| <!-- Contributing to the Go project --> |
| |
| <h2 id="Introduction">Introduction</h2> |
| |
| <p> |
| This document explains how to contribute changes to the Go project. |
| It assumes you have installed Go using the |
| <a href="install.html">installation instructions</a> and |
| have <a href="code.html">written and tested your code</a>. |
| (Note that the <code>gccgo</code> frontend lives elsewhere; |
| see <a href="gccgo_contribute.html">Contributing to gccgo</a>.) |
| </p> |
| |
| <h2 id="Design">Discuss your design</h2> |
| |
| <p> |
| The project welcomes submissions but please let everyone know what |
| you're working on if you want it to become part of the main repository. |
| </p> |
| |
| <p> |
| Before undertaking to write something new for the Go project, send |
| mail to the <a href="http://groups.google.com/group/golang-nuts">mailing |
| list</a> to discuss what you plan to do. This gives everyone a |
| chance to validate the design, helps prevent duplication of effort, |
| and ensures that the idea fits inside the goals for the language |
| and tools. It also guarantees that the design is sound before code |
| is written; the code review tool is not the place for high-level |
| discussions. |
| </p> |
| |
| <p> |
| In short, send mail before you code. |
| And don't start the discussion by mailing a change list! |
| </p> |
| |
| <h2 id="Testing">Testing redux</h2> |
| |
| <p> |
| You've <a href="code.html">written and tested your code</a>, but |
| before sending code out for review, run all the tests for the whole |
| tree to make sure the changes don't break other packages or programs: |
| </p> |
| |
| <pre> |
| cd $GOROOT/src |
| make all |
| </pre> |
| |
| <p> |
| The final line printed by <code>make all</code> should be of the form: |
| </p> |
| |
| <pre> |
| <i>N</i> known bugs; 0 unexpected bugs |
| </pre> |
| |
| <p> |
| The value of <i>N</i> varies over time, but the line must |
| say “<code>0 unexpected bugs</code>” and must not |
| add “<code>test output differs</code>.” |
| </p> |
| |
| |
| <h2 id="Code_review">Code review</h2> |
| |
| <p> |
| Changes to Go must be reviewed before they are submitted, |
| no matter who makes the change. |
| (In exceptional cases, such as fixing a build, the review can |
| follow shortly after submitting.) |
| A Mercurial extension helps manage the code review process. |
| The extension is included in the Go source tree but needs |
| to be added to your Mercurial configuration. |
| </p> |
| |
| <h3>Caveat for Mercurial aficionados</h3> |
| |
| <p> |
| <i>Using Mercurial with the code review extension is not the same |
| as using standard Mercurial.</i> |
| </p> |
| |
| <p> |
| The Go repository is maintained as a single line of reviewed changes; |
| we prefer to avoid the complexity of Mercurial's arbitrary change graph. |
| The code review extension helps here: its <code>hg submit</code> command |
| automatically checks for and warns about the local repository |
| being out of date compared to the remote one. |
| The <code>hg submit</code> command also verifies other |
| properties about the Go repository. |
| For example, |
| it checks that Go code being checked in is formatted in the standard style, |
| as defined by <a href="/cmd/gofmt">gofmt</a>, |
| and it checks that the author of the code is properly recorded for |
| <a href="#copyright">copyright purposes</a>. |
| </p> |
| |
| <p> |
| To help ensure changes are only created by <code>hg submit</code>, |
| the code review extension disables the standard <code>hg commit</code> |
| command. |
| </p> |
| |
| <p> |
| Mercurial power users: To allow Go contributors to take advantage of |
| Mercurial's functionality for local revision control, it might be interesting |
| to explore how the code review extension can be made to work alongside |
| the Mercurial Queues extension. |
| </p> |
| |
| <h3>Configure the extension</h3> |
| |
| <p>Edit <code>$GOROOT/.hg/hgrc</code> to add:</p> |
| |
| <pre> |
| [extensions] |
| codereview = YOUR_GO_ROOT/lib/codereview/codereview.py |
| |
| [ui] |
| username = Your Name <you@server.dom> |
| </pre> |
| |
| <p>Replace YOUR_GO_ROOT with the value of <code>$GOROOT</code>. |
| The Mercurial configuration file format does not allow environment variable substitution. |
| The <code>username</code> information will not be used unless |
| you are a committer (see below), but Mercurial complains if it is missing. |
| </p> |
| |
| <h3>Log in to the code review site.</h3> |
| |
| <p> |
| The code review server uses a Google Account to authenticate. |
| (If you can use the account to |
| <a href="https://www.google.com/accounts/Login?hl=en&continue=http://www.google.com/">sign in at google.com</a>, |
| you can use it to sign in to the code review server. |
| The email address you use on the Code Review site |
| will be recorded in the <a href="http://code.google.com/p/go/source/list">Mercurial change log</a> |
| and in the <a href="/CONTRIBUTORS"><code>CONTRIBUTORS</code></a> file. |
| You can <a href="https://www.google.com/accounts/NewAccount">create a Google Account</a> |
| associated with any address where you receive email. |
| </p> |
| |
| <pre> |
| $ cd $GOROOT |
| $ hg code-login |
| Email (login for uploading to codereview.appspot.com): rsc@golang.org |
| Password for rsc@golang.org: |
| |
| Saving authentication cookies to /Users/rsc/.codereview_upload_cookies_codereview.appspot.com |
| </pre> |
| |
| <h3>Configure your account settings.</h3> |
| |
| <p>Edit your <a href="http://codereview.appspot.com/settings">code review settings</a>. |
| Grab a nickname. |
| Many people prefer to set the Context option to |
| “Whole file” to see more context when reviewing changes. |
| </p> |
| |
| <p>Once you have chosen a nickname in the settings page, others |
| can use that nickname as a shorthand for naming reviewers and the CC list. |
| For example, <code>rsc</code> is an alias for <code>rsc@golang.org</code>. |
| </p> |
| |
| <h3>Make a change</h3> |
| |
| <p> |
| The entire checked-out tree is writable. |
| If you need to edit files, just edit them: Mercurial will figure out which ones changed. |
| You do need to inform Mercurial of added, removed, copied, or renamed files, |
| by running |
| <code>hg add</code>, |
| <code>hg rm</code>, |
| <code>hg cp</code>, |
| or |
| <code>hg mv</code>. |
| </p> |
| |
| <p>When you are ready to send a change out for review, run</p> |
| |
| <pre> |
| $ hg change |
| </pre> |
| |
| <p>from any directory in your Go repository. |
| Mercurial will open a change description file in your editor. |
| (It uses the editor named by the <code>$EDITOR</code> environment variable, <code>vi</code> by default.) |
| The file will look like: |
| </p> |
| |
| <pre> |
| # Change list. |
| # Lines beginning with # are ignored. |
| # Multi-line values should be indented. |
| |
| Reviewer: |
| CC: |
| |
| Description: |
| <enter description here> |
| |
| Files: |
| src/pkg/math/sin.go |
| src/pkg/math/tan.go |
| src/pkg/regexp/regexp.go |
| </pre> |
| |
| <p> |
| The <code>Reviewer</code> line lists the reviewers assigned |
| to this change, and the <code>CC</code> line lists people to |
| notify about the change. |
| These can be code review nicknames or arbitrary email addresses. |
| If you don't know who is best to review the change, set the |
| reviewer field to the |
| <a href="http://groups.google.com/group/golang-dev">golang-dev@googlegroups.com</a> |
| mailing list. |
| </p> |
| |
| <p> |
| Replace “<code><enter description here></code>” |
| with a description of your change. |
| The first line of the change description is conventionally |
| a one-line summary of the change and is used as the |
| subject for code review mail; the rest of the |
| description elaborates. |
| </p> |
| |
| <p> |
| The <code>Files</code> section lists all the modified files |
| in your client. |
| It is best to keep unrelated changes in different change lists. |
| In this example, we can include just the changes to package <code>math</code> |
| by deleting the line mentioning <code>regexp.go</code>. |
| </p> |
| |
| <p> |
| After editing, the template might now read: |
| </p> |
| |
| <pre> |
| # Change list. |
| # Lines beginning with # are ignored. |
| # Multi-line values should be indented. |
| |
| Reviewer: golang-dev@googlegroups.com |
| CC: math-nuts@swtch.com |
| |
| Description: |
| Sin, Cos, Tan: improved precision for very large arguments |
| |
| See Bimmler and Shaney, ``Extreme sinusoids,'' J. Math 3(14). |
| Fixes issue 159. |
| |
| Files: |
| src/pkg/math/sin.go |
| src/pkg/math/tan.go |
| </pre> |
| |
| <p> |
| The special sentence “Fixes issue 159.” associates |
| the change with issue 159 in the <a href="http://code.google.com/p/go/issues/list">Go issue tracker</a>. |
| When this change is eventually submitted, the issue |
| tracker will automatically mark the issue as fixed. |
| </p> |
| |
| <p> |
| Save the file and exit the editor.</p> |
| |
| <p> |
| The code review server assigns your change an issue number and URL, |
| which <code>hg change</code> will print, something like: |
| </p> |
| |
| <pre> |
| CL created: http://codereview.appspot.com/99999 |
| </pre> |
| |
| <p> |
| If you need to re-edit the change description, |
| run <code>hg change 99999</code>. |
| </p> |
| |
| <p> |
| You can see a list of your pending changes by running <code>hg pending</code> (<code>hg p</code> for short). |
| </p> |
| |
| |
| <h3>Synchronize your client</h3> |
| |
| <p>While you were working, others might have submitted changes |
| to the repository. To update your client, run</p> |
| |
| <pre> |
| $ hg sync |
| </pre> |
| |
| <p>(For Mercurial fans, <code>hg sync</code> runs <code>hg pull -u</code> |
| but then also synchronizes the local change list state against the new data.)</p> |
| |
| <p> |
| If files you were editing have changed, Mercurial does its best to merge the |
| remote changes into your local changes. It may leave some files to merge by hand. |
| </p> |
| |
| <p> |
| For example, suppose you have edited <code>flag_test.go</code> but |
| someone else has committed an independent change. |
| When you run <code>hg sync</code>, you will get the (scary-looking) output |
| (emphasis added): |
| |
| <pre> |
| $ hg sync |
| adding changesets |
| adding manifests |
| adding file changes |
| added 1 changeset with 2 changes to 2 files |
| getting src/pkg/flag/flag.go |
| couldn't find merge tool hgmerge |
| merging src/pkg/flag/flag_test.go |
| warning: conflicts during merge. |
| <i>merging src/pkg/flag/flag_test.go failed!</i> |
| 1 file updated, 0 files merged, 0 files removed, 1 file unresolved |
| use 'hg resolve' to retry unresolved file merges |
| $ |
| </pre> |
| |
| <p> |
| The only important part in that transcript is the italicized line: |
| Mercurial failed to merge your changes with the independent change. |
| When this happens, Mercurial leaves both edits in the file, |
| marked by <code><<<<<<<</code> and |
| <code>>>>>>>></code>. |
| it is now your job to edit the file to combine them. |
| Continuing the example, searching for those strings in <code>flag_test.go</code> |
| might turn up: |
| </p> |
| |
| <pre> |
| VisitAll(visitor); |
| <<<<<<< local |
| if len(m) != 7 { |
| ======= |
| if len(m) != 8 { |
| >>>>>>> other |
| t.Error("VisitAll misses some flags"); |
| </pre> |
| |
| <p> |
| Mercurial doesn't show it, but suppose the original text that both edits |
| started with was 6; you added 1 and the other change added 2, |
| so the correct answer might now be 9. First, edit the section |
| to remove the markers and leave the correct code: |
| </p> |
| |
| <pre> |
| VisitAll(visitor); |
| if len(m) != 9 { |
| t.Error("VisitAll misses some flags"); |
| </pre> |
| |
| <p> |
| Then ask Mercurial to mark the conflict as resolved: |
| </p> |
| |
| <pre> |
| $ hg resolve -m flag_test.go |
| </pre> |
| |
| <p> |
| If you had been editing the file, say for debugging, but do not |
| care to preserve your changes, you can run |
| <code>hg revert flag_test.go</code> to abandon your |
| changes, but you may still need to run |
| <code>hg resolve -m</code> to mark the conflict resolved. |
| </p> |
| |
| <h3>Mail the change for review</h3> |
| |
| <p>To send out a change for review, run <code>hg mail</code> using the change list number |
| assigned during <code>hg change</code>:</p> |
| |
| <pre> |
| $ hg mail 99999 |
| </pre> |
| |
| <p>You can add to the <code>Reviewer:</code> and <code>CC:</code> lines |
| using the <code>-r</code> or <code>--cc</code> options. |
| In the above example, we could have left the <code>Reviewer</code> and <code>CC</code> |
| lines blank and then run: |
| </p> |
| |
| <pre> |
| $ hg mail -r golang-dev@googlegroups.com --cc math-nuts@swtch.com 99999 |
| </pre> |
| |
| <p>to achieve the same effect.</p> |
| |
| <p>Note that <code>-r</code> and <code>--cc</code> cannot be spelled <code>--r</code> or <code>-cc</code>.</p> |
| |
| |
| <h3>Reviewing code</h3> |
| |
| <p> |
| Running <code>hg mail</code> will send an email to you and the reviewers |
| asking them to visit the issue's URL and make coments on the change. |
| When done, the reviewer clicks “Publish and Mail comments” |
| to send comments back. |
| </p> |
| |
| |
| <h3>Revise and upload</h3> |
| |
| <p>You will probably revise your code in response to the reviewer comments. |
| When you have revised the code and are ready for another round of review, run |
| </p> |
| |
| <pre> |
| $ hg mail 99999 |
| </pre> |
| |
| <p>again to upload the latest copy and send mail asking the reviewers to please take another look |
| (<code>PTAL</code>). |
| You might also visit the code review web page and reply to the comments, |
| letting the reviewer know that you've addressed them or explain why you |
| haven't. When you're done replying, click “Publish and Mail comments” |
| to send the line-by-line replies and any other comments. |
| </p> |
| <p> |
| The reviewer can comment on the new copy, and the process repeats. |
| The reviewer approves the change by replying with a mail that says |
| <code>LGTM</code>: looks good to me. |
| </p> |
| |
| <h3>Submit the change after the review</h3> |
| |
| <p> |
| After the code has been <code>LGTM</code>'ed, it is time to submit |
| it to the Mercurial repository. |
| If you are a committer, you can run: |
| </p> |
| |
| <pre> |
| $ hg submit 99999 |
| </pre> |
| |
| <p> |
| This checks the change into the repository. |
| The change description will include a link to the code review, |
| and the code review will be updated with a link to the change |
| in the repository. |
| </p> |
| |
| <p> |
| If your local copy of the repository is out of date, |
| <code>hg submit</code> |
| will refuse the change: |
| </p> |
| |
| <pre> |
| $ hg submit 99999 |
| local repository out of date; must sync before submit |
| </pre> |
| |
| <p> |
| If you are not a committer, you cannot submit the change directly. |
| Instead, a committer, usually the reviewer who said <code>LGTM</code>, |
| will run: |
| </p> |
| |
| <pre> |
| $ hg clpatch 99999 |
| $ hg submit 99999 |
| </pre> |
| |
| <p>The <code>clpatch</code> command imports your change 99999 into |
| the committer's local Mercurial client, at which point the committer |
| can check or test the code more. |
| (Anyone can run <code>clpatch</code> to try a change that |
| has been uploaded to the code review server.) |
| The <code>submit</code> command submits the code. You will be listed as the |
| author, but the change message will also indicate who the committer was. |
| Your local client will notice that the change has been submitted |
| when you next run <code>hg sync</code>. |
| </p> |
| |
| |
| <h3 id="copyright">Copyright</h3> |
| |
| <p>Files in the Go repository don't list author names, |
| both to avoid clutter and to avoid having to keep the lists up to date. |
| Instead, your name will appear in the <a href="http://code.google.com/p/go/source/list">Mercurial change log</a> |
| and in the <a href="/CONTRIBUTORS"><code>CONTRIBUTORS</code></a> file |
| and perhaps the <a href="/AUTHORS"><code>AUTHORS</code></a> file. |
| </p> |
| |
| <p>The <a href="/CONTRIBUTORS"><code>CONTRIBUTORS</code></a> file |
| defines who the Go contributors—the people—are; |
| the <a href="/AUTHORS"><code>AUTHORS</code></a> file, which defines |
| who “The Go Authors”—the copyright holders—are. |
| The Go developers at Google will update these files when submitting |
| your first change. |
| In order for them to do that, you need to have completed one of the |
| contributor license agreements: |
| <ul> |
| <li> |
| If you are the copyright holder, you will need to agree to |
| the <a href="http://code.google.com/legal/individual-cla-v1.0.html">individual |
| contributor license agreement</a>, which can be completed online. |
| </li> |
| <li> |
| If your organization is the copyright holder, the organization |
| will need to agree to the <a href="http://code.google.com/legal/corporate-cla-v1.0.html">corporate contributor license agreement</a>. |
| (If the copyright holder for your code has already completed the |
| agreement in connection with another Google open source project, |
| it does not need to be completed again.) |
| </li> |
| </ul> |
| |
| <p> |
| This rigmarole needs to be done only for your first submission. |
| </p> |
| |
| <p>Code that you contribute should use the standard copyright header:</p> |
| |
| <pre> |
| // Copyright 2010 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| </pre> |