mirror of
https://github.com/rust-lang/rust
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415 lines
16 KiB
Markdown
# Contributing to Rust
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Thank you for your interest in contributing to Rust! There are many ways to
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contribute, and we appreciate all of them. This document is a bit long, so here's
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links to the major sections:
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* [Feature Requests](#feature-requests)
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* [Bug Reports](#bug-reports)
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* [The Build System](#the-build-system)
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* [Pull Requests](#pull-requests)
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* [Writing Documentation](#writing-documentation)
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* [Issue Triage](#issue-triage)
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* [Out-of-tree Contributions](#out-of-tree-contributions)
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* [Helpful Links and Information](#helpful-links-and-information)
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If you have questions, please make a post on [internals.rust-lang.org][internals] or
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hop on [#rust-internals][pound-rust-internals].
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As a reminder, all contributors are expected to follow our [Code of Conduct][coc].
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[pound-rust-internals]: http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-internals
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[internals]: https://internals.rust-lang.org
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[coc]: https://www.rust-lang.org/conduct.html
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## Feature Requests
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To request a change to the way that the Rust language works, please open an
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issue in the [RFCs repository](https://github.com/rust-lang/rfcs/issues/new)
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rather than this one. New features and other significant language changes
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must go through the RFC process.
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## Bug Reports
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While bugs are unfortunate, they're a reality in software. We can't fix what we
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don't know about, so please report liberally. If you're not sure if something
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is a bug or not, feel free to file a bug anyway.
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**If you believe reporting your bug publicly represents a security risk to Rust users,
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please follow our [instructions for reporting security vulnerabilities](https://www.rust-lang.org/security.html)**.
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If you have the chance, before reporting a bug, please [search existing
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issues](https://github.com/rust-lang/rust/search?q=&type=Issues&utf8=%E2%9C%93),
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as it's possible that someone else has already reported your error. This doesn't
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always work, and sometimes it's hard to know what to search for, so consider this
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extra credit. We won't mind if you accidentally file a duplicate report.
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Opening an issue is as easy as following [this
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link](https://github.com/rust-lang/rust/issues/new) and filling out the fields.
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Here's a template that you can use to file a bug, though it's not necessary to
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use it exactly:
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<short summary of the bug>
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I tried this code:
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<code sample that causes the bug>
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I expected to see this happen: <explanation>
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Instead, this happened: <explanation>
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## Meta
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`rustc --version --verbose`:
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Backtrace:
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All three components are important: what you did, what you expected, what
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happened instead. Please include the output of `rustc --version --verbose`,
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which includes important information about what platform you're on, what
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version of Rust you're using, etc.
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Sometimes, a backtrace is helpful, and so including that is nice. To get
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a backtrace, set the `RUST_BACKTRACE` environment variable to a value
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other than `0`. The easiest way
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to do this is to invoke `rustc` like this:
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```bash
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$ RUST_BACKTRACE=1 rustc ...
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```
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## The Build System
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Rust's build system allows you to bootstrap the compiler, run tests &
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benchmarks, generate documentation, install a fresh build of Rust, and more.
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It's your best friend when working on Rust, allowing you to compile & test
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your contributions before submission.
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The build system lives in [the `src/bootstrap` directory][bootstrap] in the
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project root. Our build system is itself written in Rust and is based on Cargo
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to actually build all the compiler's crates. If you have questions on the build
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system internals, try asking in [`#rust-internals`][pound-rust-internals].
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[bootstrap]: https://github.com/rust-lang/rust/tree/master/src/bootstrap/
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### Configuration
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Before you can start building the compiler you need to configure the build for
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your system. In most cases, that will just mean using the defaults provided
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for Rust.
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To change configuration, you must copy the file `src/bootstrap/config.toml.example`
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to `config.toml` in the directory from which you will be running the build, and
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change the settings provided.
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There are large number of options provided in this config file that will alter the
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configuration used in the build process. Some options to note:
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#### `[llvm]`:
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- `ccache = true` - Use ccache when building llvm
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#### `[build]`:
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- `compiler-docs = true` - Build compiler documentation
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#### `[rust]`:
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- `debuginfo = true` - Build a compiler with debuginfo
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- `optimize = false` - Disable optimizations to speed up compilation of stage1 rust
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For more options, the `config.toml` file contains commented out defaults, with
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descriptions of what each option will do.
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Note: Previously the `./configure` script was used to configure this
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project. It can still be used, but it's recommended to use a `config.toml`
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file. If you still have a `config.mk` file in your directory - from
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`./configure` - you may need to delete it for `config.toml` to work.
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### Building
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The build system uses the `x.py` script to control the build process. This script
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is used to build, test, and document various parts of the compiler. You can
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execute it as:
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```sh
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python x.py build
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```
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On some systems you can also use the shorter version:
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```sh
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./x.py build
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```
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To learn more about the driver and top-level targets, you can execute:
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```sh
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python x.py --help
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```
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The general format for the driver script is:
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```sh
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python x.py <command> [<directory>]
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```
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Some example commands are `build`, `test`, and `doc`. These will build, test,
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and document the specified directory. The second argument, `<directory>`, is
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optional and defaults to working over the entire compiler. If specified,
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however, only that specific directory will be built. For example:
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```sh
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# build the entire compiler
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python x.py build
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# build all documentation
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python x.py doc
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# run all test suites
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python x.py test
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# build only the standard library
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python x.py build src/libstd
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# test only one particular test suite
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python x.py test src/test/rustdoc
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# build only the stage0 libcore library
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python x.py build src/libcore --stage 0
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```
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You can explore the build system throught the various `--help` pages for each
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subcommand. For example to learn more about a command you can run:
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```
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python x.py build --help
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```
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To learn about all possible rules you can execute, run:
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```
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python x.py build --help --verbose
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```
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Note: Previously `./configure` and `make` were used to build this project.
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They are still available, but `x.py` is the recommended build system.
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### Useful commands
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Some common invocations of `x.py` are:
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- `x.py build --help` - show the help message and explain the subcommand
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- `x.py build src/libtest --stage 1` - build up to (and including) the first
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stage. For most cases we don't need to build the stage2 compiler, so we can
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save time by not building it. The stage1 compiler is a fully functioning
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compiler and (probably) will be enough to determine if your change works as
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expected.
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- `x.py build src/rustc --stage 1` - This will build just rustc, without libstd.
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This is the fastest way to recompile after you changed only rustc source code.
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Note however that the resulting rustc binary won't have a stdlib to link
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against by default. You can build libstd once with `x.py build src/libstd`,
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but it is only guaranteed to work if recompiled, so if there are any issues
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recompile it.
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- `x.py test` - build the full compiler & run all tests (takes a while). This
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is what gets run by the continuous integration system against your pull
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request. You should run this before submitting to make sure your tests pass
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& everything builds in the correct manner.
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- `x.py test src/libstd --stage 1` - test the standard library without
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recompiling stage 2.
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- `x.py test src/test/run-pass --test-args TESTNAME` - Run a matching set of
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tests.
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- `TESTNAME` should be a substring of the tests to match against e.g. it could
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be the fully qualified test name, or just a part of it.
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`TESTNAME=collections::hash::map::test_map::test_capacity_not_less_than_len`
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or `TESTNAME=test_capacity_not_less_than_len`.
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- `x.py test src/test/run-pass --stage 1 --test-args <substring-of-test-name>` -
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Run a single rpass test with the stage1 compiler (this will be quicker than
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running the command above as we only build the stage1 compiler, not the entire
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thing). You can also leave off the directory argument to run all stage1 test
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types.
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- `x.py test src/libcore --stage 1` - Run stage1 tests in `libcore`.
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- `x.py test src/tools/tidy` - Check that the source code is in compliance with
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Rust's style guidelines. There is no official document describing Rust's full
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guidelines as of yet, but basic rules like 4 spaces for indentation and no
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more than 99 characters in a single line should be kept in mind when writing
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code.
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## Pull Requests
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Pull requests are the primary mechanism we use to change Rust. GitHub itself
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has some [great documentation][pull-requests] on using the Pull Request
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feature. We use the 'fork and pull' model described there.
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[pull-requests]: https://help.github.com/articles/using-pull-requests/
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Please make pull requests against the `master` branch.
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Compiling all of `./x.py test` can take a while. When testing your pull request,
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consider using one of the more specialized `./x.py` targets to cut down on the
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amount of time you have to wait. You need to have built the compiler at least
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once before running these will work, but that’s only one full build rather than
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one each time.
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$ python x.py test --stage 1
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is one such example, which builds just `rustc`, and then runs the tests. If
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you’re adding something to the standard library, try
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$ python x.py test src/libstd --stage 1
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Please make sure your pull request is in compliance with Rust's style
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guidelines by running
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$ python x.py test src/tools/tidy
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Make this check before every pull request (and every new commit in a pull
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request) ; you can add [git hooks](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks)
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before every push to make sure you never forget to make this check.
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All pull requests are reviewed by another person. We have a bot,
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@rust-highfive, that will automatically assign a random person to review your
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request.
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If you want to request that a specific person reviews your pull request,
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you can add an `r?` to the message. For example, Steve usually reviews
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documentation changes. So if you were to make a documentation change, add
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r? @steveklabnik
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to the end of the message, and @rust-highfive will assign @steveklabnik instead
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of a random person. This is entirely optional.
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After someone has reviewed your pull request, they will leave an annotation
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on the pull request with an `r+`. It will look something like this:
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@bors: r+ 38fe8d2
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This tells @bors, our lovable integration bot, that your pull request has
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been approved. The PR then enters the [merge queue][merge-queue], where @bors
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will run all the tests on every platform we support. If it all works out,
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@bors will merge your code into `master` and close the pull request.
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[merge-queue]: https://buildbot.rust-lang.org/homu/queue/rust
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Speaking of tests, Rust has a comprehensive test suite. More information about
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it can be found
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[here](https://github.com/rust-lang/rust-wiki-backup/blob/master/Note-testsuite.md).
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## Writing Documentation
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Documentation improvements are very welcome. The source of `doc.rust-lang.org`
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is located in `src/doc` in the tree, and standard API documentation is generated
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from the source code itself.
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Documentation pull requests function in the same way as other pull requests,
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though you may see a slightly different form of `r+`:
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@bors: r+ 38fe8d2 rollup
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That additional `rollup` tells @bors that this change is eligible for a 'rollup'.
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To save @bors some work, and to get small changes through more quickly, when
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@bors attempts to merge a commit that's rollup-eligible, it will also merge
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the other rollup-eligible patches too, and they'll get tested and merged at
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the same time.
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To find documentation-related issues, sort by the [T-doc label][tdoc].
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[tdoc]: https://github.com/rust-lang/rust/issues?q=is%3Aopen%20is%3Aissue%20label%3AT-doc
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You can find documentation style guidelines in [RFC 1574][rfc1574].
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[rfc1574]: https://github.com/rust-lang/rfcs/blob/master/text/1574-more-api-documentation-conventions.md#appendix-a-full-conventions-text
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In many cases, you don't need a full `./x.py doc`. You can use `rustdoc` directly
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to check small fixes. For example, `rustdoc src/doc/reference.md` will render
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reference to `doc/reference.html`. The CSS might be messed up, but you can
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verify that the HTML is right.
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## Issue Triage
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Sometimes, an issue will stay open, even though the bug has been fixed. And
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sometimes, the original bug may go stale because something has changed in the
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meantime.
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It can be helpful to go through older bug reports and make sure that they are
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still valid. Load up an older issue, double check that it's still true, and
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leave a comment letting us know if it is or is not. The [least recently
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updated sort][lru] is good for finding issues like this.
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Contributors with sufficient permissions on the Rust repo can help by adding
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labels to triage issues:
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* Yellow, **A**-prefixed labels state which **area** of the project an issue
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relates to.
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* Magenta, **B**-prefixed labels identify bugs which are **blockers**.
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* Green, **E**-prefixed labels explain the level of **experience** necessary
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to fix the issue.
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* Red, **I**-prefixed labels indicate the **importance** of the issue. The
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[I-nominated][inom] label indicates that an issue has been nominated for
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prioritizing at the next triage meeting.
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* Orange, **P**-prefixed labels indicate a bug's **priority**. These labels
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are only assigned during triage meetings, and replace the [I-nominated][inom]
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label.
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* Blue, **T**-prefixed bugs denote which **team** the issue belongs to.
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* Dark blue, **beta-** labels track changes which need to be backported into
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the beta branches.
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* The purple **metabug** label marks lists of bugs collected by other
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categories.
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If you're looking for somewhere to start, check out the [E-easy][eeasy] tag.
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[inom]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AI-nominated
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[eeasy]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AE-easy
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[lru]: https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-asc
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## Out-of-tree Contributions
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There are a number of other ways to contribute to Rust that don't deal with
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this repository.
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Answer questions in [#rust][pound-rust], or on [users.rust-lang.org][users],
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or on [StackOverflow][so].
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Participate in the [RFC process](https://github.com/rust-lang/rfcs).
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Find a [requested community library][community-library], build it, and publish
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it to [Crates.io](http://crates.io). Easier said than done, but very, very
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valuable!
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[pound-rust]: http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust
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[users]: https://users.rust-lang.org/
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[so]: http://stackoverflow.com/questions/tagged/rust
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[community-library]: https://github.com/rust-lang/rfcs/labels/A-community-library
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## Helpful Links and Information
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For people new to Rust, and just starting to contribute, or even for
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more seasoned developers, some useful places to look for information
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are:
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* The [Rust Internals forum][rif], a place to ask questions and
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discuss Rust's internals
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* The [generated documentation for rust's compiler][gdfrustc]
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* The [rust reference][rr], even though it doesn't specifically talk about Rust's internals, it's a great resource nonetheless
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* Although out of date, [Tom Lee's great blog article][tlgba] is very helpful
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* [rustaceans.org][ro] is helpful, but mostly dedicated to IRC
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* The [Rust Compiler Testing Docs][rctd]
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* For @bors, [this cheat sheet][cheatsheet] is helpful (Remember to replace `@homu` with `@bors` in the commands that you use.)
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* **Google!** ([search only in Rust Documentation][gsearchdocs] to find types, traits, etc. quickly)
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* Don't be afraid to ask! The Rust community is friendly and helpful.
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[gdfrustc]: http://manishearth.github.io/rust-internals-docs/rustc/
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[gsearchdocs]: https://www.google.com/search?q=site:doc.rust-lang.org+your+query+here
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[rif]: http://internals.rust-lang.org
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[rr]: https://doc.rust-lang.org/book/README.html
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[tlgba]: http://tomlee.co/2014/04/a-more-detailed-tour-of-the-rust-compiler/
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[ro]: http://www.rustaceans.org/
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[rctd]: ./src/test/COMPILER_TESTS.md
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[cheatsheet]: https://buildbot.rust-lang.org/homu/
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