wider range of programming languages. At the
1869    same time a few features are added to better support common idioms
1870    found in APIs.
1871
1872    The following are the main new features in language version 3:
1873
1874      1. Removal of field presence logic for primitive value fields, removal
1875         of required fields, and removal of default values. This makes proto3
1876         significantly easier to implement with open struct representations,
1877         as in languages like Android Java, Objective C, or Go.
1878      2. Removal of unknown fields.
1879      3. Removal of extensions, which are instead replaced by a new standard
1880         type called Any.
1881      4. Fix semantics for unknown enum values.
1882      5. Addition of maps.
1883      6. Addition of a small set of standard types for representation of time,
1884         dynamic data, etc.
1885      7. A well-defined encoding in JSON as an alternative to binary proto
1886         encoding.
1887
1888    This release (v3.0.0-alpha-1) includes partial proto3 support for C++ and
1889    Java. Items 6 (well-known types) and 7 (JSON format) in the above feature
1890    list are not implemented.
1891
1892    A new notion "syntax" is introduced to specify whether a .proto file
1893    uses proto2 or proto3:
1894
1895      // foo.proto
1896      syntax = "proto3";
1897      message Bar {...}
1898
1899    If omitted, the protocol compiler will generate a warning and "proto2" will
1900    be used as the default. This warning will be turned into an error in a
1901    future release.
1902
1903    We recommend that new Protocol Buffers users use proto3. However, we do not
1904    generally recommend that existing users migrate from proto2 from proto3 due
1905    to API incompatibility, and we will continue to support proto2 for a long
1906    time.
1907
1908  * Added support for map fields (implemented in C++/Java for both proto2 and
1909    proto3).
1910
1911    Map fields can be declared using the following syntax:
1912
1913      message Foo {
1914        map<string, string> values = 1;
1915      }
1916
1917    Data of a map field will be stored in memory as an unordered map and it
1918    can be accessed through generated accessors.
1919
1920  C++
1921  * Added arena allocation support (for both proto2 and proto3).
1922
1923    Profiling shows memory allocation and deallocation constitutes a significant
1924    fraction of CPU-time spent in protobuf code and arena allocation is a
1925    technique introduced to reduce this cost. With arena allocation, new
1926    objects will be allocated from a large piece of preallocated memory and
1927    deallocation of these objects is almost free. Early adoption shows 20% to
1928    50% improvement in some Google binaries.
1929
1930    To enable arena support, add the following option to your .proto file:
1931
1932      option cc_enable_arenas = true;
1933
1934    Protocol compiler will generate additional code to make the generated
1935    message classes work with arenas. This does not change the existing API
1936    of protobuf messages and does not affect wire format. Your existing code
1937    should continue to work after adding this option. In the future we will
1938    make this option enabled by default.
1939
1940    To actually take advantage of arena allocation, you need to use the arena
1941    APIs when creating messages. A quick example of using the arena API:
1942
1943      {
1944        google::protobuf::Arena arena;
1945        // Allocate a protobuf message in the arena.
1946        MyMessage* message = Arena::CreateMessage<MyMessage>(&arena);
1947        // All submessages will be allocated in the same arena.
1948        if (!message->ParseFromString(data)) {
1949          // Deal with malformed input data.
1950        }
1951        // Must not delete the message here. It will be deleted automatically
1952        // when the arena is destroyed.
1953      }
1954
1955    Currently arena does not work with map fields. Enabling arena in a .proto
1956    file containing map fields will result in compile errors in the generated
1957    code. This will be addressed in a future release.
1958
19592014-10-20 version 2.6.1:
1960
1961  C++
1962  * Added atomicops support for Solaris.
1963  * Released memory allocated by InitializeDefaultRepeatedFields() and
1964    GetEmptyString(). Some memory sanitizers reported them as memory leaks.
1965
1966  Java
1967  * Updated DynamicMessage.setField() to handle repeated enum values
1968    correctly.
1969  * Fixed a bug that caused NullPointerException to be thrown when
1970    converting manually constructed FileDescriptorProto to
1971    FileDescriptor.
1972
1973  Python
1974  * Fixed WhichOneof() to work with de-serialized protobuf messages.
1975  * Fixed a missing file problem of Python C++ implementation.
1976
19772014-08-15 version 2.6.0:
1978
1979  General
1980  * Added oneofs(unions) feature. Fields in the same oneof will share
1981    memory and at most one field can be set at the same time. Use the
1982    oneof keyword to define a oneof like:
1983      message SampleMessage {
1984        oneof test_oneof {
1985          string name = 4;
1986          YourMessage sub_message = 9;
1987        }
1988      }
1989  * Files, services, enums, messages, methods and enum values can be marked
1990    as deprecated now.
1991  * Added Support for list values, including lists of messages, when
1992    parsing text-formatted protos in C++ and Java.
1993      For example:  foo: [1, 2, 3]
1994
1995  C++
1996  * Enhanced customization on TestFormat printing.
1997  * Added SwapFields() in reflection API to swap a subset of fields.
1998    Added SetAllocatedMessage() in reflection API.
1999  * Repeated primitive extensions are now packable. The
2000    [packed=true] option only affects serializers. Therefore, it is
2001    possible to switch a repeated extension field to packed format
2002    without breaking backwards-compatibility.
2003  * Various speed optimizations.
2004
2005  Java
2006  * writeTo() method in ByteString can now write a substring to an
2007    output stream. Added endWith() method for ByteString.
2008  * ByteString and ByteBuffer are now supported in CodedInputStream
2009    and CodedOutputStream.
2010  * java_generate_equals_and_hash can now be used with the LITE_RUNTIME.
2011
2012  Python
2013  * A new C++-backed extension module (aka "cpp api v2") that replaces the
2014    old ("cpp api v1") one.  Much faster than the pure Python code.  This one
2015    resolves many bugs and is recommended for general use over the
2016    pure Python when possible.
2017  * Descriptors now have enum_types_by_name and extension_types_by_name dict
2018    attributes.
2019  * Support for Python 3.
2020
20212013-02-27 version 2.5.0:
2022
2023  General
2024  * New notion "import public" that allows a proto file to forward the content
2025    it imports to its importers. For example,
2026      // foo.proto
2027      import public "bar.proto";
2028      import "baz.proto";
2029
2030      // qux.proto
2031      import "foo.proto";
2032      // Stuff defined in bar.proto may be used in this file, but stuff from
2033      // baz.proto may NOT be used without importing it explicitly.
2034    This is useful for moving proto files. To move a proto file, just leave
2035    a single "import public" in the old proto file.
2036  * New enum option "allow_alias" that specifies whether different symbols can
2037    be assigned the same numeric value. Default value is "true". Setting it to
2038    false causes the compiler to reject enum definitions where multiple symbols
2039    have the same numeric value.
2040    Note: We plan to flip the default value to "false" in a future release.
2041    Projects using enum aliases should set the option to "true" in their .proto
2042    files.
2043
2044  C++
2045  * New generated method set_allocated_foo(Type* foo) for message and string
2046    fields. This method allows you to set the field to a pre-allocated object
2047    and the containing message takes the ownership of that object.
2048  * Added SetAllocatedExtension() and ReleaseExtension() to extensions API.
2049  * Custom options are now formatted correctly when descriptors are printed in
2050    text format.
2051  * Various speed optimizations.
2052
2053  Java
2054  * Comments in proto files are now collected and put into generated code as
2055    comments for corresponding classes and data members.
2056  * Added Parser to parse directly into messages without a Builder. For
2057    example,
2058      Foo foo = Foo.PARSER.ParseFrom(input);
2059    Using Parser is ~25% faster than using Builder to parse messages.
2060  * Added getters/setters to access the underlying ByteString of a string field
2061    directly.
2062  * ByteString now supports more operations: substring(), prepend(), and
2063    append(). The implementation of ByteString uses a binary tree structure
2064    to support these operations efficiently.
2065  * New method findInitializationErrors() that lists all missing required
2066    fields.
2067  * Various code size and speed optimizations.
2068
2069  Python
2070  * Added support for dynamic message creation. DescriptorDatabase,
2071    DescriptorPool, and MessageFactory work like their C++ counterparts to
2072    simplify Descriptor construction from *DescriptorProtos, and MessageFactory
2073    provides a message instance from a Descriptor.
2074  * Added pickle support for protobuf messages.
2075  * Unknown fields are now preserved after parsing.
2076  * Fixed bug where custom options were not correctly populated. Custom
2077    options can be accessed now.
2078  * Added EnumTypeWrapper that provides better accessibility to enum types.
2079  * Added ParseMessage(descriptor, bytes) to generate a new Message instance
2080    from a descriptor and a byte string.
2081
20822011-05-01 version 2.4.1:
2083
2084  C++
2085  * Fixed the friendship problem for old compilers to make the library now gcc 3
2086    compatible again.
2087  * Fixed vcprojects/extract_includes.bat to extract compiler/plugin.h.
2088
2089  Java
2090  * Removed usages of JDK 1.6 only features to make the library now JDK 1.5
2091    compatible again.
2092  * Fixed a bug about negative enum values.
2093  * serialVersionUID is now defined in generated messages for java serializing.
2094  * Fixed protoc to use java.lang.Object, which makes "Object" now a valid
2095    message name again.
2096
2097  Python
2098  * Experimental C++ implementation now requires C++ protobuf library installed.
2099    See the README.txt in the python directory for details.
2100
21012011-02-02 version 2.4.0:
2102
2103  General
2104  * The RPC (cc|java|py)_generic_services default value is now false instead of
2105    true.
2106  * Custom options can have aggregate types. For example,
2107      message MyOption {
2108        optional string comment = 1;
2109        optional string author = 2;
2110      }
2111      extend google.protobuf.FieldOptions {
2112        optional MyOption myoption = 12345;
2113      }
2114    This option can now be set as follows:
2115      message SomeType {
2116        optional int32 field = 1 [(myoption) = { comment:'x' author:'y' }];
2117      }
2118
2119  C++
2120  * Various speed and code size optimizations.
2121  * Added a release_foo() method on string and message fields.
2122  * Fixed gzip_output_stream sub-stream handling.
2123
2124  Java
2125  * Builders now maintain sub-builders for sub-messages. Use getFooBuilder() to
2126    get the builder for the sub-message "foo". This allows you to repeatedly
2127    modify deeply-nested sub-messages without rebuilding them.
2128  * Builder.build() no longer invalidates the Builder for generated messages
2129    (You may continue to modify it and then build another message).
2130  * Code generator will generate efficient equals() and hashCode()
2131    implementations if new option java_generate_equals_and_hash is enabled.
2132    (Otherwise, reflection-based implementations are used.)
2133  * Generated messages now implement Serializable.
2134  * Fields with [deprecated=true] will be marked with @Deprecated in Java.
2135  * Added lazy conversion of UTF-8 encoded strings to String objects to improve
2136    performance.
2137  * Various optimizations.
2138  * Enum value can be accessed directly, instead of calling getNumber() on the
2139    enum member.
2140  * For each enum value, an integer constant is also generated with the suffix
2141    _VALUE.
2142
2143  Python
2144  * Added an experimental  C++ implementation for Python messages via a Python
2145    extension. Implementation type is controlled by an environment variable
2146    PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION (valid values: "cpp" and "python")
2147    The default value is currently "python" but will be changed to "cpp" in
2148    future release.
2149  * Improved performance on message instantiation significantly.
2150    Most of the work on message instantiation is done just once per message
2151    class, instead of once per message instance.
2152  * Improved performance on text message parsing.
2153  * Allow add() to forward keyword arguments to the concrete class.
2154      E.g. instead of
2155        item = repeated_field.add()
2156        item.foo = bar
2157        item.baz = quux
2158      You can do:
2159        repeated_field.add(foo=bar, baz=quux)
2160  * Added a sort() interface to the BaseContainer.
2161  * Added an extend() method to repeated composite fields.
2162  * Added UTF8 debug string support.
2163
21642010-01-08 version 2.3.0:
2165
2166  General
2167  * Parsers for repeated numeric fields now always accept both packed and
2168    unpacked input.  The [packed=true] option only affects serializers.
2169    Therefore, it is possible to switch a field to packed format without
2170    breaking backwards-compatibility -- as long as all parties are using
2171    protobuf 2.3.0 or above, at least.
2172  * The generic RPC service code generated by the C++, Java, and Python
2173    generators can be disabled via file options:
2174      option cc_generic_services = false;
2175      option java_generic_services = false;
2176      option py_generic_services = false;
2177    This allows plugins to generate alternative code, possibly specific to some
2178    particular RPC implementation.
2179
2180  protoc
2181  * Now supports a plugin system for code generators.  Plugins can generate
2182    code for new languages or inject additional code into the output of other
2183    code generators.  Plugins are just binaries which accept a protocol buffer
2184    on stdin and write a protocol buffer to stdout, so they may be written in
2185    any language.  See src/google/protobuf/compiler/plugin.proto.
2186    **WARNING**:  Plugins are experimental.  The interface may change in a
2187    future version.
2188  * If the output location ends in .zip or .jar, protoc will write its output
2189    to a zip/jar archive instead of a directory.  For example:
2190      protoc --java_out=myproto_srcs.jar --python_out=myproto.zip myproto.proto
2191    Currently the archive contents are not compressed, though this could change
2192    in the future.
2193  * inf, -inf, and nan can now be used as default values for float and double
2194    fields.
2195
2196  C++
2197  * Various speed and code size optimizations.
2198  * DynamicMessageFactory is now fully thread-safe.
2199  * Message::Utf8DebugString() method is like DebugString() but avoids escaping
2200    UTF-8 bytes.
2201  * Compiled-in message types can now contain dynamic extensions, through use
2202    of CodedInputStream::SetExtensionRegistry().
2203  * Now compiles shared libraries (DLLs) by default on Cygwin and MinGW, to
2204    match other platforms.  Use --disable-shared to avoid this.
2205
2206  Java
2207  * parseDelimitedFrom() and mergeDelimitedFrom() now detect EOF and return
2208    false/null instead of throwing an exception.
2209  * Fixed some initialization ordering bugs.
2210  * Fixes for OpenJDK 7.
2211
2212  Python
2213  * 10-25 times faster than 2.2.0, still pure-Python.
2214  * Calling a mutating method on a sub-message always instantiates the message
2215    in its parent even if the mutating method doesn't actually mutate anything
2216    (e.g. parsing from an empty string).
2217  * Expanded descriptors a bit.
2218
22192009-08-11 version 2.2.0:
2220
2221  C++
2222  * Lite mode:  The "optimize_for = LITE_RUNTIME" option causes the compiler
2223    to generate code which only depends libprotobuf-lite, which is much smaller
2224    than libprotobuf but lacks descriptors, reflection, and some other features.
2225  * Fixed bug where Message.Swap(Message) was only implemented for
2226    optimize_for_speed.  Swap now properly implemented in both modes
2227    (Issue 91).
2228  * Added RemoveLast and SwapElements(index1, index2) to Reflection
2229    interface for repeated elements.
2230  * Added Swap(Message) to Reflection interface.
2231  * Floating-point literals in generated code that are intended to be
2232    single-precision now explicitly have 'f' suffix to avoid pedantic warnings
2233    produced by some compilers.
2234  * The [deprecated=true] option now causes the C++ code generator to generate
2235    a GCC-style deprecation annotation (no-op on other compilers).
2236  * google::protobuf::GetEnumDescriptor<SomeGeneratedEnumType>() returns the
2237    EnumDescriptor for that type -- useful for templates which cannot call
2238    SomeGeneratedEnumType_descriptor().
2239  * Various optimizations and obscure bug fixes.
2240
2241  Java
2242  * Lite mode:  The "optimize_for = LITE_RUNTIME" option causes the compiler
2243    to generate code which only depends libprotobuf-lite, which is much smaller
2244    than libprotobuf but lacks descriptors, reflection, and some other features.
2245  * Lots of style cleanups.
2246
2247  Python
2248  * Fixed endianness bug with floats and doubles.
2249  * Text format parsing support.
2250  * Fix bug with parsing packed repeated fields in embedded messages.
2251  * Ability to initialize fields by passing keyword args to constructor.
2252  * Support iterators in extend and __setslice__ for containers.
2253
22542009-05-13 version 2.1.0:
2255
2256  General
2257  * Repeated fields of primitive types (types other that string, group, and
2258    nested messages) may now use the option [packed = true] to get a more
2259    efficient encoding.  In the new encoding, the entire list is written
2260    as a single byte blob using the "length-delimited" wire type.  Within
2261    this blob, the individual values are encoded the same way they would
2262    be normally except without a tag before each value (thus, they are
2263    tightly "packed").
2264  * For each field, the generated code contains an integer constant assigned
2265    to the field number.  For example, the .proto file:
2266      message Foo { optional int bar_baz = 123; }
2267    would generate the following constants, all with the integer value 123:
2268      C++:     Foo::kBarBazFieldNumber
2269      Java:    Foo.BAR_BAZ_FIELD_NUMBER
2270      Python:  Foo.BAR_BAZ_FIELD_NUMBER
2271    Constants are also generated for extensions, with the same naming scheme.
2272    These constants may be used as switch cases.
2273  * Updated bundled Google Test to version 1.3.0.  Google Test is now bundled
2274    in its verbatim form as a nested autoconf package, so you can drop in any
2275    other version of Google Test if needed.
2276  * optimize_for = SPEED is now the default, by popular demand.  Use
2277    optimize_for = CODE_SIZE if code size is more important in your app.
2278  * It is now an error to define a default value for a repeated field.
2279    Previously, this was silently ignored (it had no effect on the generated
2280    code).
2281  * Fields can now be marked deprecated like:
2282      optional int32 foo = 1 [deprecated = true];
2283    Currently this does not have any actual effect, but in the future the code
2284    generators may generate deprecation annotations in each language.
2285  * Cross-compiling should now be possible using the --with-protoc option to
2286    configure.  See README.txt for more info.
2287
2288  protoc
2289  * --error_format=msvs option causes errors to be printed in Visual Studio
2290    format, which should allow them to be clicked on in the build log to go
2291    directly to the error location.
2292  * The type name resolver will no longer resolve type names to fields.  For
2293    example, this now works:
2294      message Foo {}
2295      message Bar {
2296        optional int32 Foo = 1;
2297        optional Foo baz = 2;
2298      }
2299    Previously, the type of "baz" would resolve to "Bar.Foo", and you'd get
2300    an error because Bar.Foo is a field, not a type.  Now the type of "baz"
2301    resolves to the message type Foo.  This change is unlikely to make a
2302    difference to anyone who follows the Protocol Buffers style guide.
2303
2304  C++
2305  * Several optimizations, including but not limited to:
2306    - Serialization, especially to flat arrays, is 10%-50% faster, possibly
2307      more for small objects.
2308    - Several descriptor operations which previously required locking no longer
2309      do.
2310    - Descriptors are now constructed lazily on first use, rather than at
2311      process startup time.  This should save memory in programs which do not
2312      use descriptors or reflection.
2313    - UnknownFieldSet completely redesigned to be more efficient (especially in
2314      terms of memory usage).
2315    - Various optimizations to reduce code size (though the serialization speed
2316      optimizations increased code size).
2317  * Message interface has method ParseFromBoundedZeroCopyStream() which parses
2318    a limited number of bytes from an input stream rather than parsing until
2319    EOF.
2320  * GzipInputStream and GzipOutputStream support reading/writing gzip- or
2321    zlib-compressed streams if zlib is available.
2322    (google/protobuf/io/gzip_stream.h)
2323  * DescriptorPool::FindAllExtensions() and corresponding
2324    DescriptorDatabase::FindAllExtensions() can be used to enumerate all
2325    extensions of a given type.
2326  * For each enum type Foo, protoc will generate functions:
2327      const string& Foo_Name(Foo value);
2328      bool Foo_Parse(const string& name, Foo* result);
2329    The former returns the name of the enum constant corresponding to the given
2330    value while the latter finds the value corresponding to a name.
2331  * RepeatedField and RepeatedPtrField now have back-insertion iterators.
2332  * String fields now have setters that take a char* and a size, in addition
2333    to the existing ones that took char* or const string&.
2334  * DescriptorPool::AllowUnknownDependencies() may be used to tell
2335    DescriptorPool to create placeholder descriptors for unknown entities
2336    referenced in a FileDescriptorProto.  This can allow you to parse a .proto
2337    file without having access to other .proto files that it imports, for
2338    example.
2339  * Updated gtest to latest version.  The gtest package is now included as a
2340    nested autoconf package, so it should be able to drop new versions into the
2341    "gtest" subdirectory without modification.
2342
2343  Java
2344  * Fixed bug where Message.mergeFrom(Message) failed to merge extensions.
2345  * Message interface has new method toBuilder() which is equivalent to
2346    newBuilderForType().mergeFrom(this).
2347  * All enums now implement the ProtocolMessageEnum interface.
2348  * Setting a field to null now throws NullPointerException.
2349  * Fixed tendency for TextFormat's parsing to overflow the stack when
2350    parsing large string values.  The underlying problem is with Java's
2351    regex implementation (which unfortunately uses recursive backtracking
2352    rather than building an NFA).  Worked around by making use of possessive
2353    quantifiers.
2354  * Generated service classes now also generate pure interfaces.  For a service
2355    Foo, Foo.Interface is a pure interface containing all of the service's
2356    defined methods.  Foo.newReflectiveService() can be called to wrap an
2357    instance of this interface in a class that implements the generic
2358    RpcService interface, which provides reflection support that is usually
2359    needed by RPC server implementations.
2360  * RPC interfaces now support blocking operation in addition to non-blocking.
2361    The protocol compiler generates separate blocking and non-blocking stubs
2362    which operate against separate blocking and non-blocking RPC interfaces.
2363    RPC implementations will have to implement the new interfaces in order to
2364    support blocking mode.
2365  * New I/O methods parseDelimitedFrom(), mergeDelimitedFrom(), and
2366    writeDelimitedTo() read and write "delimited" messages from/to a stream,
2367    meaning that the message size precedes the data.  This way, you can write
2368    multiple messages to a stream without having to worry about delimiting
2369    them yourself.
2370  * Throw a more descriptive exception when build() is double-called.
2371  * Add a method to query whether CodedInputStream is at the end of the input
2372    stream.
2373  * Add a method to reset a CodedInputStream's size counter; useful when
2374    reading many messages with the same stream.
2375  * equals() and hashCode() now account for unknown fields.
2376
2377  Python
2378  * Added slicing support for repeated scalar fields. Added slice retrieval and
2379    removal of repeated composite fields.
2380  * Updated RPC interfaces to allow for blocking operation.  A client may
2381    now pass None for a callback when making an RPC, in which case the
2382    call will block until the response is received, and the response
2383    object will be returned directly to the caller.  This interface change
2384    cannot be used in practice until RPC implementations are updated to
2385    implement it.
2386  * Changes to input_stream.py should make protobuf compatible with appengine.
2387
23882008-11-25 version 2.0.3:
2389
2390  protoc
2391  * Enum values may now have custom options, using syntax similar to field
2392    options.
2393  * Fixed bug where .proto files which use custom options but don't actually
2394    define them (i.e. they import another .proto file defining the options)
2395    had to explicitly import descriptor.proto.
2396  * Adjacent string literals in .proto files will now be concatenated, like in
2397    C.
2398  * If an input file is a Windows absolute path (e.g. "C:\foo\bar.proto") and
2399    the import path only contains "." (or contains "." but does not contain
2400    the file), protoc incorrectly thought that the file was under ".", because
2401    it thought that the path was relative (since it didn't start with a slash).
2402    This has been fixed.
2403
2404  C++
2405  * Generated message classes now have a Swap() method which efficiently swaps
2406    the contents of two objects.
2407  * All message classes now have a SpaceUsed() method which returns an estimate
2408    of the number of bytes of allocated memory currently owned by the object.
2409    This is particularly useful when you are reusing a single message object
2410    to improve performance but want to make sure it doesn't bloat up too large.
2411  * New method Message::SerializeAsString() returns a string containing the
2412    serialized data.  May be more convenient than calling
2413    SerializeToString(string*).
2414  * In debug mode, log error messages when string-type fields are found to
2415    contain bytes that are not valid UTF-8.
2416  * Fixed bug where a message with multiple extension ranges couldn't parse
2417    extensions.
2418  * Fixed bug where MergeFrom(const Message&) didn't do anything if invoked on
2419    a message that contained no fields (but possibly contained extensions).
2420  * Fixed ShortDebugString() to not be O(n^2).  Durr.
2421  * Fixed crash in TextFormat parsing if the first token in the input caused a
2422    tokenization error.
2423  * Fixed obscure bugs in zero_copy_stream_impl.cc.
2424  * Added support for HP C++ on Tru64.
2425  * Only build tests on "make check", not "make".
2426  * Fixed alignment issue that caused crashes when using DynamicMessage on
2427    64-bit Sparc machines.
2428  * Simplify template usage to work with MSVC 2003.
2429  * Work around GCC 4.3.x x86_64 compiler bug that caused crashes on startup.
2430    (This affected Fedora 9 in particular.)
2431  * Now works on "Solaris 10 using recent Sun Studio".
2432
2433  Java
2434  * New overload of mergeFrom() which parses a slice of a byte array instead
2435    of the whole thing.
2436  * New method ByteString.asReadOnlyByteBuffer() does what it sounds like.
2437  * Improved performance of isInitialized() when optimizing for code size.
2438
2439  Python
2440  * Corrected ListFields() signature in Message base class to match what
2441    subclasses actually implement.
2442  * Some minor refactoring.
2443  * Don't pass self as first argument to superclass constructor (no longer
2444    allowed in Python 2.6).
2445
24462008-09-29 version 2.0.2:
2447
2448  General
2449  * License changed from Apache 2.0 to 3-Clause BSD.
2450  * It is now possible to define custom "options", which are basically
2451    annotations which may be placed on definitions in a .proto file.
2452    For example, you might define a field option called "foo" like so:
2453      import "google/protobuf/descriptor.proto"
2454      extend google.protobuf.FieldOptions {
2455        optional string foo = 12345;
2456      }
2457    Then you annotate a field using the "foo" option:
2458      message MyMessage {
2459        optional int32 some_field = 1 [(foo) = "bar"]
2460      }
2461    The value of this option is then visible via the message's
2462    Descriptor:
2463      const FieldDescriptor* field =
2464        MyMessage::descriptor()->FindFieldByName("some_field");
2465      assert(field->options().GetExtension(foo) == "bar");
2466    This feature has been implemented and tested in C++ and Java.
2467    Other languages may or may not need to do extra work to support
2468    custom options, depending on how they construct descriptors.
2469
2470  C++
2471  * Fixed some GCC warnings that only occur when using -pedantic.
2472  * Improved static initialization code, making ordering more
2473    predictable among other things.
2474  * TextFormat will no longer accept messages which contain multiple
2475    instances of a singular field.  Previously, the latter instance
2476    would overwrite the former.
2477  * Now works on systems that don't have hash_map.
2478
2479  Java
2480  * Print @Override annotation in generated code where appropriate.
2481
2482  Python
2483  * Strings now use the "unicode" type rather than the "str" type.
2484    String fields may still be assigned ASCII "str" values; they will
2485    automatically be converted.
2486  * Adding a property to an object representing a repeated field now
2487    raises an exception.  For example:
2488      # No longer works (and never should have).
2489      message.some_repeated_field.foo = 1
2490
2491  Windows
2492  * We now build static libraries rather than DLLs by default on MSVC.
2493    See vsprojects/readme.txt for more information.
2494
24952008-08-15 version 2.0.1:
2496
2497  protoc
2498  * New flags --encode and --decode can be used to convert between protobuf text
2499    format and binary format from the command-line.
2500  * New flag --descriptor_set_out can be used to write FileDescriptorProtos for
2501    all parsed files directly into a single output file.  This is particularly
2502    useful if you wish to parse .proto files from programs written in languages
2503    other than C++: just run protoc as a background process and have it output
2504    a FileDescriptorList, then parse that natively.
2505  * Improved error message when an enum value's name conflicts with another
2506    symbol defined in the enum type's scope, e.g. if two enum types declared
2507    in the same scope have values with the same name.  This is disallowed for
2508    compatibility with C++, but this wasn't clear from the error.
2509  * Fixed absolute output paths on Windows.
2510  * Allow trailing slashes in --proto_path mappings.
2511
2512  C++
2513  * Reflection objects are now per-class rather than per-instance.  To make this
2514    possible, the Reflection interface had to be changed such that all methods
2515    take the Message instance as a parameter.  This change improves performance
2516    significantly in memory-bandwidth-limited use cases, since it makes the
2517    message objects smaller.  Note that source-incompatible interface changes
2518    like this will not be made again after the library leaves beta.
2519  * Heuristically detect sub-messages when printing unknown fields.
2520  * Fix static initialization ordering bug that caused crashes at startup when
2521    compiling on Mac with static linking.
2522  * Fixed TokenizerTest when compiling with -DNDEBUG on Linux.
2523  * Fixed incorrect definition of kint32min.
2524  * Fix bytes type setter to work with byte sequences with embedded NULLs.
2525  * Other irrelevant tweaks.
2526
2527  Java
2528  * Fixed UnknownFieldSet's parsing of varints larger than 32 bits.
2529  * Fixed TextFormat's parsing of "inf" and "nan".
2530  * Fixed TextFormat's parsing of comments.
2531  * Added info to Java POM that will be required when we upload the
2532    package to a Maven repo.
2533
2534  Python
2535  * MergeFrom(message) and CopyFrom(message) are now implemented.
2536  * SerializeToString() raises an exception if the message is missing required
2537    fields.
2538  * Code organization improvements.
2539  * Fixed doc comments for RpcController and RpcChannel, which had somehow been
2540    swapped.
2541  * Fixed text_format_test on Windows where floating-point exponents sometimes
2542    contain extra zeros.
2543  * Fix Python service CallMethod() implementation.
2544
2545  Other
2546  * Improved readmes.
2547  * VIM syntax highlighting improvements.
2548
25492008-07-07 version 2.0.0:
2550
2551  * First public release.
2552