* [Getting started](#getting-started)
* [Finding something to fix/improve](#finding-something-to-fiximprove)
* [Writing code](#writing-code)
- * [Author lint](#author-lint)
- * [Documentation](#documentation)
- * [Running test suite](#running-test-suite)
- * [Testing manually](#testing-manually)
- * [How Clippy works](#how-clippy-works)
- * [Fixing nightly build failures](#fixing-build-failures-caused-by-rust)
+* [How Clippy works](#how-clippy-works)
+* [Fixing nightly build failures](#fixing-build-failures-caused-by-rust)
+* [Issue and PR Triage](#issue-and-pr-triage)
+* [Bors and Homu](#bors-and-homu)
* [Contributions](#contributions)
## Getting started
All issues on Clippy are mentored, if you want help with a bug just ask @Manishearth, @llogiq, @mcarton or @oli-obk.
-Some issues are easier than others. The [`good first issue`](https://github.com/rust-lang-nursery/rust-clippy/labels/good%20first%20issue)
+Some issues are easier than others. The [`good first issue`](https://github.com/rust-lang/rust-clippy/labels/good%20first%20issue)
label can be used to find the easy issues. If you want to work on an issue, please leave a comment
so that we can assign it to you!
-Issues marked [`T-AST`](https://github.com/rust-lang-nursery/rust-clippy/labels/T-AST) involve simple
+There are also some abandoned PRs, marked with
+[`S-inactive-closed`](https://github.com/rust-lang/rust-clippy/pulls?q=is%3Aclosed+label%3AS-inactive-closed).
+Pretty often these PRs are nearly completed and just need some extra steps
+(formatting, addressing review comments, ...) to be merged. If you want to
+complete such a PR, please leave a comment in the PR and open a new one based
+on it.
+
+Issues marked [`T-AST`](https://github.com/rust-lang/rust-clippy/labels/T-AST) involve simple
matching of the syntax tree structure, and are generally easier than
-[`T-middle`](https://github.com/rust-lang-nursery/rust-clippy/labels/T-middle) issues, which involve types
+[`T-middle`](https://github.com/rust-lang/rust-clippy/labels/T-middle) issues, which involve types
and resolved paths.
-[`T-AST`](https://github.com/rust-lang-nursery/rust-clippy/labels/T-AST) issues will generally need you to match against a predefined syntax structure. To figure out
+[`T-AST`](https://github.com/rust-lang/rust-clippy/labels/T-AST) issues will generally need you to match against a predefined syntax structure. To figure out
how this syntax structure is encoded in the AST, it is recommended to run `rustc -Z ast-json` on an
example of the structure and compare with the
[nodes in the AST docs](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ast). Usually
the lint will end up to be a nested series of matches and ifs,
-[like so](https://github.com/rust-lang-nursery/rust-clippy/blob/de5ccdfab68a5e37689f3c950ed1532ba9d652a0/src/misc.rs#L34).
+[like so](https://github.com/rust-lang/rust-clippy/blob/de5ccdfab68a5e37689f3c950ed1532ba9d652a0/src/misc.rs#L34).
-[`E-medium`](https://github.com/rust-lang-nursery/rust-clippy/labels/E-medium) issues are generally
+[`E-medium`](https://github.com/rust-lang/rust-clippy/labels/E-medium) issues are generally
pretty easy too, though it's recommended you work on an E-easy issue first. They are mostly classified
as `E-medium`, since they might be somewhat involved code wise, but not difficult per-se.
-[`T-middle`](https://github.com/rust-lang-nursery/rust-clippy/labels/T-middle) issues can
+[`T-middle`](https://github.com/rust-lang/rust-clippy/labels/T-middle) issues can
be more involved and require verifying types. The
[`ty`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty) module contains a
lot of methods that are useful, though one of the most useful would be `expr_ty` (gives the type of
## Writing code
-Compiling Clippy from scratch can take almost a minute or more depending on your machine.
-However, since Rust 1.24.0 incremental compilation is enabled by default and compile times for small changes should be quick.
-
-[Llogiq's blog post on lints](https://llogiq.github.io/2015/06/04/workflows.html) is a nice primer
-to lint-writing, though it does get into advanced stuff. Most lints consist of an implementation of
-`LintPass` with one or more of its default methods overridden. See the existing lints for examples
-of this.
-
-
-### Author lint
-
-There is also the internal `author` lint to generate Clippy code that detects the offending pattern. It does not work for all of the Rust syntax, but can give a good starting point.
-
-First, create a new UI test file in the `tests/ui/` directory with the pattern you want to match:
-
-```rust
-// ./tests/ui/my_lint.rs
-fn main() {
- #[clippy::author]
- let arr: [i32; 1] = [7]; // Replace line with the code you want to match
-}
-```
-
-Now you run `TESTNAME=ui/my_lint cargo test --test compile-test` to produce
-a `.stdout` file with the generated code:
-
-```rust
-// ./tests/ui/my_lint.stdout
-
-if_chain! {
- if let ExprKind::Array(ref elements) = stmt.node;
- if elements.len() == 1;
- if let ExprKind::Lit(ref lit) = elements[0].node;
- if let LitKind::Int(7, _) = lit.node;
- then {
- // report your lint here
- }
-}
-```
-
-If the command was executed successfully, you can copy the code over to where you are implementing your lint.
-
-### Documentation
-
-Please document your lint with a doc comment akin to the following:
-
-```rust
-/// **What it does:** Checks for ... (describe what the lint matches).
-///
-/// **Why is this bad?** Supply the reason for linting the code.
-///
-/// **Known problems:** None. (Or describe where it could go wrong.)
-///
-/// **Example:**
-///
-/// ```rust
-/// // Bad
-/// Insert a short example of code that triggers the lint
-///
-/// // Good
-/// Insert a short example of improved code that doesn't trigger the lint
-/// ```
-```
-
-Once your lint is merged it will show up in the [lint list](https://rust-lang-nursery.github.io/rust-clippy/master/index.html)
-
-### Running test suite
-
-Use `cargo test` to run the whole testsuite.
-
-If you don't want to wait for all tests to finish, you can also execute a single test file by using `TESTNAME` to specify the test to run:
-
-```bash
-TESTNAME=ui/empty_line_after_outer_attr cargo test --test compile-test
-```
-
-Clippy uses UI tests. UI tests check that the output of the compiler is exactly as expected.
-Of course there's little sense in writing the output yourself or copying it around.
-Therefore you should use `tests/ui/update-all-references.sh` (after running
-`cargo test`) and check whether the output looks as you expect with `git diff`. Commit all
-`*.stderr` files, too.
-
-### Testing manually
+Have a look at the [docs for writing lints](doc/adding_lints.md) for more details. [Llogiq's blog post on lints](https://llogiq.github.io/2015/06/04/workflows.html) is also a nice primer
+to lint-writing, though it does get into advanced stuff and may be a bit
+outdated.
-Manually testing against an example file is useful if you have added some
-`println!`s and test suite output becomes unreadable. To try Clippy with your
-local modifications, run `cargo run --bin clippy-driver -- -L ./target/debug input.rs` from the
-working copy root.
+If you want to add a new lint or change existing ones apart from bugfixing, it's
+also a good idea to give the [stability guarantees][rfc_stability] and
+[lint categories][rfc_lint_cats] sections of the [Clippy 1.0 RFC][clippy_rfc] a
+quick read.
-### How Clippy works
+## How Clippy works
Clippy is a [rustc compiler plugin][compiler_plugin]. The main entry point is at [`src/lib.rs`][main_entry]. In there, the lint registration is delegated to the [`clippy_lints`][lint_crate] crate.
The [`rustc_plugin::PluginRegistry`][plugin_registry] provides two methods to register lints: [register_early_lint_pass][reg_early_lint_pass] and [register_late_lint_pass][reg_late_lint_pass].
Both take an object that implements an [`EarlyLintPass`][early_lint_pass] or [`LateLintPass`][late_lint_pass] respectively. This is done in every single lint.
-It's worth noting that the majority of `clippy_lints/src/lib.rs` is autogenerated by `util/update_lints.py` and you don't have to add anything by hand. When you are writing your own lint, you can use that script to save you some time.
+It's worth noting that the majority of `clippy_lints/src/lib.rs` is autogenerated by `util/dev update_lints` and you don't have to add anything by hand. When you are writing your own lint, you can use that script to save you some time.
```rust
// ./clippy_lints/src/else_if_without_else.rs
That's why the `else_if_without_else` example uses the `register_early_lint_pass` function. Because the [actual lint logic][else_if_without_else] does not depend on any type information.
-### Fixing build failures caused by Rust
+## Fixing build failures caused by Rust
-Clippy will sometimes break because it still depends on unstable internal Rust features. Most of the times we have to adapt to the changes and only very rarely there's an actual bug in Rust. Fixing build failures caused by Rust updates, can be a good way to learn about Rust internals.
+Clippy will sometimes fail to build from source because building it depends on unstable internal Rust features. Most of the times we have to adapt to the changes and only very rarely there's an actual bug in Rust. Fixing build failures caused by Rust updates, can be a good way to learn about Rust internals.
In order to find out why Clippy does not work properly with a new Rust commit, you can use the [rust-toolstate commit history][toolstate_commit_history].
You will then have to look for the last commit that contains `test-pass -> build-fail` or `test-pass` -> `test-fail` for the `clippy-driver` component. [Here][toolstate_commit] is an example.
cargo test
```
+## Issue and PR triage
+
+Clippy is following the [Rust triage procedure][triage] for issues and pull
+requests.
+
+However, we are a smaller project with all contributors being volunteers
+currently. Between writing new lints, fixing issues, reviewing pull requests and
+responding to issues there may not always be enough time to stay on top of it
+all.
+
+Our highest priority is fixing [crashes][l-crash] and [bugs][l-bug]. We don't
+want Clippy to crash on your code and we want it to be as reliable as the
+suggestions from Rust compiler errors.
+
+## Bors and Homu
+
+We use a bot powered by [Homu][homu] to help automate testing and landing of pull
+requests in Clippy. The bot's username is @bors.
+
+You can find the Clippy bors queue [here][homu_queue].
+
+If you have @bors permissions, you can find an overview of the available
+commands [here][homu_instructions].
+
+
## Contributions
Contributions to Clippy should be made in the form of GitHub pull requests. Each pull request will
be reviewed by a core contributor (someone with permission to land patches) and either landed in the
main tree or given feedback for changes that would be required.
-All code in this repository is under the [Mozilla Public License, 2.0](https://www.mozilla.org/MPL/2.0/)
+All code in this repository is under the [Apache-2.0](http://www.apache.org/licenses/LICENSE-2.0>)
+or the [MIT](http://opensource.org/licenses/MIT) license.
<!-- adapted from https://github.com/servo/servo/blob/master/CONTRIBUTING.md -->
-[main_entry]: https://github.com/rust-lang-nursery/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/src/lib.rs#L14
-[lint_crate]: https://github.com/rust-lang-nursery/rust-clippy/tree/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src
-[lint_crate_entry]: https://github.com/rust-lang-nursery/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src/lib.rs
-[else_if_without_else]: https://github.com/rust-lang-nursery/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src/else_if_without_else.rs
+[main_entry]: https://github.com/rust-lang/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/src/lib.rs#L14
+[lint_crate]: https://github.com/rust-lang/rust-clippy/tree/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src
+[lint_crate_entry]: https://github.com/rust-lang/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src/lib.rs
+[else_if_without_else]: https://github.com/rust-lang/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src/else_if_without_else.rs
[compiler_plugin]: https://doc.rust-lang.org/unstable-book/language-features/plugin.html#lint-plugins
[plugin_registry]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin/registry/struct.Registry.html
[reg_early_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin/registry/struct.Registry.html#method.register_early_lint_pass
[toolstate_commit]: https://github.com/rust-lang-nursery/rust-toolstate/commit/6ce0459f6bfa7c528ae1886492a3e0b5ef0ee547
[rtim]: https://github.com/kennytm/rustup-toolchain-install-master
[rustup_component_history]: https://mexus.github.io/rustup-components-history
+[clippy_rfc]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md
+[rfc_stability]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md#stability-guarantees
+[rfc_lint_cats]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md#lint-audit-and-categories
+[triage]: https://forge.rust-lang.org/triage-procedure.html
+[l-crash]: https://github.com/rust-lang/rust-clippy/labels/L-crash%20%3Aboom%3A
+[l-bug]: https://github.com/rust-lang/rust-clippy/labels/L-bug%20%3Abeetle%3A
+[homu]: https://github.com/servo/homu
+[homu_instructions]: https://buildbot2.rust-lang.org/homu/
+[homu_queue]: https://buildbot2.rust-lang.org/homu/queue/clippy
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