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1How to submit a patch
2=====================
3
4
5Configure git
6-------------
7
8<!--?prettify lang=sh?-->
9
10    git config --global user.name "Your Name"
11    git config --global user.email you@example.com
12
13Making changes
14--------------
15
16First create a branch for your changes:
17
18<!--?prettify lang=sh?-->
19
20    git config branch.autosetuprebase always
21    git checkout -b my_feature origin/master
22
23After making your changes, create a commit
24
25<!--?prettify lang=sh?-->
26
27    git add [file1] [file2] ...
28    git commit
29
30If your branch gets out of date, you will need to update it:
31
32<!--?prettify lang=sh?-->
33
34    git pull
35    python tools/git-sync-deps
36
37Adding a unit test
38------------------
39
40If you are willing to change Skia codebase, it's nice to add a test at the same
41time. Skia has a simple unittest framework so you can add a case to it.
42
43Test code is located under the 'tests' directory.
44
45See [Writing Unit and Rendering Tests](../testing/tests) for details.
46
47Unit tests are best, but if your change touches rendering and you can't think of
48an automated way to verify the results, consider writing a GM test or a new page
49of SampleApp. Also, if your change is the GPU code, you may not be able to write
50it as part of the standard unit test suite, but there are GPU-specific testing
51paths you can extend.
52
53Submitting a patch
54------------------
55
56For your code to be accepted into the codebase, you must complete the
57[Individual Contributor License
58Agreement](http://code.google.com/legal/individual-cla-v1.0.html). You can do
59this online, and it only takes a minute. If you are contributing on behalf of a
60corporation, you must fill out the [Corporate Contributor License
61Agreement](http://code.google.com/legal/corporate-cla-v1.0.html)
62and send it to us as described on that page. Add your (or your organization's)
63name and contact info to the AUTHORS file as a part of your CL.
64
65Now that you've made a change and written a test for it, it's ready for the code
66review! Submit a patch and getting it reviewed is fairly easy with depot tools.
67
68Use `git-cl`, which comes with [depot
69tools](http://sites.google.com/a/chromium.org/dev/developers/how-tos/install-depot-tools).
70For help, run `git cl help`.
71
72### Find a reviewer
73
74Ideally, the reviewer is someone who is familiar with the area of code you are
75touching. If you have doubts, look at the git blame for the file to see who else
76has been editing it.
77
78### Uploading changes for review
79
80Skia uses the Gerrit code review tool. Skia's instance is [skia-review](http://skia-review.googlesource.com).
81Use `git cl` to upload your change:
82
83<!--?prettify lang=sh?-->
84
85    git cl upload
86
87You may have to enter a Google Account username and password to authenticate
88yourself to Gerrit. A free gmail account will do fine, or any
89other type of Google account.  It does not have to match the email address you
90configured using `git config --global user.email` above, but it can.
91
92The command output should include a URL, similar to
93(https://skia-review.googlesource.com/c/4559/), indicating where your changelist
94can be reviewed.
95
96### Submit try jobs
97
98Skia's trybots allow testing and verification of changes before they land in the
99repo. You need to have permission to trigger try jobs; if you need permission,
100ask a committer. After uploading your CL to [Gerrit](https://skia-review.googlesource.com/),
101you may trigger a try job for any job listed in tasks.json, either via the
102Gerrit UI, using `git cl try`, eg.
103
104    git cl try -B skia.primary -b Some-Tryjob-Name
105
106or using bin/try, a small wrapper for `git cl try` which helps to choose try jobs.
107From a Skia checkout:
108
109    bin/try --list
110
111You can also search using regular expressions:
112
113    bin/try "Test.*GTX660.*Release"
114
115For more information about testing, see [testing infrastructure](https://skia.org/dev/testing/automated_testing).
116
117### Request review
118
119Go to the supplied URL or go to the code review page and select the **Your**
120dropdown and click on **Changes**. Select the change you want to submit for
121review and click **Reply**. Enter at least one reviewer's email address. Now
122add any optional notes, and send your change off for review by clicking on
123**Send**. Unless you send your change to reviewers, no one will know to look
124at it.
125
126_Note_: If you don't see editing commands on the review page, click **Sign in**
127in the upper right. _Hint_: You can add -r reviewer@example.com --send-mail to
128send the email directly when uploading a change using `git-cl`.
129
130
131The review process
132------------------
133
134If you submit a giant patch, or do a bunch of work without discussing it with
135the relevant people, you may have a hard time convincing anyone to review it!
136
137Code reviews are an important part of the engineering process. The reviewer will
138almost always have suggestions or style fixes for you, and it's important not to
139take such suggestions personally or as a commentary on your abilities or ideas.
140This is a process where we work together to make sure that the highest quality
141code gets submitted!
142
143You will likely get email back from the reviewer with comments. Fix these and
144update the patch set in the issue by uploading again. The upload will explain
145that it is updating the current CL and ask you for a message explaining the
146change. Be sure to respond to all comments before you request review of an
147update.
148
149If you need to update code the code on an already uploaded CL, simply edit the
150code, commit it again locally, and then run git cl upload again e.g.
151
152    echo "GOATS" > whitespace.txt
153    git add whitespace.txt
154    git commit -m 'add GOATS fix to whitespace.txt'
155    git cl upload
156
157Once you're ready for another review, use **Reply** again to send another
158notification (it is helpful to tell the reviewer what you did with respect to
159each of their comments). When the reviewer is happy with your patch, they will
160approve your change by setting the Code-Review label to "+1".
161
162_Note_: As you work through the review process, both you and your reviewers
163should converse using the code review interface, and send notes.
164
165Once your change has received an approval, you can click the "Submit to CQ"
166button on the codereview page and it will be committed on your behalf.
167
168Once your commit has gone in, you should delete the branch containing your change:
169
170    git checkout -q origin/master
171    git branch -D my_feature
172
173
174Final Testing
175-------------
176
177Skia's principal downstream user is Chromium, and any change to Skia rendering
178output can break Chromium. If your change alters rendering in any way, you are
179expected to test for and alleviate this. You may be able to find a Skia team
180member to help you, but the onus remains on each individual contributor to avoid
181breaking Chrome.
182
183### Evaluating Impact on Chromium
184
185Keep in mind that Skia is rolled daily into Blink and Chromium.  Run local tests
186and watch canary bots for results to ensure no impact.  If you are submitting
187changes that will impact layout tests, follow the guides below and/or work with
188your friendly Skia-Blink engineer to evaluate, rebaseline, and land your
189changes.
190
191Resources:
192
193[How to land Skia changes that change Blink layout test results](../chrome/layouttest)
194
195If you're changing the Skia API, you may need to make an associated change in Chromium.
196If you do, please follow these instructions: [Landing Skia changes which require Chrome changes](../chrome/changes)
197
198
199Check in your changes
200---------------------
201
202### Non-Skia-committers
203
204If you already have committer rights, you can follow the directions below to
205commit your change directly to Skia's repository.
206
207If you don't have committer rights in https://skia.googlesource.com/skia.git ...
208first of all, thanks for submitting your patch!  We really appreciate these
209submissions.  After receiving an approval from a committer, you will be able to
210click the "Submit to CQ" button and submit your patch via the commit queue.
211
212In special instances, a Skia committer may assist you in landing the change
213by uploading a new codereview containing your patch (perhaps with some small
214adjustments at his/her discretion).  If so, you can mark your change as
215"Abandoned", and update it with a link to the new codereview.
216
217### Skia committers
218  *  tips on how to apply an externally provided patch are [here](./patch)
219  *  when landing externally contributed patches, please note the original
220     contributor's identity (and provide a link to the original codereview) in the commit message
221
222    `git-cl` will squash all your commits into a single one with the description you used when you uploaded your change.
223
224    ~~~~
225    git cl land
226    ~~~~
227
228    or
229
230    ~~~~
231    git cl land -c 'Contributor Name <email@example.com>'
232    ~~~~
233