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 tips` - show useful targets, variables and other tips for working with
127 - `make rustc-stage1` - build up to (and including) the first stage. For most
128 cases we don't need to build the stage2 compiler, so we can save time by not
129 building it. The stage1 compiler is a fully functioning compiler and
130 (probably) will be enough to determine if your change works as expected.
131 - `make check` - build the full compiler & run all tests (takes a while). This
132 is what gets run by the continuous integration system against your pull
133 request. You should run this before submitting to make sure your tests pass
134 & everything builds in the correct manner.
135 - `make check-stage1-std NO_REBUILD=1` - test the standard library without
136 rebuilding the entire compiler
137 - `make check TESTNAME=<substring-of-test-name>` - Run a matching set of tests.
138 - `TESTNAME` should be a substring of the tests to match against e.g. it could
139 be the fully qualified test name, or just a part of it.
140 `TESTNAME=collections::hash::map::test_map::test_capacity_not_less_than_len`
141 or `TESTNAME=test_capacity_not_less_than_len`.
142 - `make check-stage1-rpass TESTNAME=<substring-of-test-name>` - Run a single
143 rpass test with the stage1 compiler (this will be quicker than running the
144 command above as we only build the stage1 compiler, not the entire thing).
145 You can also leave off the `-rpass` to run all stage1 test types.
146 - `make check-stage1-coretest` - Run stage1 tests in `libcore`.
150 Pull requests are the primary mechanism we use to change Rust. GitHub itself
151 has some [great documentation][pull-requests] on using the Pull Request
152 feature. We use the 'fork and pull' model described there.
154 [pull-requests]: https://help.github.com/articles/using-pull-requests/
156 Please make pull requests against the `master` branch.
158 Compiling all of `make check` can take a while. When testing your pull request,
159 consider using one of the more specialized `make` targets to cut down on the
160 amount of time you have to wait. You need to have built the compiler at least
161 once before running these will work, but that’s only one full build rather than
164 $ make -j8 rustc-stage1 && make check-stage1
166 is one such example, which builds just `rustc`, and then runs the tests. If
167 you’re adding something to the standard library, try
169 $ make -j8 check-stage1-std NO_REBUILD=1
171 This will not rebuild the compiler, but will run the tests.
173 All pull requests are reviewed by another person. We have a bot,
174 @rust-highfive, that will automatically assign a random person to review your
177 If you want to request that a specific person reviews your pull request,
178 you can add an `r?` to the message. For example, Steve usually reviews
179 documentation changes. So if you were to make a documentation change, add
183 to the end of the message, and @rust-highfive will assign @steveklabnik instead
184 of a random person. This is entirely optional.
186 After someone has reviewed your pull request, they will leave an annotation
187 on the pull request with an `r+`. It will look something like this:
191 This tells @bors, our lovable integration bot, that your pull request has
192 been approved. The PR then enters the [merge queue][merge-queue], where @bors
193 will run all the tests on every platform we support. If it all works out,
194 @bors will merge your code into `master` and close the pull request.
196 [merge-queue]: http://buildbot.rust-lang.org/homu/queue/rust
198 Speaking of tests, Rust has a comprehensive test suite. More information about
200 [here](https://github.com/rust-lang/rust-wiki-backup/blob/master/Note-testsuite.md).
202 ## Writing Documentation
204 Documentation improvements are very welcome. The source of `doc.rust-lang.org`
205 is located in `src/doc` in the tree, and standard API documentation is generated
206 from the source code itself.
208 Documentation pull requests function in the same way as other pull requests,
209 though you may see a slightly different form of `r+`:
211 @bors: r+ 38fe8d2 rollup
213 That additional `rollup` tells @bors that this change is eligible for a 'rollup'.
214 To save @bors some work, and to get small changes through more quickly, when
215 @bors attempts to merge a commit that's rollup-eligible, it will also merge
216 the other rollup-eligible patches too, and they'll get tested and merged at
219 To find documentation-related issues, sort by the [A-docs label][adocs].
221 [adocs]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AA-docs
223 In many cases, you don't need a full `make doc`. You can use `rustdoc` directly
224 to check small fixes. For example, `rustdoc src/doc/reference.md` will render
225 reference to `doc/reference.html`. The CSS might be messed up, but you can
226 verify that HTML is right.
230 Sometimes, an issue will stay open, even though the bug has been fixed. And
231 sometimes, the original bug may go stale because something has changed in the
234 It can be helpful to go through older bug reports and make sure that they are
235 still valid. Load up an older issue, double check that it's still true, and
236 leave a comment letting us know if it is or is not. The [least recently
237 updated sort][lru] is good for finding issues like this.
239 Contributors with sufficient permissions on the Rust repo can help by adding
240 labels to triage issues:
242 * Yellow, **A**-prefixed labels state which **area** of the project an issue
245 * Magenta, **B**-prefixed labels identify bugs which are **blockers**.
247 * Green, **E**-prefixed labels explain the level of **experience** necessary
250 * Red, **I**-prefixed labels indicate the **importance** of the issue. The
251 [I-nominated][inom] label indicates that an issue has been nominated for
252 prioritizing at the next triage meeting.
254 * Orange, **P**-prefixed labels indicate a bug's **priority**. These labels
255 are only assigned during triage meetings, and replace the [I-nominated][inom]
258 * Blue, **T**-prefixed bugs denote which **team** the issue belongs to.
260 * Dark blue, **beta-** labels track changes which need to be backported into
263 * The purple **metabug** label marks lists of bugs collected by other
266 If you're looking for somewhere to start, check out the [E-easy][eeasy] tag.
268 [inom]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AI-nominated
269 [eeasy]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AE-easy
270 [lru]: https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-asc
272 ## Out-of-tree Contributions
274 There are a number of other ways to contribute to Rust that don't deal with
277 Answer questions in [#rust][pound-rust], or on [users.rust-lang.org][users],
278 or on [StackOverflow][so].
280 Participate in the [RFC process](https://github.com/rust-lang/rfcs).
282 Find a [requested community library][community-library], build it, and publish
283 it to [Crates.io](http://crates.io). Easier said than done, but very, very
286 [pound-rust]: http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust
287 [users]: https://users.rust-lang.org/
288 [so]: http://stackoverflow.com/questions/tagged/rust
289 [community-library]: https://github.com/rust-lang/rfcs/labels/A-community-library
291 ## Helpful Links and Information
293 For people new to Rust, and just starting to contribute, or even for
294 more seasoned developers, some useful places to look for information
297 * The [Rust Internals forum][rif], a place to ask questions and
298 discuss Rust's internals
299 * The [generated documentation for rust's compiler][gdfrustc]
300 * The [rust reference][rr], even though it doesn't specifically talk about Rust's internals, it's a great resource nonetheless
301 * Although out of date, [Tom Lee's great blog article][tlgba] is very helpful
302 * [rustaceans.org][ro] is helpful, but mostly dedicated to IRC
303 * The [Rust Compiler Testing Docs][rctd]
304 * For @bors, [this cheat sheet][cheatsheet] is helpful (Remember to replace `@homu` with `@bors` in the commands that you use.)
305 * **Google!** ([search only in Rust Documentation][gsearchdocs] to find types, traits, etc. quickly)
306 * Don't be afraid to ask! The Rust community is friendly and helpful.
308 [gdfrustc]: http://manishearth.github.io/rust-internals-docs/rustc/
309 [gsearchdocs]: https://www.google.com/search?q=site:doc.rust-lang.org+your+query+here
310 [rif]: http://internals.rust-lang.org
311 [rr]: https://doc.rust-lang.org/book/README.html
312 [tlgba]: http://tomlee.co/2014/04/a-more-detailed-tour-of-the-rust-compiler/
313 [ro]: http://www.rustaceans.org/
314 [rctd]: ./COMPILER_TESTS.md
315 [cheatsheet]: http://buildbot.rust-lang.org/homu/