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1// Copyright 2011 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// Tests for template execution, copied from text/template.
6
7package template
8
9import (
10	"bytes"
11	"errors"
12	"flag"
13	"fmt"
14	"io"
15	"reflect"
16	"strings"
17	"sync"
18	"testing"
19	"text/template"
20)
21
22var debug = flag.Bool("debug", false, "show the errors produced by the tests")
23
24// T has lots of interesting pieces to use to test execution.
25type T struct {
26	// Basics
27	True        bool
28	I           int
29	U16         uint16
30	X, S        string
31	FloatZero   float64
32	ComplexZero complex128
33	// Nested structs.
34	U *U
35	// Struct with String method.
36	V0     V
37	V1, V2 *V
38	// Struct with Error method.
39	W0     W
40	W1, W2 *W
41	// Slices
42	SI      []int
43	SICap   []int
44	SIEmpty []int
45	SB      []bool
46	// Arrays
47	AI [3]int
48	// Maps
49	MSI      map[string]int
50	MSIone   map[string]int // one element, for deterministic output
51	MSIEmpty map[string]int
52	MXI      map[any]int
53	MII      map[int]int
54	MI32S    map[int32]string
55	MI64S    map[int64]string
56	MUI32S   map[uint32]string
57	MUI64S   map[uint64]string
58	MI8S     map[int8]string
59	MUI8S    map[uint8]string
60	SMSI     []map[string]int
61	// Empty interfaces; used to see if we can dig inside one.
62	Empty0 any // nil
63	Empty1 any
64	Empty2 any
65	Empty3 any
66	Empty4 any
67	// Non-empty interfaces.
68	NonEmptyInterface         I
69	NonEmptyInterfacePtS      *I
70	NonEmptyInterfaceNil      I
71	NonEmptyInterfaceTypedNil I
72	// Stringer.
73	Str fmt.Stringer
74	Err error
75	// Pointers
76	PI  *int
77	PS  *string
78	PSI *[]int
79	NIL *int
80	// Function (not method)
81	BinaryFunc      func(string, string) string
82	VariadicFunc    func(...string) string
83	VariadicFuncInt func(int, ...string) string
84	NilOKFunc       func(*int) bool
85	ErrFunc         func() (string, error)
86	PanicFunc       func() string
87	// Template to test evaluation of templates.
88	Tmpl *Template
89	// Unexported field; cannot be accessed by template.
90	unexported int
91}
92
93type S []string
94
95func (S) Method0() string {
96	return "M0"
97}
98
99type U struct {
100	V string
101}
102
103type V struct {
104	j int
105}
106
107func (v *V) String() string {
108	if v == nil {
109		return "nilV"
110	}
111	return fmt.Sprintf("<%d>", v.j)
112}
113
114type W struct {
115	k int
116}
117
118func (w *W) Error() string {
119	if w == nil {
120		return "nilW"
121	}
122	return fmt.Sprintf("[%d]", w.k)
123}
124
125var siVal = I(S{"a", "b"})
126
127var tVal = &T{
128	True:   true,
129	I:      17,
130	U16:    16,
131	X:      "x",
132	S:      "xyz",
133	U:      &U{"v"},
134	V0:     V{6666},
135	V1:     &V{7777}, // leave V2 as nil
136	W0:     W{888},
137	W1:     &W{999}, // leave W2 as nil
138	SI:     []int{3, 4, 5},
139	SICap:  make([]int, 5, 10),
140	AI:     [3]int{3, 4, 5},
141	SB:     []bool{true, false},
142	MSI:    map[string]int{"one": 1, "two": 2, "three": 3},
143	MSIone: map[string]int{"one": 1},
144	MXI:    map[any]int{"one": 1},
145	MII:    map[int]int{1: 1},
146	MI32S:  map[int32]string{1: "one", 2: "two"},
147	MI64S:  map[int64]string{2: "i642", 3: "i643"},
148	MUI32S: map[uint32]string{2: "u322", 3: "u323"},
149	MUI64S: map[uint64]string{2: "ui642", 3: "ui643"},
150	MI8S:   map[int8]string{2: "i82", 3: "i83"},
151	MUI8S:  map[uint8]string{2: "u82", 3: "u83"},
152	SMSI: []map[string]int{
153		{"one": 1, "two": 2},
154		{"eleven": 11, "twelve": 12},
155	},
156	Empty1:                    3,
157	Empty2:                    "empty2",
158	Empty3:                    []int{7, 8},
159	Empty4:                    &U{"UinEmpty"},
160	NonEmptyInterface:         &T{X: "x"},
161	NonEmptyInterfacePtS:      &siVal,
162	NonEmptyInterfaceTypedNil: (*T)(nil),
163	Str:                       bytes.NewBuffer([]byte("foozle")),
164	Err:                       errors.New("erroozle"),
165	PI:                        newInt(23),
166	PS:                        newString("a string"),
167	PSI:                       newIntSlice(21, 22, 23),
168	BinaryFunc:                func(a, b string) string { return fmt.Sprintf("[%s=%s]", a, b) },
169	VariadicFunc:              func(s ...string) string { return fmt.Sprint("<", strings.Join(s, "+"), ">") },
170	VariadicFuncInt:           func(a int, s ...string) string { return fmt.Sprint(a, "=<", strings.Join(s, "+"), ">") },
171	NilOKFunc:                 func(s *int) bool { return s == nil },
172	ErrFunc:                   func() (string, error) { return "bla", nil },
173	PanicFunc:                 func() string { panic("test panic") },
174	Tmpl:                      Must(New("x").Parse("test template")), // "x" is the value of .X
175}
176
177var tSliceOfNil = []*T{nil}
178
179// A non-empty interface.
180type I interface {
181	Method0() string
182}
183
184var iVal I = tVal
185
186// Helpers for creation.
187func newInt(n int) *int {
188	return &n
189}
190
191func newString(s string) *string {
192	return &s
193}
194
195func newIntSlice(n ...int) *[]int {
196	p := new([]int)
197	*p = make([]int, len(n))
198	copy(*p, n)
199	return p
200}
201
202// Simple methods with and without arguments.
203func (t *T) Method0() string {
204	return "M0"
205}
206
207func (t *T) Method1(a int) int {
208	return a
209}
210
211func (t *T) Method2(a uint16, b string) string {
212	return fmt.Sprintf("Method2: %d %s", a, b)
213}
214
215func (t *T) Method3(v any) string {
216	return fmt.Sprintf("Method3: %v", v)
217}
218
219func (t *T) Copy() *T {
220	n := new(T)
221	*n = *t
222	return n
223}
224
225func (t *T) MAdd(a int, b []int) []int {
226	v := make([]int, len(b))
227	for i, x := range b {
228		v[i] = x + a
229	}
230	return v
231}
232
233var myError = errors.New("my error")
234
235// MyError returns a value and an error according to its argument.
236func (t *T) MyError(error bool) (bool, error) {
237	if error {
238		return true, myError
239	}
240	return false, nil
241}
242
243// A few methods to test chaining.
244func (t *T) GetU() *U {
245	return t.U
246}
247
248func (u *U) TrueFalse(b bool) string {
249	if b {
250		return "true"
251	}
252	return ""
253}
254
255func typeOf(arg any) string {
256	return fmt.Sprintf("%T", arg)
257}
258
259type execTest struct {
260	name   string
261	input  string
262	output string
263	data   any
264	ok     bool
265}
266
267// bigInt and bigUint are hex string representing numbers either side
268// of the max int boundary.
269// We do it this way so the test doesn't depend on ints being 32 bits.
270var (
271	bigInt  = fmt.Sprintf("0x%x", int(1<<uint(reflect.TypeFor[int]().Bits()-1)-1))
272	bigUint = fmt.Sprintf("0x%x", uint(1<<uint(reflect.TypeFor[int]().Bits()-1)))
273)
274
275var execTests = []execTest{
276	// Trivial cases.
277	{"empty", "", "", nil, true},
278	{"text", "some text", "some text", nil, true},
279	{"nil action", "{{nil}}", "", nil, false},
280
281	// Ideal constants.
282	{"ideal int", "{{typeOf 3}}", "int", 0, true},
283	{"ideal float", "{{typeOf 1.0}}", "float64", 0, true},
284	{"ideal exp float", "{{typeOf 1e1}}", "float64", 0, true},
285	{"ideal complex", "{{typeOf 1i}}", "complex128", 0, true},
286	{"ideal int", "{{typeOf " + bigInt + "}}", "int", 0, true},
287	{"ideal too big", "{{typeOf " + bigUint + "}}", "", 0, false},
288	{"ideal nil without type", "{{nil}}", "", 0, false},
289
290	// Fields of structs.
291	{".X", "-{{.X}}-", "-x-", tVal, true},
292	{".U.V", "-{{.U.V}}-", "-v-", tVal, true},
293	{".unexported", "{{.unexported}}", "", tVal, false},
294
295	// Fields on maps.
296	{"map .one", "{{.MSI.one}}", "1", tVal, true},
297	{"map .two", "{{.MSI.two}}", "2", tVal, true},
298	{"map .NO", "{{.MSI.NO}}", "", tVal, true}, // NOTE: <no value> in text/template
299	{"map .one interface", "{{.MXI.one}}", "1", tVal, true},
300	{"map .WRONG args", "{{.MSI.one 1}}", "", tVal, false},
301	{"map .WRONG type", "{{.MII.one}}", "", tVal, false},
302
303	// Dots of all kinds to test basic evaluation.
304	{"dot int", "<{{.}}>", "&lt;13>", 13, true},
305	{"dot uint", "<{{.}}>", "&lt;14>", uint(14), true},
306	{"dot float", "<{{.}}>", "&lt;15.1>", 15.1, true},
307	{"dot bool", "<{{.}}>", "&lt;true>", true, true},
308	{"dot complex", "<{{.}}>", "&lt;(16.2-17i)>", 16.2 - 17i, true},
309	{"dot string", "<{{.}}>", "&lt;hello>", "hello", true},
310	{"dot slice", "<{{.}}>", "&lt;[-1 -2 -3]>", []int{-1, -2, -3}, true},
311	{"dot map", "<{{.}}>", "&lt;map[two:22]>", map[string]int{"two": 22}, true},
312	{"dot struct", "<{{.}}>", "&lt;{7 seven}>", struct {
313		a int
314		b string
315	}{7, "seven"}, true},
316
317	// Variables.
318	{"$ int", "{{$}}", "123", 123, true},
319	{"$.I", "{{$.I}}", "17", tVal, true},
320	{"$.U.V", "{{$.U.V}}", "v", tVal, true},
321	{"declare in action", "{{$x := $.U.V}}{{$x}}", "v", tVal, true},
322	{"simple assignment", "{{$x := 2}}{{$x = 3}}{{$x}}", "3", tVal, true},
323	{"nested assignment",
324		"{{$x := 2}}{{if true}}{{$x = 3}}{{end}}{{$x}}",
325		"3", tVal, true},
326	{"nested assignment changes the last declaration",
327		"{{$x := 1}}{{if true}}{{$x := 2}}{{if true}}{{$x = 3}}{{end}}{{end}}{{$x}}",
328		"1", tVal, true},
329
330	// Type with String method.
331	{"V{6666}.String()", "-{{.V0}}-", "-{6666}-", tVal, true}, //  NOTE: -<6666>- in text/template
332	{"&V{7777}.String()", "-{{.V1}}-", "-&lt;7777&gt;-", tVal, true},
333	{"(*V)(nil).String()", "-{{.V2}}-", "-nilV-", tVal, true},
334
335	// Type with Error method.
336	{"W{888}.Error()", "-{{.W0}}-", "-{888}-", tVal, true}, // NOTE: -[888] in text/template
337	{"&W{999}.Error()", "-{{.W1}}-", "-[999]-", tVal, true},
338	{"(*W)(nil).Error()", "-{{.W2}}-", "-nilW-", tVal, true},
339
340	// Pointers.
341	{"*int", "{{.PI}}", "23", tVal, true},
342	{"*string", "{{.PS}}", "a string", tVal, true},
343	{"*[]int", "{{.PSI}}", "[21 22 23]", tVal, true},
344	{"*[]int[1]", "{{index .PSI 1}}", "22", tVal, true},
345	{"NIL", "{{.NIL}}", "&lt;nil&gt;", tVal, true},
346
347	// Empty interfaces holding values.
348	{"empty nil", "{{.Empty0}}", "", tVal, true}, // NOTE: <no value> in text/template
349	{"empty with int", "{{.Empty1}}", "3", tVal, true},
350	{"empty with string", "{{.Empty2}}", "empty2", tVal, true},
351	{"empty with slice", "{{.Empty3}}", "[7 8]", tVal, true},
352	{"empty with struct", "{{.Empty4}}", "{UinEmpty}", tVal, true},
353	{"empty with struct, field", "{{.Empty4.V}}", "UinEmpty", tVal, true},
354
355	// Edge cases with <no value> with an interface value
356	{"field on interface", "{{.foo}}", "", nil, true},                  // NOTE: <no value> in text/template
357	{"field on parenthesized interface", "{{(.).foo}}", "", nil, true}, // NOTE: <no value> in text/template
358
359	// Issue 31810: Parenthesized first element of pipeline with arguments.
360	// See also TestIssue31810.
361	{"unparenthesized non-function", "{{1 2}}", "", nil, false},
362	{"parenthesized non-function", "{{(1) 2}}", "", nil, false},
363	{"parenthesized non-function with no args", "{{(1)}}", "1", nil, true}, // This is fine.
364
365	// Method calls.
366	{".Method0", "-{{.Method0}}-", "-M0-", tVal, true},
367	{".Method1(1234)", "-{{.Method1 1234}}-", "-1234-", tVal, true},
368	{".Method1(.I)", "-{{.Method1 .I}}-", "-17-", tVal, true},
369	{".Method2(3, .X)", "-{{.Method2 3 .X}}-", "-Method2: 3 x-", tVal, true},
370	{".Method2(.U16, `str`)", "-{{.Method2 .U16 `str`}}-", "-Method2: 16 str-", tVal, true},
371	{".Method2(.U16, $x)", "{{if $x := .X}}-{{.Method2 .U16 $x}}{{end}}-", "-Method2: 16 x-", tVal, true},
372	{".Method3(nil constant)", "-{{.Method3 nil}}-", "-Method3: &lt;nil&gt;-", tVal, true},
373	{".Method3(nil value)", "-{{.Method3 .MXI.unset}}-", "-Method3: &lt;nil&gt;-", tVal, true},
374	{"method on var", "{{if $x := .}}-{{$x.Method2 .U16 $x.X}}{{end}}-", "-Method2: 16 x-", tVal, true},
375	{"method on chained var",
376		"{{range .MSIone}}{{if $.U.TrueFalse $.True}}{{$.U.TrueFalse $.True}}{{else}}WRONG{{end}}{{end}}",
377		"true", tVal, true},
378	{"chained method",
379		"{{range .MSIone}}{{if $.GetU.TrueFalse $.True}}{{$.U.TrueFalse $.True}}{{else}}WRONG{{end}}{{end}}",
380		"true", tVal, true},
381	{"chained method on variable",
382		"{{with $x := .}}{{with .SI}}{{$.GetU.TrueFalse $.True}}{{end}}{{end}}",
383		"true", tVal, true},
384	{".NilOKFunc not nil", "{{call .NilOKFunc .PI}}", "false", tVal, true},
385	{".NilOKFunc nil", "{{call .NilOKFunc nil}}", "true", tVal, true},
386	{"method on nil value from slice", "-{{range .}}{{.Method1 1234}}{{end}}-", "-1234-", tSliceOfNil, true},
387	{"method on typed nil interface value", "{{.NonEmptyInterfaceTypedNil.Method0}}", "M0", tVal, true},
388
389	// Function call builtin.
390	{".BinaryFunc", "{{call .BinaryFunc `1` `2`}}", "[1=2]", tVal, true},
391	{".VariadicFunc0", "{{call .VariadicFunc}}", "&lt;&gt;", tVal, true},
392	{".VariadicFunc2", "{{call .VariadicFunc `he` `llo`}}", "&lt;he&#43;llo&gt;", tVal, true},
393	{".VariadicFuncInt", "{{call .VariadicFuncInt 33 `he` `llo`}}", "33=&lt;he&#43;llo&gt;", tVal, true},
394	{"if .BinaryFunc call", "{{ if .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{end}}", "[1=2]", tVal, true},
395	{"if not .BinaryFunc call", "{{ if not .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{else}}No{{end}}", "No", tVal, true},
396	{"Interface Call", `{{stringer .S}}`, "foozle", map[string]any{"S": bytes.NewBufferString("foozle")}, true},
397	{".ErrFunc", "{{call .ErrFunc}}", "bla", tVal, true},
398	{"call nil", "{{call nil}}", "", tVal, false},
399
400	// Erroneous function calls (check args).
401	{".BinaryFuncTooFew", "{{call .BinaryFunc `1`}}", "", tVal, false},
402	{".BinaryFuncTooMany", "{{call .BinaryFunc `1` `2` `3`}}", "", tVal, false},
403	{".BinaryFuncBad0", "{{call .BinaryFunc 1 3}}", "", tVal, false},
404	{".BinaryFuncBad1", "{{call .BinaryFunc `1` 3}}", "", tVal, false},
405	{".VariadicFuncBad0", "{{call .VariadicFunc 3}}", "", tVal, false},
406	{".VariadicFuncIntBad0", "{{call .VariadicFuncInt}}", "", tVal, false},
407	{".VariadicFuncIntBad`", "{{call .VariadicFuncInt `x`}}", "", tVal, false},
408	{".VariadicFuncNilBad", "{{call .VariadicFunc nil}}", "", tVal, false},
409
410	// Pipelines.
411	{"pipeline", "-{{.Method0 | .Method2 .U16}}-", "-Method2: 16 M0-", tVal, true},
412	{"pipeline func", "-{{call .VariadicFunc `llo` | call .VariadicFunc `he` }}-", "-&lt;he&#43;&lt;llo&gt;&gt;-", tVal, true},
413
414	// Nil values aren't missing arguments.
415	{"nil pipeline", "{{ .Empty0 | call .NilOKFunc }}", "true", tVal, true},
416	{"nil call arg", "{{ call .NilOKFunc .Empty0 }}", "true", tVal, true},
417	{"bad nil pipeline", "{{ .Empty0 | .VariadicFunc }}", "", tVal, false},
418
419	// Parenthesized expressions
420	{"parens in pipeline", "{{printf `%d %d %d` (1) (2 | add 3) (add 4 (add 5 6))}}", "1 5 15", tVal, true},
421
422	// Parenthesized expressions with field accesses
423	{"parens: $ in paren", "{{($).X}}", "x", tVal, true},
424	{"parens: $.GetU in paren", "{{($.GetU).V}}", "v", tVal, true},
425	{"parens: $ in paren in pipe", "{{($ | echo).X}}", "x", tVal, true},
426	{"parens: spaces and args", `{{(makemap "up" "down" "left" "right").left}}`, "right", tVal, true},
427
428	// If.
429	{"if true", "{{if true}}TRUE{{end}}", "TRUE", tVal, true},
430	{"if false", "{{if false}}TRUE{{else}}FALSE{{end}}", "FALSE", tVal, true},
431	{"if nil", "{{if nil}}TRUE{{end}}", "", tVal, false},
432	{"if on typed nil interface value", "{{if .NonEmptyInterfaceTypedNil}}TRUE{{ end }}", "", tVal, true},
433	{"if 1", "{{if 1}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
434	{"if 0", "{{if 0}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
435	{"if 1.5", "{{if 1.5}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
436	{"if 0.0", "{{if .FloatZero}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
437	{"if 1.5i", "{{if 1.5i}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
438	{"if 0.0i", "{{if .ComplexZero}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
439	{"if emptystring", "{{if ``}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
440	{"if string", "{{if `notempty`}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
441	{"if emptyslice", "{{if .SIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
442	{"if slice", "{{if .SI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
443	{"if emptymap", "{{if .MSIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
444	{"if map", "{{if .MSI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
445	{"if map unset", "{{if .MXI.none}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
446	{"if map not unset", "{{if not .MXI.none}}ZERO{{else}}NON-ZERO{{end}}", "ZERO", tVal, true},
447	{"if $x with $y int", "{{if $x := true}}{{with $y := .I}}{{$x}},{{$y}}{{end}}{{end}}", "true,17", tVal, true},
448	{"if $x with $x int", "{{if $x := true}}{{with $x := .I}}{{$x}},{{end}}{{$x}}{{end}}", "17,true", tVal, true},
449	{"if else if", "{{if false}}FALSE{{else if true}}TRUE{{end}}", "TRUE", tVal, true},
450	{"if else chain", "{{if eq 1 3}}1{{else if eq 2 3}}2{{else if eq 3 3}}3{{end}}", "3", tVal, true},
451
452	// Print etc.
453	{"print", `{{print "hello, print"}}`, "hello, print", tVal, true},
454	{"print 123", `{{print 1 2 3}}`, "1 2 3", tVal, true},
455	{"print nil", `{{print nil}}`, "&lt;nil&gt;", tVal, true},
456	{"println", `{{println 1 2 3}}`, "1 2 3\n", tVal, true},
457	{"printf int", `{{printf "%04x" 127}}`, "007f", tVal, true},
458	{"printf float", `{{printf "%g" 3.5}}`, "3.5", tVal, true},
459	{"printf complex", `{{printf "%g" 1+7i}}`, "(1&#43;7i)", tVal, true},
460	{"printf string", `{{printf "%s" "hello"}}`, "hello", tVal, true},
461	{"printf function", `{{printf "%#q" zeroArgs}}`, "`zeroArgs`", tVal, true},
462	{"printf field", `{{printf "%s" .U.V}}`, "v", tVal, true},
463	{"printf method", `{{printf "%s" .Method0}}`, "M0", tVal, true},
464	{"printf dot", `{{with .I}}{{printf "%d" .}}{{end}}`, "17", tVal, true},
465	{"printf var", `{{with $x := .I}}{{printf "%d" $x}}{{end}}`, "17", tVal, true},
466	{"printf lots", `{{printf "%d %s %g %s" 127 "hello" 7-3i .Method0}}`, "127 hello (7-3i) M0", tVal, true},
467
468	// HTML.
469	{"html", `{{html "<script>alert(\"XSS\");</script>"}}`,
470		"&lt;script&gt;alert(&#34;XSS&#34;);&lt;/script&gt;", nil, true},
471	{"html pipeline", `{{printf "<script>alert(\"XSS\");</script>" | html}}`,
472		"&lt;script&gt;alert(&#34;XSS&#34;);&lt;/script&gt;", nil, true},
473	{"html", `{{html .PS}}`, "a string", tVal, true},
474	{"html typed nil", `{{html .NIL}}`, "&lt;nil&gt;", tVal, true},
475	{"html untyped nil", `{{html .Empty0}}`, "&lt;nil&gt;", tVal, true}, // NOTE: "&lt;no value&gt;" in text/template
476
477	// JavaScript.
478	{"js", `{{js .}}`, `It\&#39;d be nice.`, `It'd be nice.`, true},
479
480	// URL query.
481	{"urlquery", `{{"http://www.example.org/"|urlquery}}`, "http%3A%2F%2Fwww.example.org%2F", nil, true},
482
483	// Booleans
484	{"not", "{{not true}} {{not false}}", "false true", nil, true},
485	{"and", "{{and false 0}} {{and 1 0}} {{and 0 true}} {{and 1 1}}", "false 0 0 1", nil, true},
486	{"or", "{{or 0 0}} {{or 1 0}} {{or 0 true}} {{or 1 1}}", "0 1 true 1", nil, true},
487	{"boolean if", "{{if and true 1 `hi`}}TRUE{{else}}FALSE{{end}}", "TRUE", tVal, true},
488	{"boolean if not", "{{if and true 1 `hi` | not}}TRUE{{else}}FALSE{{end}}", "FALSE", nil, true},
489
490	// Indexing.
491	{"slice[0]", "{{index .SI 0}}", "3", tVal, true},
492	{"slice[1]", "{{index .SI 1}}", "4", tVal, true},
493	{"slice[HUGE]", "{{index .SI 10}}", "", tVal, false},
494	{"slice[WRONG]", "{{index .SI `hello`}}", "", tVal, false},
495	{"slice[nil]", "{{index .SI nil}}", "", tVal, false},
496	{"map[one]", "{{index .MSI `one`}}", "1", tVal, true},
497	{"map[two]", "{{index .MSI `two`}}", "2", tVal, true},
498	{"map[NO]", "{{index .MSI `XXX`}}", "0", tVal, true},
499	{"map[nil]", "{{index .MSI nil}}", "", tVal, false},
500	{"map[``]", "{{index .MSI ``}}", "0", tVal, true},
501	{"map[WRONG]", "{{index .MSI 10}}", "", tVal, false},
502	{"double index", "{{index .SMSI 1 `eleven`}}", "11", tVal, true},
503	{"nil[1]", "{{index nil 1}}", "", tVal, false},
504	{"map MI64S", "{{index .MI64S 2}}", "i642", tVal, true},
505	{"map MI32S", "{{index .MI32S 2}}", "two", tVal, true},
506	{"map MUI64S", "{{index .MUI64S 3}}", "ui643", tVal, true},
507	{"map MI8S", "{{index .MI8S 3}}", "i83", tVal, true},
508	{"map MUI8S", "{{index .MUI8S 2}}", "u82", tVal, true},
509	{"index of an interface field", "{{index .Empty3 0}}", "7", tVal, true},
510
511	// Slicing.
512	{"slice[:]", "{{slice .SI}}", "[3 4 5]", tVal, true},
513	{"slice[1:]", "{{slice .SI 1}}", "[4 5]", tVal, true},
514	{"slice[1:2]", "{{slice .SI 1 2}}", "[4]", tVal, true},
515	{"slice[-1:]", "{{slice .SI -1}}", "", tVal, false},
516	{"slice[1:-2]", "{{slice .SI 1 -2}}", "", tVal, false},
517	{"slice[1:2:-1]", "{{slice .SI 1 2 -1}}", "", tVal, false},
518	{"slice[2:1]", "{{slice .SI 2 1}}", "", tVal, false},
519	{"slice[2:2:1]", "{{slice .SI 2 2 1}}", "", tVal, false},
520	{"out of range", "{{slice .SI 4 5}}", "", tVal, false},
521	{"out of range", "{{slice .SI 2 2 5}}", "", tVal, false},
522	{"len(s) < indexes < cap(s)", "{{slice .SICap 6 10}}", "[0 0 0 0]", tVal, true},
523	{"len(s) < indexes < cap(s)", "{{slice .SICap 6 10 10}}", "[0 0 0 0]", tVal, true},
524	{"indexes > cap(s)", "{{slice .SICap 10 11}}", "", tVal, false},
525	{"indexes > cap(s)", "{{slice .SICap 6 10 11}}", "", tVal, false},
526	{"array[:]", "{{slice .AI}}", "[3 4 5]", tVal, true},
527	{"array[1:]", "{{slice .AI 1}}", "[4 5]", tVal, true},
528	{"array[1:2]", "{{slice .AI 1 2}}", "[4]", tVal, true},
529	{"string[:]", "{{slice .S}}", "xyz", tVal, true},
530	{"string[0:1]", "{{slice .S 0 1}}", "x", tVal, true},
531	{"string[1:]", "{{slice .S 1}}", "yz", tVal, true},
532	{"string[1:2]", "{{slice .S 1 2}}", "y", tVal, true},
533	{"out of range", "{{slice .S 1 5}}", "", tVal, false},
534	{"3-index slice of string", "{{slice .S 1 2 2}}", "", tVal, false},
535	{"slice of an interface field", "{{slice .Empty3 0 1}}", "[7]", tVal, true},
536
537	// Len.
538	{"slice", "{{len .SI}}", "3", tVal, true},
539	{"map", "{{len .MSI }}", "3", tVal, true},
540	{"len of int", "{{len 3}}", "", tVal, false},
541	{"len of nothing", "{{len .Empty0}}", "", tVal, false},
542	{"len of an interface field", "{{len .Empty3}}", "2", tVal, true},
543
544	// With.
545	{"with true", "{{with true}}{{.}}{{end}}", "true", tVal, true},
546	{"with false", "{{with false}}{{.}}{{else}}FALSE{{end}}", "FALSE", tVal, true},
547	{"with 1", "{{with 1}}{{.}}{{else}}ZERO{{end}}", "1", tVal, true},
548	{"with 0", "{{with 0}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
549	{"with 1.5", "{{with 1.5}}{{.}}{{else}}ZERO{{end}}", "1.5", tVal, true},
550	{"with 0.0", "{{with .FloatZero}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
551	{"with 1.5i", "{{with 1.5i}}{{.}}{{else}}ZERO{{end}}", "(0&#43;1.5i)", tVal, true},
552	{"with 0.0i", "{{with .ComplexZero}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
553	{"with emptystring", "{{with ``}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
554	{"with string", "{{with `notempty`}}{{.}}{{else}}EMPTY{{end}}", "notempty", tVal, true},
555	{"with emptyslice", "{{with .SIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
556	{"with slice", "{{with .SI}}{{.}}{{else}}EMPTY{{end}}", "[3 4 5]", tVal, true},
557	{"with emptymap", "{{with .MSIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
558	{"with map", "{{with .MSIone}}{{.}}{{else}}EMPTY{{end}}", "map[one:1]", tVal, true},
559	{"with empty interface, struct field", "{{with .Empty4}}{{.V}}{{end}}", "UinEmpty", tVal, true},
560	{"with $x int", "{{with $x := .I}}{{$x}}{{end}}", "17", tVal, true},
561	{"with $x struct.U.V", "{{with $x := $}}{{$x.U.V}}{{end}}", "v", tVal, true},
562	{"with variable and action", "{{with $x := $}}{{$y := $.U.V}}{{$y}}{{end}}", "v", tVal, true},
563	{"with on typed nil interface value", "{{with .NonEmptyInterfaceTypedNil}}TRUE{{ end }}", "", tVal, true},
564	{"with else with", "{{with 0}}{{.}}{{else with true}}{{.}}{{end}}", "true", tVal, true},
565	{"with else with chain", "{{with 0}}{{.}}{{else with false}}{{.}}{{else with `notempty`}}{{.}}{{end}}", "notempty", tVal, true},
566
567	// Range.
568	{"range []int", "{{range .SI}}-{{.}}-{{end}}", "-3--4--5-", tVal, true},
569	{"range empty no else", "{{range .SIEmpty}}-{{.}}-{{end}}", "", tVal, true},
570	{"range []int else", "{{range .SI}}-{{.}}-{{else}}EMPTY{{end}}", "-3--4--5-", tVal, true},
571	{"range empty else", "{{range .SIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
572	{"range []int break else", "{{range .SI}}-{{.}}-{{break}}NOTREACHED{{else}}EMPTY{{end}}", "-3-", tVal, true},
573	{"range []int continue else", "{{range .SI}}-{{.}}-{{continue}}NOTREACHED{{else}}EMPTY{{end}}", "-3--4--5-", tVal, true},
574	{"range []bool", "{{range .SB}}-{{.}}-{{end}}", "-true--false-", tVal, true},
575	{"range []int method", "{{range .SI | .MAdd .I}}-{{.}}-{{end}}", "-20--21--22-", tVal, true},
576	{"range map", "{{range .MSI}}-{{.}}-{{end}}", "-1--3--2-", tVal, true},
577	{"range empty map no else", "{{range .MSIEmpty}}-{{.}}-{{end}}", "", tVal, true},
578	{"range map else", "{{range .MSI}}-{{.}}-{{else}}EMPTY{{end}}", "-1--3--2-", tVal, true},
579	{"range empty map else", "{{range .MSIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
580	{"range empty interface", "{{range .Empty3}}-{{.}}-{{else}}EMPTY{{end}}", "-7--8-", tVal, true},
581	{"range empty nil", "{{range .Empty0}}-{{.}}-{{end}}", "", tVal, true},
582	{"range $x SI", "{{range $x := .SI}}<{{$x}}>{{end}}", "&lt;3>&lt;4>&lt;5>", tVal, true},
583	{"range $x $y SI", "{{range $x, $y := .SI}}<{{$x}}={{$y}}>{{end}}", "&lt;0=3>&lt;1=4>&lt;2=5>", tVal, true},
584	{"range $x MSIone", "{{range $x := .MSIone}}<{{$x}}>{{end}}", "&lt;1>", tVal, true},
585	{"range $x $y MSIone", "{{range $x, $y := .MSIone}}<{{$x}}={{$y}}>{{end}}", "&lt;one=1>", tVal, true},
586	{"range $x PSI", "{{range $x := .PSI}}<{{$x}}>{{end}}", "&lt;21>&lt;22>&lt;23>", tVal, true},
587	{"declare in range", "{{range $x := .PSI}}<{{$foo:=$x}}{{$x}}>{{end}}", "&lt;21>&lt;22>&lt;23>", tVal, true},
588	{"range count", `{{range $i, $x := count 5}}[{{$i}}]{{$x}}{{end}}`, "[0]a[1]b[2]c[3]d[4]e", tVal, true},
589	{"range nil count", `{{range $i, $x := count 0}}{{else}}empty{{end}}`, "empty", tVal, true},
590
591	// Cute examples.
592	{"or as if true", `{{or .SI "slice is empty"}}`, "[3 4 5]", tVal, true},
593	{"or as if false", `{{or .SIEmpty "slice is empty"}}`, "slice is empty", tVal, true},
594
595	// Error handling.
596	{"error method, error", "{{.MyError true}}", "", tVal, false},
597	{"error method, no error", "{{.MyError false}}", "false", tVal, true},
598
599	// Numbers
600	{"decimal", "{{print 1234}}", "1234", tVal, true},
601	{"decimal _", "{{print 12_34}}", "1234", tVal, true},
602	{"binary", "{{print 0b101}}", "5", tVal, true},
603	{"binary _", "{{print 0b_1_0_1}}", "5", tVal, true},
604	{"BINARY", "{{print 0B101}}", "5", tVal, true},
605	{"octal0", "{{print 0377}}", "255", tVal, true},
606	{"octal", "{{print 0o377}}", "255", tVal, true},
607	{"octal _", "{{print 0o_3_7_7}}", "255", tVal, true},
608	{"OCTAL", "{{print 0O377}}", "255", tVal, true},
609	{"hex", "{{print 0x123}}", "291", tVal, true},
610	{"hex _", "{{print 0x1_23}}", "291", tVal, true},
611	{"HEX", "{{print 0X123ABC}}", "1194684", tVal, true},
612	{"float", "{{print 123.4}}", "123.4", tVal, true},
613	{"float _", "{{print 0_0_1_2_3.4}}", "123.4", tVal, true},
614	{"hex float", "{{print +0x1.ep+2}}", "7.5", tVal, true},
615	{"hex float _", "{{print +0x_1.e_0p+0_2}}", "7.5", tVal, true},
616	{"HEX float", "{{print +0X1.EP+2}}", "7.5", tVal, true},
617	{"print multi", "{{print 1_2_3_4 7.5_00_00_00}}", "1234 7.5", tVal, true},
618	{"print multi2", "{{print 1234 0x0_1.e_0p+02}}", "1234 7.5", tVal, true},
619
620	// Fixed bugs.
621	// Must separate dot and receiver; otherwise args are evaluated with dot set to variable.
622	{"bug0", "{{range .MSIone}}{{if $.Method1 .}}X{{end}}{{end}}", "X", tVal, true},
623	// Do not loop endlessly in indirect for non-empty interfaces.
624	// The bug appears with *interface only; looped forever.
625	{"bug1", "{{.Method0}}", "M0", &iVal, true},
626	// Was taking address of interface field, so method set was empty.
627	{"bug2", "{{$.NonEmptyInterface.Method0}}", "M0", tVal, true},
628	// Struct values were not legal in with - mere oversight.
629	{"bug3", "{{with $}}{{.Method0}}{{end}}", "M0", tVal, true},
630	// Nil interface values in if.
631	{"bug4", "{{if .Empty0}}non-nil{{else}}nil{{end}}", "nil", tVal, true},
632	// Stringer.
633	{"bug5", "{{.Str}}", "foozle", tVal, true},
634	{"bug5a", "{{.Err}}", "erroozle", tVal, true},
635	// Args need to be indirected and dereferenced sometimes.
636	{"bug6a", "{{vfunc .V0 .V1}}", "vfunc", tVal, true},
637	{"bug6b", "{{vfunc .V0 .V0}}", "vfunc", tVal, true},
638	{"bug6c", "{{vfunc .V1 .V0}}", "vfunc", tVal, true},
639	{"bug6d", "{{vfunc .V1 .V1}}", "vfunc", tVal, true},
640	// Legal parse but illegal execution: non-function should have no arguments.
641	{"bug7a", "{{3 2}}", "", tVal, false},
642	{"bug7b", "{{$x := 1}}{{$x 2}}", "", tVal, false},
643	{"bug7c", "{{$x := 1}}{{3 | $x}}", "", tVal, false},
644	// Pipelined arg was not being type-checked.
645	{"bug8a", "{{3|oneArg}}", "", tVal, false},
646	{"bug8b", "{{4|dddArg 3}}", "", tVal, false},
647	// A bug was introduced that broke map lookups for lower-case names.
648	{"bug9", "{{.cause}}", "neglect", map[string]string{"cause": "neglect"}, true},
649	// Field chain starting with function did not work.
650	{"bug10", "{{mapOfThree.three}}-{{(mapOfThree).three}}", "3-3", 0, true},
651	// Dereferencing nil pointer while evaluating function arguments should not panic. Issue 7333.
652	{"bug11", "{{valueString .PS}}", "", T{}, false},
653	// 0xef gave constant type float64. Issue 8622.
654	{"bug12xe", "{{printf `%T` 0xef}}", "int", T{}, true},
655	{"bug12xE", "{{printf `%T` 0xEE}}", "int", T{}, true},
656	{"bug12Xe", "{{printf `%T` 0Xef}}", "int", T{}, true},
657	{"bug12XE", "{{printf `%T` 0XEE}}", "int", T{}, true},
658	// Chained nodes did not work as arguments. Issue 8473.
659	{"bug13", "{{print (.Copy).I}}", "17", tVal, true},
660	// Didn't protect against nil or literal values in field chains.
661	{"bug14a", "{{(nil).True}}", "", tVal, false},
662	{"bug14b", "{{$x := nil}}{{$x.anything}}", "", tVal, false},
663	{"bug14c", `{{$x := (1.0)}}{{$y := ("hello")}}{{$x.anything}}{{$y.true}}`, "", tVal, false},
664	// Didn't call validateType on function results. Issue 10800.
665	{"bug15", "{{valueString returnInt}}", "", tVal, false},
666	// Variadic function corner cases. Issue 10946.
667	{"bug16a", "{{true|printf}}", "", tVal, false},
668	{"bug16b", "{{1|printf}}", "", tVal, false},
669	{"bug16c", "{{1.1|printf}}", "", tVal, false},
670	{"bug16d", "{{'x'|printf}}", "", tVal, false},
671	{"bug16e", "{{0i|printf}}", "", tVal, false},
672	{"bug16f", "{{true|twoArgs \"xxx\"}}", "", tVal, false},
673	{"bug16g", "{{\"aaa\" |twoArgs \"bbb\"}}", "twoArgs=bbbaaa", tVal, true},
674	{"bug16h", "{{1|oneArg}}", "", tVal, false},
675	{"bug16i", "{{\"aaa\"|oneArg}}", "oneArg=aaa", tVal, true},
676	{"bug16j", "{{1+2i|printf \"%v\"}}", "(1&#43;2i)", tVal, true},
677	{"bug16k", "{{\"aaa\"|printf }}", "aaa", tVal, true},
678	{"bug17a", "{{.NonEmptyInterface.X}}", "x", tVal, true},
679	{"bug17b", "-{{.NonEmptyInterface.Method1 1234}}-", "-1234-", tVal, true},
680	{"bug17c", "{{len .NonEmptyInterfacePtS}}", "2", tVal, true},
681	{"bug17d", "{{index .NonEmptyInterfacePtS 0}}", "a", tVal, true},
682	{"bug17e", "{{range .NonEmptyInterfacePtS}}-{{.}}-{{end}}", "-a--b-", tVal, true},
683
684	// More variadic function corner cases. Some runes would get evaluated
685	// as constant floats instead of ints. Issue 34483.
686	{"bug18a", "{{eq . '.'}}", "true", '.', true},
687	{"bug18b", "{{eq . 'e'}}", "true", 'e', true},
688	{"bug18c", "{{eq . 'P'}}", "true", 'P', true},
689}
690
691func zeroArgs() string {
692	return "zeroArgs"
693}
694
695func oneArg(a string) string {
696	return "oneArg=" + a
697}
698
699func twoArgs(a, b string) string {
700	return "twoArgs=" + a + b
701}
702
703func dddArg(a int, b ...string) string {
704	return fmt.Sprintln(a, b)
705}
706
707// count returns a channel that will deliver n sequential 1-letter strings starting at "a"
708func count(n int) chan string {
709	if n == 0 {
710		return nil
711	}
712	c := make(chan string)
713	go func() {
714		for i := 0; i < n; i++ {
715			c <- "abcdefghijklmnop"[i : i+1]
716		}
717		close(c)
718	}()
719	return c
720}
721
722// vfunc takes a *V and a V
723func vfunc(V, *V) string {
724	return "vfunc"
725}
726
727// valueString takes a string, not a pointer.
728func valueString(v string) string {
729	return "value is ignored"
730}
731
732// returnInt returns an int
733func returnInt() int {
734	return 7
735}
736
737func add(args ...int) int {
738	sum := 0
739	for _, x := range args {
740		sum += x
741	}
742	return sum
743}
744
745func echo(arg any) any {
746	return arg
747}
748
749func makemap(arg ...string) map[string]string {
750	if len(arg)%2 != 0 {
751		panic("bad makemap")
752	}
753	m := make(map[string]string)
754	for i := 0; i < len(arg); i += 2 {
755		m[arg[i]] = arg[i+1]
756	}
757	return m
758}
759
760func stringer(s fmt.Stringer) string {
761	return s.String()
762}
763
764func mapOfThree() any {
765	return map[string]int{"three": 3}
766}
767
768func testExecute(execTests []execTest, template *Template, t *testing.T) {
769	b := new(strings.Builder)
770	funcs := FuncMap{
771		"add":         add,
772		"count":       count,
773		"dddArg":      dddArg,
774		"echo":        echo,
775		"makemap":     makemap,
776		"mapOfThree":  mapOfThree,
777		"oneArg":      oneArg,
778		"returnInt":   returnInt,
779		"stringer":    stringer,
780		"twoArgs":     twoArgs,
781		"typeOf":      typeOf,
782		"valueString": valueString,
783		"vfunc":       vfunc,
784		"zeroArgs":    zeroArgs,
785	}
786	for _, test := range execTests {
787		var tmpl *Template
788		var err error
789		if template == nil {
790			tmpl, err = New(test.name).Funcs(funcs).Parse(test.input)
791		} else {
792			tmpl, err = template.Clone()
793			if err != nil {
794				t.Errorf("%s: clone error: %s", test.name, err)
795				continue
796			}
797			tmpl, err = tmpl.New(test.name).Funcs(funcs).Parse(test.input)
798		}
799		if err != nil {
800			t.Errorf("%s: parse error: %s", test.name, err)
801			continue
802		}
803		b.Reset()
804		err = tmpl.Execute(b, test.data)
805		switch {
806		case !test.ok && err == nil:
807			t.Errorf("%s: expected error; got none", test.name)
808			continue
809		case test.ok && err != nil:
810			t.Errorf("%s: unexpected execute error: %s", test.name, err)
811			continue
812		case !test.ok && err != nil:
813			// expected error, got one
814			if *debug {
815				fmt.Printf("%s: %s\n\t%s\n", test.name, test.input, err)
816			}
817		}
818		result := b.String()
819		if result != test.output {
820			t.Errorf("%s: expected\n\t%q\ngot\n\t%q", test.name, test.output, result)
821		}
822	}
823}
824
825func TestExecute(t *testing.T) {
826	testExecute(execTests, nil, t)
827}
828
829var delimPairs = []string{
830	"", "", // default
831	"{{", "}}", // same as default
832	"|", "|", // same
833	"(日)", "(本)", // peculiar
834}
835
836func TestDelims(t *testing.T) {
837	const hello = "Hello, world"
838	var value = struct{ Str string }{hello}
839	for i := 0; i < len(delimPairs); i += 2 {
840		text := ".Str"
841		left := delimPairs[i+0]
842		trueLeft := left
843		right := delimPairs[i+1]
844		trueRight := right
845		if left == "" { // default case
846			trueLeft = "{{"
847		}
848		if right == "" { // default case
849			trueRight = "}}"
850		}
851		text = trueLeft + text + trueRight
852		// Now add a comment
853		text += trueLeft + "/*comment*/" + trueRight
854		// Now add  an action containing a string.
855		text += trueLeft + `"` + trueLeft + `"` + trueRight
856		// At this point text looks like `{{.Str}}{{/*comment*/}}{{"{{"}}`.
857		tmpl, err := New("delims").Delims(left, right).Parse(text)
858		if err != nil {
859			t.Fatalf("delim %q text %q parse err %s", left, text, err)
860		}
861		var b = new(strings.Builder)
862		err = tmpl.Execute(b, value)
863		if err != nil {
864			t.Fatalf("delim %q exec err %s", left, err)
865		}
866		if b.String() != hello+trueLeft {
867			t.Errorf("expected %q got %q", hello+trueLeft, b.String())
868		}
869	}
870}
871
872// Check that an error from a method flows back to the top.
873func TestExecuteError(t *testing.T) {
874	b := new(bytes.Buffer)
875	tmpl := New("error")
876	_, err := tmpl.Parse("{{.MyError true}}")
877	if err != nil {
878		t.Fatalf("parse error: %s", err)
879	}
880	err = tmpl.Execute(b, tVal)
881	if err == nil {
882		t.Errorf("expected error; got none")
883	} else if !strings.Contains(err.Error(), myError.Error()) {
884		if *debug {
885			fmt.Printf("test execute error: %s\n", err)
886		}
887		t.Errorf("expected myError; got %s", err)
888	}
889}
890
891const execErrorText = `line 1
892line 2
893line 3
894{{template "one" .}}
895{{define "one"}}{{template "two" .}}{{end}}
896{{define "two"}}{{template "three" .}}{{end}}
897{{define "three"}}{{index "hi" $}}{{end}}`
898
899// Check that an error from a nested template contains all the relevant information.
900func TestExecError(t *testing.T) {
901	tmpl, err := New("top").Parse(execErrorText)
902	if err != nil {
903		t.Fatal("parse error:", err)
904	}
905	var b bytes.Buffer
906	err = tmpl.Execute(&b, 5) // 5 is out of range indexing "hi"
907	if err == nil {
908		t.Fatal("expected error")
909	}
910	const want = `template: top:7:20: executing "three" at <index "hi" $>: error calling index: index out of range: 5`
911	got := err.Error()
912	if got != want {
913		t.Errorf("expected\n%q\ngot\n%q", want, got)
914	}
915}
916
917func TestJSEscaping(t *testing.T) {
918	testCases := []struct {
919		in, exp string
920	}{
921		{`a`, `a`},
922		{`'foo`, `\'foo`},
923		{`Go "jump" \`, `Go \"jump\" \\`},
924		{`Yukihiro says "今日は世界"`, `Yukihiro says \"今日は世界\"`},
925		{"unprintable \uFFFE", `unprintable \uFFFE`},
926		{`<html>`, `\u003Chtml\u003E`},
927		{`no = in attributes`, `no \u003D in attributes`},
928		{`&#x27; does not become HTML entity`, `\u0026#x27; does not become HTML entity`},
929	}
930	for _, tc := range testCases {
931		s := JSEscapeString(tc.in)
932		if s != tc.exp {
933			t.Errorf("JS escaping [%s] got [%s] want [%s]", tc.in, s, tc.exp)
934		}
935	}
936}
937
938// A nice example: walk a binary tree.
939
940type Tree struct {
941	Val         int
942	Left, Right *Tree
943}
944
945// Use different delimiters to test Set.Delims.
946// Also test the trimming of leading and trailing spaces.
947const treeTemplate = `
948	(- define "tree" -)
949	[
950		(- .Val -)
951		(- with .Left -)
952			(template "tree" . -)
953		(- end -)
954		(- with .Right -)
955			(- template "tree" . -)
956		(- end -)
957	]
958	(- end -)
959`
960
961func TestTree(t *testing.T) {
962	var tree = &Tree{
963		1,
964		&Tree{
965			2, &Tree{
966				3,
967				&Tree{
968					4, nil, nil,
969				},
970				nil,
971			},
972			&Tree{
973				5,
974				&Tree{
975					6, nil, nil,
976				},
977				nil,
978			},
979		},
980		&Tree{
981			7,
982			&Tree{
983				8,
984				&Tree{
985					9, nil, nil,
986				},
987				nil,
988			},
989			&Tree{
990				10,
991				&Tree{
992					11, nil, nil,
993				},
994				nil,
995			},
996		},
997	}
998	tmpl, err := New("root").Delims("(", ")").Parse(treeTemplate)
999	if err != nil {
1000		t.Fatal("parse error:", err)
1001	}
1002	var b strings.Builder
1003	const expect = "[1[2[3[4]][5[6]]][7[8[9]][10[11]]]]"
1004	// First by looking up the template.
1005	err = tmpl.Lookup("tree").Execute(&b, tree)
1006	if err != nil {
1007		t.Fatal("exec error:", err)
1008	}
1009	result := b.String()
1010	if result != expect {
1011		t.Errorf("expected %q got %q", expect, result)
1012	}
1013	// Then direct to execution.
1014	b.Reset()
1015	err = tmpl.ExecuteTemplate(&b, "tree", tree)
1016	if err != nil {
1017		t.Fatal("exec error:", err)
1018	}
1019	result = b.String()
1020	if result != expect {
1021		t.Errorf("expected %q got %q", expect, result)
1022	}
1023}
1024
1025func TestExecuteOnNewTemplate(t *testing.T) {
1026	// This is issue 3872.
1027	New("Name").Templates()
1028	// This is issue 11379.
1029	// new(Template).Templates() // TODO: crashes
1030	// new(Template).Parse("") // TODO: crashes
1031	// new(Template).New("abc").Parse("") // TODO: crashes
1032	// new(Template).Execute(nil, nil)                // TODO: crashes; returns an error (but does not crash)
1033	// new(Template).ExecuteTemplate(nil, "XXX", nil) // TODO: crashes; returns an error (but does not crash)
1034}
1035
1036const testTemplates = `{{define "one"}}one{{end}}{{define "two"}}two{{end}}`
1037
1038func TestMessageForExecuteEmpty(t *testing.T) {
1039	// Test a truly empty template.
1040	tmpl := New("empty")
1041	var b bytes.Buffer
1042	err := tmpl.Execute(&b, 0)
1043	if err == nil {
1044		t.Fatal("expected initial error")
1045	}
1046	got := err.Error()
1047	want := `template: "empty" is an incomplete or empty template` // NOTE: text/template has extra "empty: " in message
1048	if got != want {
1049		t.Errorf("expected error %s got %s", want, got)
1050	}
1051
1052	// Add a non-empty template to check that the error is helpful.
1053	tmpl = New("empty")
1054	tests, err := New("").Parse(testTemplates)
1055	if err != nil {
1056		t.Fatal(err)
1057	}
1058	tmpl.AddParseTree("secondary", tests.Tree)
1059	err = tmpl.Execute(&b, 0)
1060	if err == nil {
1061		t.Fatal("expected second error")
1062	}
1063	got = err.Error()
1064	if got != want {
1065		t.Errorf("expected error %s got %s", want, got)
1066	}
1067	// Make sure we can execute the secondary.
1068	err = tmpl.ExecuteTemplate(&b, "secondary", 0)
1069	if err != nil {
1070		t.Fatal(err)
1071	}
1072}
1073
1074func TestFinalForPrintf(t *testing.T) {
1075	tmpl, err := New("").Parse(`{{"x" | printf}}`)
1076	if err != nil {
1077		t.Fatal(err)
1078	}
1079	var b bytes.Buffer
1080	err = tmpl.Execute(&b, 0)
1081	if err != nil {
1082		t.Fatal(err)
1083	}
1084}
1085
1086type cmpTest struct {
1087	expr  string
1088	truth string
1089	ok    bool
1090}
1091
1092var cmpTests = []cmpTest{
1093	{"eq true true", "true", true},
1094	{"eq true false", "false", true},
1095	{"eq 1+2i 1+2i", "true", true},
1096	{"eq 1+2i 1+3i", "false", true},
1097	{"eq 1.5 1.5", "true", true},
1098	{"eq 1.5 2.5", "false", true},
1099	{"eq 1 1", "true", true},
1100	{"eq 1 2", "false", true},
1101	{"eq `xy` `xy`", "true", true},
1102	{"eq `xy` `xyz`", "false", true},
1103	{"eq .Uthree .Uthree", "true", true},
1104	{"eq .Uthree .Ufour", "false", true},
1105	{"eq 3 4 5 6 3", "true", true},
1106	{"eq 3 4 5 6 7", "false", true},
1107	{"ne true true", "false", true},
1108	{"ne true false", "true", true},
1109	{"ne 1+2i 1+2i", "false", true},
1110	{"ne 1+2i 1+3i", "true", true},
1111	{"ne 1.5 1.5", "false", true},
1112	{"ne 1.5 2.5", "true", true},
1113	{"ne 1 1", "false", true},
1114	{"ne 1 2", "true", true},
1115	{"ne `xy` `xy`", "false", true},
1116	{"ne `xy` `xyz`", "true", true},
1117	{"ne .Uthree .Uthree", "false", true},
1118	{"ne .Uthree .Ufour", "true", true},
1119	{"lt 1.5 1.5", "false", true},
1120	{"lt 1.5 2.5", "true", true},
1121	{"lt 1 1", "false", true},
1122	{"lt 1 2", "true", true},
1123	{"lt `xy` `xy`", "false", true},
1124	{"lt `xy` `xyz`", "true", true},
1125	{"lt .Uthree .Uthree", "false", true},
1126	{"lt .Uthree .Ufour", "true", true},
1127	{"le 1.5 1.5", "true", true},
1128	{"le 1.5 2.5", "true", true},
1129	{"le 2.5 1.5", "false", true},
1130	{"le 1 1", "true", true},
1131	{"le 1 2", "true", true},
1132	{"le 2 1", "false", true},
1133	{"le `xy` `xy`", "true", true},
1134	{"le `xy` `xyz`", "true", true},
1135	{"le `xyz` `xy`", "false", true},
1136	{"le .Uthree .Uthree", "true", true},
1137	{"le .Uthree .Ufour", "true", true},
1138	{"le .Ufour .Uthree", "false", true},
1139	{"gt 1.5 1.5", "false", true},
1140	{"gt 1.5 2.5", "false", true},
1141	{"gt 1 1", "false", true},
1142	{"gt 2 1", "true", true},
1143	{"gt 1 2", "false", true},
1144	{"gt `xy` `xy`", "false", true},
1145	{"gt `xy` `xyz`", "false", true},
1146	{"gt .Uthree .Uthree", "false", true},
1147	{"gt .Uthree .Ufour", "false", true},
1148	{"gt .Ufour .Uthree", "true", true},
1149	{"ge 1.5 1.5", "true", true},
1150	{"ge 1.5 2.5", "false", true},
1151	{"ge 2.5 1.5", "true", true},
1152	{"ge 1 1", "true", true},
1153	{"ge 1 2", "false", true},
1154	{"ge 2 1", "true", true},
1155	{"ge `xy` `xy`", "true", true},
1156	{"ge `xy` `xyz`", "false", true},
1157	{"ge `xyz` `xy`", "true", true},
1158	{"ge .Uthree .Uthree", "true", true},
1159	{"ge .Uthree .Ufour", "false", true},
1160	{"ge .Ufour .Uthree", "true", true},
1161	// Mixing signed and unsigned integers.
1162	{"eq .Uthree .Three", "true", true},
1163	{"eq .Three .Uthree", "true", true},
1164	{"le .Uthree .Three", "true", true},
1165	{"le .Three .Uthree", "true", true},
1166	{"ge .Uthree .Three", "true", true},
1167	{"ge .Three .Uthree", "true", true},
1168	{"lt .Uthree .Three", "false", true},
1169	{"lt .Three .Uthree", "false", true},
1170	{"gt .Uthree .Three", "false", true},
1171	{"gt .Three .Uthree", "false", true},
1172	{"eq .Ufour .Three", "false", true},
1173	{"lt .Ufour .Three", "false", true},
1174	{"gt .Ufour .Three", "true", true},
1175	{"eq .NegOne .Uthree", "false", true},
1176	{"eq .Uthree .NegOne", "false", true},
1177	{"ne .NegOne .Uthree", "true", true},
1178	{"ne .Uthree .NegOne", "true", true},
1179	{"lt .NegOne .Uthree", "true", true},
1180	{"lt .Uthree .NegOne", "false", true},
1181	{"le .NegOne .Uthree", "true", true},
1182	{"le .Uthree .NegOne", "false", true},
1183	{"gt .NegOne .Uthree", "false", true},
1184	{"gt .Uthree .NegOne", "true", true},
1185	{"ge .NegOne .Uthree", "false", true},
1186	{"ge .Uthree .NegOne", "true", true},
1187	{"eq (index `x` 0) 'x'", "true", true}, // The example that triggered this rule.
1188	{"eq (index `x` 0) 'y'", "false", true},
1189	{"eq .V1 .V2", "true", true},
1190	{"eq .Ptr .Ptr", "true", true},
1191	{"eq .Ptr .NilPtr", "false", true},
1192	{"eq .NilPtr .NilPtr", "true", true},
1193	{"eq .Iface1 .Iface1", "true", true},
1194	{"eq .Iface1 .Iface2", "false", true},
1195	{"eq .Iface2 .Iface2", "true", true},
1196	{"eq .Map .Map", "true", true},        // Uncomparable types but nil is OK.
1197	{"eq .Map nil", "true", true},         // Uncomparable types but nil is OK.
1198	{"eq nil .Map", "true", true},         // Uncomparable types but nil is OK.
1199	{"eq .Map .NonNilMap", "false", true}, // Uncomparable types but nil is OK.
1200	// Errors
1201	{"eq `xy` 1", "", false},                // Different types.
1202	{"eq 2 2.0", "", false},                 // Different types.
1203	{"lt true true", "", false},             // Unordered types.
1204	{"lt 1+0i 1+0i", "", false},             // Unordered types.
1205	{"eq .Ptr 1", "", false},                // Incompatible types.
1206	{"eq .Ptr .NegOne", "", false},          // Incompatible types.
1207	{"eq .Map .V1", "", false},              // Uncomparable types.
1208	{"eq .NonNilMap .NonNilMap", "", false}, // Uncomparable types.
1209}
1210
1211func TestComparison(t *testing.T) {
1212	b := new(strings.Builder)
1213	var cmpStruct = struct {
1214		Uthree, Ufour  uint
1215		NegOne, Three  int
1216		Ptr, NilPtr    *int
1217		NonNilMap      map[int]int
1218		Map            map[int]int
1219		V1, V2         V
1220		Iface1, Iface2 fmt.Stringer
1221	}{
1222		Uthree:    3,
1223		Ufour:     4,
1224		NegOne:    -1,
1225		Three:     3,
1226		Ptr:       new(int),
1227		NonNilMap: make(map[int]int),
1228		Iface1:    b,
1229	}
1230	for _, test := range cmpTests {
1231		text := fmt.Sprintf("{{if %s}}true{{else}}false{{end}}", test.expr)
1232		tmpl, err := New("empty").Parse(text)
1233		if err != nil {
1234			t.Fatalf("%q: %s", test.expr, err)
1235		}
1236		b.Reset()
1237		err = tmpl.Execute(b, &cmpStruct)
1238		if test.ok && err != nil {
1239			t.Errorf("%s errored incorrectly: %s", test.expr, err)
1240			continue
1241		}
1242		if !test.ok && err == nil {
1243			t.Errorf("%s did not error", test.expr)
1244			continue
1245		}
1246		if b.String() != test.truth {
1247			t.Errorf("%s: want %s; got %s", test.expr, test.truth, b.String())
1248		}
1249	}
1250}
1251
1252func TestMissingMapKey(t *testing.T) {
1253	data := map[string]int{
1254		"x": 99,
1255	}
1256	tmpl, err := New("t1").Parse("{{.x}} {{.y}}")
1257	if err != nil {
1258		t.Fatal(err)
1259	}
1260	var b strings.Builder
1261	// By default, just get "<no value>" // NOTE: not in html/template, get empty string
1262	err = tmpl.Execute(&b, data)
1263	if err != nil {
1264		t.Fatal(err)
1265	}
1266	want := "99 "
1267	got := b.String()
1268	if got != want {
1269		t.Errorf("got %q; expected %q", got, want)
1270	}
1271	// Same if we set the option explicitly to the default.
1272	tmpl.Option("missingkey=default")
1273	b.Reset()
1274	err = tmpl.Execute(&b, data)
1275	if err != nil {
1276		t.Fatal("default:", err)
1277	}
1278	got = b.String()
1279	if got != want {
1280		t.Errorf("got %q; expected %q", got, want)
1281	}
1282	// Next we ask for a zero value
1283	tmpl.Option("missingkey=zero")
1284	b.Reset()
1285	err = tmpl.Execute(&b, data)
1286	if err != nil {
1287		t.Fatal("zero:", err)
1288	}
1289	want = "99 0"
1290	got = b.String()
1291	if got != want {
1292		t.Errorf("got %q; expected %q", got, want)
1293	}
1294	// Now we ask for an error.
1295	tmpl.Option("missingkey=error")
1296	err = tmpl.Execute(&b, data)
1297	if err == nil {
1298		t.Errorf("expected error; got none")
1299	}
1300	// same Option, but now a nil interface: ask for an error
1301	err = tmpl.Execute(&b, nil)
1302	t.Log(err)
1303	if err == nil {
1304		t.Errorf("expected error for nil-interface; got none")
1305	}
1306}
1307
1308// Test that the error message for multiline unterminated string
1309// refers to the line number of the opening quote.
1310func TestUnterminatedStringError(t *testing.T) {
1311	_, err := New("X").Parse("hello\n\n{{`unterminated\n\n\n\n}}\n some more\n\n")
1312	if err == nil {
1313		t.Fatal("expected error")
1314	}
1315	str := err.Error()
1316	if !strings.Contains(str, "X:3: unterminated raw quoted string") {
1317		t.Fatalf("unexpected error: %s", str)
1318	}
1319}
1320
1321const alwaysErrorText = "always be failing"
1322
1323var alwaysError = errors.New(alwaysErrorText)
1324
1325type ErrorWriter int
1326
1327func (e ErrorWriter) Write(p []byte) (int, error) {
1328	return 0, alwaysError
1329}
1330
1331func TestExecuteGivesExecError(t *testing.T) {
1332	// First, a non-execution error shouldn't be an ExecError.
1333	tmpl, err := New("X").Parse("hello")
1334	if err != nil {
1335		t.Fatal(err)
1336	}
1337	err = tmpl.Execute(ErrorWriter(0), 0)
1338	if err == nil {
1339		t.Fatal("expected error; got none")
1340	}
1341	if err.Error() != alwaysErrorText {
1342		t.Errorf("expected %q error; got %q", alwaysErrorText, err)
1343	}
1344	// This one should be an ExecError.
1345	tmpl, err = New("X").Parse("hello, {{.X.Y}}")
1346	if err != nil {
1347		t.Fatal(err)
1348	}
1349	err = tmpl.Execute(io.Discard, 0)
1350	if err == nil {
1351		t.Fatal("expected error; got none")
1352	}
1353	eerr, ok := err.(template.ExecError)
1354	if !ok {
1355		t.Fatalf("did not expect ExecError %s", eerr)
1356	}
1357	expect := "field X in type int"
1358	if !strings.Contains(err.Error(), expect) {
1359		t.Errorf("expected %q; got %q", expect, err)
1360	}
1361}
1362
1363func funcNameTestFunc() int {
1364	return 0
1365}
1366
1367func TestGoodFuncNames(t *testing.T) {
1368	names := []string{
1369		"_",
1370		"a",
1371		"a1",
1372		"a1",
1373		"Ӵ",
1374	}
1375	for _, name := range names {
1376		tmpl := New("X").Funcs(
1377			FuncMap{
1378				name: funcNameTestFunc,
1379			},
1380		)
1381		if tmpl == nil {
1382			t.Fatalf("nil result for %q", name)
1383		}
1384	}
1385}
1386
1387func TestBadFuncNames(t *testing.T) {
1388	names := []string{
1389		"",
1390		"2",
1391		"a-b",
1392	}
1393	for _, name := range names {
1394		testBadFuncName(name, t)
1395	}
1396}
1397
1398func testBadFuncName(name string, t *testing.T) {
1399	t.Helper()
1400	defer func() {
1401		recover()
1402	}()
1403	New("X").Funcs(
1404		FuncMap{
1405			name: funcNameTestFunc,
1406		},
1407	)
1408	// If we get here, the name did not cause a panic, which is how Funcs
1409	// reports an error.
1410	t.Errorf("%q succeeded incorrectly as function name", name)
1411}
1412
1413func TestBlock(t *testing.T) {
1414	const (
1415		input   = `a({{block "inner" .}}bar({{.}})baz{{end}})b`
1416		want    = `a(bar(hello)baz)b`
1417		overlay = `{{define "inner"}}foo({{.}})bar{{end}}`
1418		want2   = `a(foo(goodbye)bar)b`
1419	)
1420	tmpl, err := New("outer").Parse(input)
1421	if err != nil {
1422		t.Fatal(err)
1423	}
1424	tmpl2, err := Must(tmpl.Clone()).Parse(overlay)
1425	if err != nil {
1426		t.Fatal(err)
1427	}
1428
1429	var buf strings.Builder
1430	if err := tmpl.Execute(&buf, "hello"); err != nil {
1431		t.Fatal(err)
1432	}
1433	if got := buf.String(); got != want {
1434		t.Errorf("got %q, want %q", got, want)
1435	}
1436
1437	buf.Reset()
1438	if err := tmpl2.Execute(&buf, "goodbye"); err != nil {
1439		t.Fatal(err)
1440	}
1441	if got := buf.String(); got != want2 {
1442		t.Errorf("got %q, want %q", got, want2)
1443	}
1444}
1445
1446func TestEvalFieldErrors(t *testing.T) {
1447	tests := []struct {
1448		name, src string
1449		value     any
1450		want      string
1451	}{
1452		{
1453			// Check that calling an invalid field on nil pointer
1454			// prints a field error instead of a distracting nil
1455			// pointer error. https://golang.org/issue/15125
1456			"MissingFieldOnNil",
1457			"{{.MissingField}}",
1458			(*T)(nil),
1459			"can't evaluate field MissingField in type *template.T",
1460		},
1461		{
1462			"MissingFieldOnNonNil",
1463			"{{.MissingField}}",
1464			&T{},
1465			"can't evaluate field MissingField in type *template.T",
1466		},
1467		{
1468			"ExistingFieldOnNil",
1469			"{{.X}}",
1470			(*T)(nil),
1471			"nil pointer evaluating *template.T.X",
1472		},
1473		{
1474			"MissingKeyOnNilMap",
1475			"{{.MissingKey}}",
1476			(*map[string]string)(nil),
1477			"nil pointer evaluating *map[string]string.MissingKey",
1478		},
1479		{
1480			"MissingKeyOnNilMapPtr",
1481			"{{.MissingKey}}",
1482			(*map[string]string)(nil),
1483			"nil pointer evaluating *map[string]string.MissingKey",
1484		},
1485		{
1486			"MissingKeyOnMapPtrToNil",
1487			"{{.MissingKey}}",
1488			&map[string]string{},
1489			"<nil>",
1490		},
1491	}
1492	for _, tc := range tests {
1493		t.Run(tc.name, func(t *testing.T) {
1494			tmpl := Must(New("tmpl").Parse(tc.src))
1495			err := tmpl.Execute(io.Discard, tc.value)
1496			got := "<nil>"
1497			if err != nil {
1498				got = err.Error()
1499			}
1500			if !strings.HasSuffix(got, tc.want) {
1501				t.Fatalf("got error %q, want %q", got, tc.want)
1502			}
1503		})
1504	}
1505}
1506
1507func TestMaxExecDepth(t *testing.T) {
1508	if testing.Short() {
1509		t.Skip("skipping in -short mode")
1510	}
1511	tmpl := Must(New("tmpl").Parse(`{{template "tmpl" .}}`))
1512	err := tmpl.Execute(io.Discard, nil)
1513	got := "<nil>"
1514	if err != nil {
1515		got = err.Error()
1516	}
1517	const want = "exceeded maximum template depth"
1518	if !strings.Contains(got, want) {
1519		t.Errorf("got error %q; want %q", got, want)
1520	}
1521}
1522
1523func TestAddrOfIndex(t *testing.T) {
1524	// golang.org/issue/14916.
1525	// Before index worked on reflect.Values, the .String could not be
1526	// found on the (incorrectly unaddressable) V value,
1527	// in contrast to range, which worked fine.
1528	// Also testing that passing a reflect.Value to tmpl.Execute works.
1529	texts := []string{
1530		`{{range .}}{{.String}}{{end}}`,
1531		`{{with index . 0}}{{.String}}{{end}}`,
1532	}
1533	for _, text := range texts {
1534		tmpl := Must(New("tmpl").Parse(text))
1535		var buf strings.Builder
1536		err := tmpl.Execute(&buf, reflect.ValueOf([]V{{1}}))
1537		if err != nil {
1538			t.Fatalf("%s: Execute: %v", text, err)
1539		}
1540		if buf.String() != "&lt;1&gt;" {
1541			t.Fatalf("%s: template output = %q, want %q", text, &buf, "&lt;1&gt;")
1542		}
1543	}
1544}
1545
1546func TestInterfaceValues(t *testing.T) {
1547	// golang.org/issue/17714.
1548	// Before index worked on reflect.Values, interface values
1549	// were always implicitly promoted to the underlying value,
1550	// except that nil interfaces were promoted to the zero reflect.Value.
1551	// Eliminating a round trip to interface{} and back to reflect.Value
1552	// eliminated this promotion, breaking these cases.
1553	tests := []struct {
1554		text string
1555		out  string
1556	}{
1557		{`{{index .Nil 1}}`, "ERROR: index of untyped nil"},
1558		{`{{index .Slice 2}}`, "2"},
1559		{`{{index .Slice .Two}}`, "2"},
1560		{`{{call .Nil 1}}`, "ERROR: call of nil"},
1561		{`{{call .PlusOne 1}}`, "2"},
1562		{`{{call .PlusOne .One}}`, "2"},
1563		{`{{and (index .Slice 0) true}}`, "0"},
1564		{`{{and .Zero true}}`, "0"},
1565		{`{{and (index .Slice 1) false}}`, "false"},
1566		{`{{and .One false}}`, "false"},
1567		{`{{or (index .Slice 0) false}}`, "false"},
1568		{`{{or .Zero false}}`, "false"},
1569		{`{{or (index .Slice 1) true}}`, "1"},
1570		{`{{or .One true}}`, "1"},
1571		{`{{not (index .Slice 0)}}`, "true"},
1572		{`{{not .Zero}}`, "true"},
1573		{`{{not (index .Slice 1)}}`, "false"},
1574		{`{{not .One}}`, "false"},
1575		{`{{eq (index .Slice 0) .Zero}}`, "true"},
1576		{`{{eq (index .Slice 1) .One}}`, "true"},
1577		{`{{ne (index .Slice 0) .Zero}}`, "false"},
1578		{`{{ne (index .Slice 1) .One}}`, "false"},
1579		{`{{ge (index .Slice 0) .One}}`, "false"},
1580		{`{{ge (index .Slice 1) .Zero}}`, "true"},
1581		{`{{gt (index .Slice 0) .One}}`, "false"},
1582		{`{{gt (index .Slice 1) .Zero}}`, "true"},
1583		{`{{le (index .Slice 0) .One}}`, "true"},
1584		{`{{le (index .Slice 1) .Zero}}`, "false"},
1585		{`{{lt (index .Slice 0) .One}}`, "true"},
1586		{`{{lt (index .Slice 1) .Zero}}`, "false"},
1587	}
1588
1589	for _, tt := range tests {
1590		tmpl := Must(New("tmpl").Parse(tt.text))
1591		var buf strings.Builder
1592		err := tmpl.Execute(&buf, map[string]any{
1593			"PlusOne": func(n int) int {
1594				return n + 1
1595			},
1596			"Slice": []int{0, 1, 2, 3},
1597			"One":   1,
1598			"Two":   2,
1599			"Nil":   nil,
1600			"Zero":  0,
1601		})
1602		if strings.HasPrefix(tt.out, "ERROR:") {
1603			e := strings.TrimSpace(strings.TrimPrefix(tt.out, "ERROR:"))
1604			if err == nil || !strings.Contains(err.Error(), e) {
1605				t.Errorf("%s: Execute: %v, want error %q", tt.text, err, e)
1606			}
1607			continue
1608		}
1609		if err != nil {
1610			t.Errorf("%s: Execute: %v", tt.text, err)
1611			continue
1612		}
1613		if buf.String() != tt.out {
1614			t.Errorf("%s: template output = %q, want %q", tt.text, &buf, tt.out)
1615		}
1616	}
1617}
1618
1619// Check that panics during calls are recovered and returned as errors.
1620func TestExecutePanicDuringCall(t *testing.T) {
1621	funcs := map[string]any{
1622		"doPanic": func() string {
1623			panic("custom panic string")
1624		},
1625	}
1626	tests := []struct {
1627		name    string
1628		input   string
1629		data    any
1630		wantErr string
1631	}{
1632		{
1633			"direct func call panics",
1634			"{{doPanic}}", (*T)(nil),
1635			`template: t:1:2: executing "t" at <doPanic>: error calling doPanic: custom panic string`,
1636		},
1637		{
1638			"indirect func call panics",
1639			"{{call doPanic}}", (*T)(nil),
1640			`template: t:1:7: executing "t" at <doPanic>: error calling doPanic: custom panic string`,
1641		},
1642		{
1643			"direct method call panics",
1644			"{{.GetU}}", (*T)(nil),
1645			`template: t:1:2: executing "t" at <.GetU>: error calling GetU: runtime error: invalid memory address or nil pointer dereference`,
1646		},
1647		{
1648			"indirect method call panics",
1649			"{{call .GetU}}", (*T)(nil),
1650			`template: t:1:7: executing "t" at <.GetU>: error calling GetU: runtime error: invalid memory address or nil pointer dereference`,
1651		},
1652		{
1653			"func field call panics",
1654			"{{call .PanicFunc}}", tVal,
1655			`template: t:1:2: executing "t" at <call .PanicFunc>: error calling call: test panic`,
1656		},
1657		{
1658			"method call on nil interface",
1659			"{{.NonEmptyInterfaceNil.Method0}}", tVal,
1660			`template: t:1:23: executing "t" at <.NonEmptyInterfaceNil.Method0>: nil pointer evaluating template.I.Method0`,
1661		},
1662	}
1663	for _, tc := range tests {
1664		b := new(bytes.Buffer)
1665		tmpl, err := New("t").Funcs(funcs).Parse(tc.input)
1666		if err != nil {
1667			t.Fatalf("parse error: %s", err)
1668		}
1669		err = tmpl.Execute(b, tc.data)
1670		if err == nil {
1671			t.Errorf("%s: expected error; got none", tc.name)
1672		} else if !strings.Contains(err.Error(), tc.wantErr) {
1673			if *debug {
1674				fmt.Printf("%s: test execute error: %s\n", tc.name, err)
1675			}
1676			t.Errorf("%s: expected error:\n%s\ngot:\n%s", tc.name, tc.wantErr, err)
1677		}
1678	}
1679}
1680
1681// Issue 31810. Check that a parenthesized first argument behaves properly.
1682func TestIssue31810(t *testing.T) {
1683	t.Skip("broken in html/template")
1684
1685	// A simple value with no arguments is fine.
1686	var b strings.Builder
1687	const text = "{{ (.)  }}"
1688	tmpl, err := New("").Parse(text)
1689	if err != nil {
1690		t.Error(err)
1691	}
1692	err = tmpl.Execute(&b, "result")
1693	if err != nil {
1694		t.Error(err)
1695	}
1696	if b.String() != "result" {
1697		t.Errorf("%s got %q, expected %q", text, b.String(), "result")
1698	}
1699
1700	// Even a plain function fails - need to use call.
1701	f := func() string { return "result" }
1702	b.Reset()
1703	err = tmpl.Execute(&b, f)
1704	if err == nil {
1705		t.Error("expected error with no call, got none")
1706	}
1707
1708	// Works if the function is explicitly called.
1709	const textCall = "{{ (call .)  }}"
1710	tmpl, err = New("").Parse(textCall)
1711	b.Reset()
1712	err = tmpl.Execute(&b, f)
1713	if err != nil {
1714		t.Error(err)
1715	}
1716	if b.String() != "result" {
1717		t.Errorf("%s got %q, expected %q", textCall, b.String(), "result")
1718	}
1719}
1720
1721// Issue 39807. There was a race applying escapeTemplate.
1722
1723const raceText = `
1724{{- define "jstempl" -}}
1725var v = "v";
1726{{- end -}}
1727<script type="application/javascript">
1728{{ template "jstempl" $ }}
1729</script>
1730`
1731
1732func TestEscapeRace(t *testing.T) {
1733	tmpl := New("")
1734	_, err := tmpl.New("templ.html").Parse(raceText)
1735	if err != nil {
1736		t.Fatal(err)
1737	}
1738	const count = 20
1739	for i := 0; i < count; i++ {
1740		_, err := tmpl.New(fmt.Sprintf("x%d.html", i)).Parse(`{{ template "templ.html" .}}`)
1741		if err != nil {
1742			t.Fatal(err)
1743		}
1744	}
1745
1746	var wg sync.WaitGroup
1747	for i := 0; i < 10; i++ {
1748		wg.Add(1)
1749		go func() {
1750			defer wg.Done()
1751			for j := 0; j < count; j++ {
1752				sub := tmpl.Lookup(fmt.Sprintf("x%d.html", j))
1753				if err := sub.Execute(io.Discard, nil); err != nil {
1754					t.Error(err)
1755				}
1756			}
1757		}()
1758	}
1759	wg.Wait()
1760}
1761
1762func TestRecursiveExecute(t *testing.T) {
1763	tmpl := New("")
1764
1765	recur := func() (HTML, error) {
1766		var sb strings.Builder
1767		if err := tmpl.ExecuteTemplate(&sb, "subroutine", nil); err != nil {
1768			t.Fatal(err)
1769		}
1770		return HTML(sb.String()), nil
1771	}
1772
1773	m := FuncMap{
1774		"recur": recur,
1775	}
1776
1777	top, err := tmpl.New("x.html").Funcs(m).Parse(`{{recur}}`)
1778	if err != nil {
1779		t.Fatal(err)
1780	}
1781	_, err = tmpl.New("subroutine").Parse(`<a href="/x?p={{"'a<b'"}}">`)
1782	if err != nil {
1783		t.Fatal(err)
1784	}
1785	if err := top.Execute(io.Discard, nil); err != nil {
1786		t.Fatal(err)
1787	}
1788}
1789
1790// recursiveInvoker is for TestRecursiveExecuteViaMethod.
1791type recursiveInvoker struct {
1792	t    *testing.T
1793	tmpl *Template
1794}
1795
1796func (r *recursiveInvoker) Recur() (string, error) {
1797	var sb strings.Builder
1798	if err := r.tmpl.ExecuteTemplate(&sb, "subroutine", nil); err != nil {
1799		r.t.Fatal(err)
1800	}
1801	return sb.String(), nil
1802}
1803
1804func TestRecursiveExecuteViaMethod(t *testing.T) {
1805	tmpl := New("")
1806	top, err := tmpl.New("x.html").Parse(`{{.Recur}}`)
1807	if err != nil {
1808		t.Fatal(err)
1809	}
1810	_, err = tmpl.New("subroutine").Parse(`<a href="/x?p={{"'a<b'"}}">`)
1811	if err != nil {
1812		t.Fatal(err)
1813	}
1814	r := &recursiveInvoker{
1815		t:    t,
1816		tmpl: tmpl,
1817	}
1818	if err := top.Execute(io.Discard, r); err != nil {
1819		t.Fatal(err)
1820	}
1821}
1822
1823// Issue 43295.
1824func TestTemplateFuncsAfterClone(t *testing.T) {
1825	s := `{{ f . }}`
1826	want := "test"
1827	orig := New("orig").Funcs(map[string]any{
1828		"f": func(in string) string {
1829			return in
1830		},
1831	}).New("child")
1832
1833	overviewTmpl := Must(Must(orig.Clone()).Parse(s))
1834	var out strings.Builder
1835	if err := overviewTmpl.Execute(&out, want); err != nil {
1836		t.Fatal(err)
1837	}
1838	if got := out.String(); got != want {
1839		t.Fatalf("got %q; want %q", got, want)
1840	}
1841}
1842