3 Thank you for your interest in contributing to Rust! There are many ways to
4 contribute, and we appreciate all of them. This document is a bit long, so here's
5 links to the major sections:
7 * [Feature Requests](#feature-requests)
8 * [Bug Reports](#bug-reports)
9 * [The Build System](#the-build-system)
10 * [Pull Requests](#pull-requests)
11 * [Writing Documentation](#writing-documentation)
12 * [Issue Triage](#issue-triage)
13 * [Out-of-tree Contributions](#out-of-tree-contributions)
14 * [Helpful Links and Information](#helpful-links-and-information)
16 If you have questions, please make a post on [internals.rust-lang.org][internals] or
17 hop on [#rust-internals][pound-rust-internals].
19 As a reminder, all contributors are expected to follow our [Code of Conduct][coc].
21 [pound-rust-internals]: http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-internals
22 [internals]: https://internals.rust-lang.org
23 [coc]: https://www.rust-lang.org/conduct.html
27 To request a change to the way that the Rust language works, please open an
28 issue in the [RFCs repository](https://github.com/rust-lang/rfcs/issues/new)
29 rather than this one. New features and other significant language changes
30 must go through the RFC process.
34 While bugs are unfortunate, they're a reality in software. We can't fix what we
35 don't know about, so please report liberally. If you're not sure if something
36 is a bug or not, feel free to file a bug anyway.
38 **If you believe reporting your bug publicly represents a security risk to Rust users,
39 please follow our [instructions for reporting security vulnerabilities](https://www.rust-lang.org/security.html)**.
41 If you have the chance, before reporting a bug, please [search existing
42 issues](https://github.com/rust-lang/rust/search?q=&type=Issues&utf8=%E2%9C%93),
43 as it's possible that someone else has already reported your error. This doesn't
44 always work, and sometimes it's hard to know what to search for, so consider this
45 extra credit. We won't mind if you accidentally file a duplicate report.
47 Opening an issue is as easy as following [this
48 link](https://github.com/rust-lang/rust/issues/new) and filling out the fields.
49 Here's a template that you can use to file a bug, though it's not necessary to
52 <short summary of the bug>
56 <code sample that causes the bug>
58 I expected to see this happen: <explanation>
60 Instead, this happened: <explanation>
64 `rustc --version --verbose`:
68 All three components are important: what you did, what you expected, what
69 happened instead. Please include the output of `rustc --version --verbose`,
70 which includes important information about what platform you're on, what
71 version of Rust you're using, etc.
73 Sometimes, a backtrace is helpful, and so including that is nice. To get
74 a backtrace, set the `RUST_BACKTRACE` environment variable to a value
75 other than `0`. The easiest way
76 to do this is to invoke `rustc` like this:
79 $ RUST_BACKTRACE=1 rustc ...
84 Rust's build system allows you to bootstrap the compiler, run tests &
85 benchmarks, generate documentation, install a fresh build of Rust, and more.
86 It's your best friend when working on Rust, allowing you to compile & test
87 your contributions before submission.
89 All the configuration for the build system lives in [the `mk` directory][mkdir]
90 in the project root. It can be hard to follow in places, as it uses some
91 advanced Make features which make for some challenging reading. If you have
92 questions on the build system internals, try asking in
93 [`#rust-internals`][pound-rust-internals].
95 [mkdir]: https://github.com/rust-lang/rust/tree/master/mk/
99 Before you can start building the compiler you need to configure the build for
100 your system. In most cases, that will just mean using the defaults provided
101 for Rust. Configuring involves invoking the `configure` script in the project
108 There are large number of options accepted by this script to alter the
109 configuration used later in the build process. Some options to note:
111 - `--enable-debug` - Build a debug version of the compiler (disables optimizations)
112 - `--enable-optimize` - Enable optimizations (can be used with `--enable-debug`
113 to make a debug build with optimizations)
114 - `--disable-valgrind-rpass` - Don't run tests with valgrind
115 - `--enable-clang` - Prefer clang to gcc for building dependencies (e.g., LLVM)
116 - `--enable-ccache` - Invoke clang/gcc with ccache to re-use object files between builds
117 - `--enable-compiler-docs` - Build compiler documentation
119 To see a full list of options, run `./configure --help`.
123 Some common make targets are:
125 - `make rustc-stage1` - build up to (and including) the first stage. For most
126 cases we don't need to build the stage2 compiler, so we can save time by not
127 building it. The stage1 compiler is a fully functioning compiler and
128 (probably) will be enough to determine if your change works as expected.
129 - `make check` - build the full compiler & run all tests (takes a while). This
130 is what gets run by the continuous integration system against your pull
131 request. You should run this before submitting to make sure your tests pass
132 & everything builds in the correct manner.
133 - `make check-stage1-std NO_REBUILD=1` - test the standard library without
134 rebuilding the entire compiler
135 - `make check TESTNAME=<substring-of-test-name>` - Run a matching set of tests.
136 - `TESTNAME` should be a substring of the tests to match against e.g. it could
137 be the fully qualified test name, or just a part of it.
138 `TESTNAME=collections::hash::map::test_map::test_capacity_not_less_than_len`
139 or `TESTNAME=test_capacity_not_less_than_len`.
140 - `make check-stage1-rpass TESTNAME=<substring-of-test-name>` - Run a single
141 rpass test with the stage1 compiler (this will be quicker than running the
142 command above as we only build the stage1 compiler, not the entire thing).
143 You can also leave off the `-rpass` to run all stage1 test types.
144 - `make check-stage1-coretest` - Run stage1 tests in `libcore`.
148 Pull requests are the primary mechanism we use to change Rust. GitHub itself
149 has some [great documentation][pull-requests] on using the Pull Request
150 feature. We use the 'fork and pull' model described there.
152 [pull-requests]: https://help.github.com/articles/using-pull-requests/
154 Please make pull requests against the `master` branch.
156 Compiling all of `make check` can take a while. When testing your pull request,
157 consider using one of the more specialized `make` targets to cut down on the
158 amount of time you have to wait. You need to have built the compiler at least
159 once before running these will work, but that’s only one full build rather than
162 $ make -j8 rustc-stage1 && make check-stage1
164 is one such example, which builds just `rustc`, and then runs the tests. If
165 you’re adding something to the standard library, try
167 $ make -j8 check-stage1-std NO_REBUILD=1
169 This will not rebuild the compiler, but will run the tests.
171 All pull requests are reviewed by another person. We have a bot,
172 @rust-highfive, that will automatically assign a random person to review your
175 If you want to request that a specific person reviews your pull request,
176 you can add an `r?` to the message. For example, Steve usually reviews
177 documentation changes. So if you were to make a documentation change, add
181 to the end of the message, and @rust-highfive will assign @steveklabnik instead
182 of a random person. This is entirely optional.
184 After someone has reviewed your pull request, they will leave an annotation
185 on the pull request with an `r+`. It will look something like this:
189 This tells @bors, our lovable integration bot, that your pull request has
190 been approved. The PR then enters the [merge queue][merge-queue], where @bors
191 will run all the tests on every platform we support. If it all works out,
192 @bors will merge your code into `master` and close the pull request.
194 [merge-queue]: http://buildbot.rust-lang.org/homu/queue/rust
196 Speaking of tests, Rust has a comprehensive test suite. More information about
198 [here](https://github.com/rust-lang/rust-wiki-backup/blob/master/Note-testsuite.md).
200 ## Writing Documentation
202 Documentation improvements are very welcome. The source of `doc.rust-lang.org`
203 is located in `src/doc` in the tree, and standard API documentation is generated
204 from the source code itself.
206 Documentation pull requests function in the same way as other pull requests,
207 though you may see a slightly different form of `r+`:
209 @bors: r+ 38fe8d2 rollup
211 That additional `rollup` tells @bors that this change is eligible for a 'rollup'.
212 To save @bors some work, and to get small changes through more quickly, when
213 @bors attempts to merge a commit that's rollup-eligible, it will also merge
214 the other rollup-eligible patches too, and they'll get tested and merged at
217 To find documentation-related issues, sort by the [A-docs label][adocs].
219 [adocs]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AA-docs
221 In many cases, you don't need a full `make doc`. You can use `rustdoc` directly
222 to check small fixes. For example, `rustdoc src/doc/reference.md` will render
223 reference to `doc/reference.html`. The CSS might be messed up, but you can
224 verify that HTML is right.
228 Sometimes, an issue will stay open, even though the bug has been fixed. And
229 sometimes, the original bug may go stale because something has changed in the
232 It can be helpful to go through older bug reports and make sure that they are
233 still valid. Load up an older issue, double check that it's still true, and
234 leave a comment letting us know if it is or is not. The [least recently
235 updated sort][lru] is good for finding issues like this.
237 Contributors with sufficient permissions on the Rust repo can help by adding
238 labels to triage issues:
240 * Yellow, **A**-prefixed labels state which **area** of the project an issue
243 * Magenta, **B**-prefixed labels identify bugs which are **blockers**.
245 * Green, **E**-prefixed labels explain the level of **experience** necessary
248 * Red, **I**-prefixed labels indicate the **importance** of the issue. The
249 [I-nominated][inom] label indicates that an issue has been nominated for
250 prioritizing at the next triage meeting.
252 * Orange, **P**-prefixed labels indicate a bug's **priority**. These labels
253 are only assigned during triage meetings, and replace the [I-nominated][inom]
256 * Blue, **T**-prefixed bugs denote which **team** the issue belongs to.
258 * Dark blue, **beta-** labels track changes which need to be backported into
261 * The purple **metabug** label marks lists of bugs collected by other
264 If you're looking for somewhere to start, check out the [E-easy][eeasy] tag.
266 [inom]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AI-nominated
267 [eeasy]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AE-easy
268 [lru]: https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-asc
270 ## Out-of-tree Contributions
272 There are a number of other ways to contribute to Rust that don't deal with
275 Answer questions in [#rust][pound-rust], or on [users.rust-lang.org][users],
276 or on [StackOverflow][so].
278 Participate in the [RFC process](https://github.com/rust-lang/rfcs).
280 Find a [requested community library][community-library], build it, and publish
281 it to [Crates.io](http://crates.io). Easier said than done, but very, very
284 [pound-rust]: http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust
285 [users]: https://users.rust-lang.org/
286 [so]: http://stackoverflow.com/questions/tagged/rust
287 [community-library]: https://github.com/rust-lang/rfcs/labels/A-community-library
289 ## Helpful Links and Information
291 For people new to Rust, and just starting to contribute, or even for
292 more seasoned developers, some useful places to look for information
295 * The [Rust Internals forum][rif], a place to ask questions and
296 discuss Rust's internals
297 * The [generated documentation for rust's compiler][gdfrustc]
298 * The [rust reference][rr], even though it doesn't specifically talk about Rust's internals, it's a great resource nonetheless
299 * Although out of date, [Tom Lee's great blog article][tlgba] is very helpful
300 * [rustaceans.org][ro] is helpful, but mostly dedicated to IRC
301 * The [Rust Compiler Testing Docs][rctd]
302 * For @bors, [this cheat sheet][cheatsheet] is helpful (Remember to replace `@homu` with `@bors` in the commands that you use.)
303 * **Google!** ([search only in Rust Documentation][gsearchdocs] to find types, traits, etc. quickly)
304 * Don't be afraid to ask! The Rust community is friendly and helpful.
306 [gdfrustc]: http://manishearth.github.io/rust-internals-docs/rustc/
307 [gsearchdocs]: https://www.google.com/search?q=site:doc.rust-lang.org+your+query+here
308 [rif]: http://internals.rust-lang.org
309 [rr]: https://doc.rust-lang.org/book/README.html
310 [tlgba]: http://tomlee.co/2014/04/03/a-more-detailed-tour-of-the-rust-compiler/
311 [ro]: http://www.rustaceans.org/
312 [rctd]: ./COMPILER_TESTS.md
313 [cheatsheet]: http://buildbot.rust-lang.org/homu/