-# rustfmt [](https://travis-ci.org/rust-lang-nursery/rustfmt)
+# rustfmt [](https://travis-ci.org/rust-lang-nursery/rustfmt) [](https://ci.appveyor.com/project/nrc/rustfmt) [](https://crates.io/crates/rustfmt-nightly) [](https://travis-ci.org/davidalber/rustfmt-travis)
A tool for formatting Rust code according to style guidelines.
If you'd like to help out (and you should, it's a fun project!), see
-[Contributing.md](Contributing.md).
+[Contributing.md](Contributing.md) and our [Code of
+Conduct](CODE_OF_CONDUCT.md).
+
+You can use rustfmt in Travis CI builds. We provide a minimal Travis CI
+configuration (see [here](#checking-style-on-a-ci-server)) and verify its status
+using another repository. The status of that repository's build is reported by
+the "travis example" badge above.
## Quick start
+You can run `rustfmt` with Rust 1.24 and above.
+
To install:
```
-cargo install rustfmt
+rustup component add rustfmt-preview
```
to run on a cargo project in the current working directory:
cargo fmt
```
-## Installation
+For the latest and greatest `rustfmt` (nightly required):
+```
+rustup component add rustfmt-preview --toolchain nightly
+```
+To run:
+```
+cargo +nightly fmt
+```
-> **Note:** this method currently requires you to be running cargo 0.6.0 or
-> newer.
+To format code that requires edition 2018, create a `rustfmt.toml` [configuration](#configuring-rustfmt) file containing:
-```
-cargo install rustfmt
+```toml
+edition = "2018"
```
-or if you're using [`multirust`](https://github.com/brson/multirust)
+## Limitations
+
+Rustfmt tries to work on as much Rust code as possible, sometimes, the code
+doesn't even need to compile! As we approach a 1.0 release we are also looking
+to limit areas of instability; in particular, post-1.0, the formatting of most
+code should not change as Rustfmt improves. However, there are some things that
+Rustfmt can't do or can't do well (and thus where formatting might change
+significantly, even post-1.0). We would like to reduce the list of limitations
+over time.
+
+The following list enumerates areas where Rustfmt does not work or where the
+stability guarantees do not apply (we don't make a distinction between the two
+because in the future Rustfmt might work on code where it currently does not):
+
+* a program where any part of the program does not parse (parsing is an early
+ stage of compilation and in Rust includes macro expansion).
+* Macro declarations and uses (current status: some macro declarations and uses
+ are formatted).
+* Comments, including any AST node with a comment 'inside' (Rustfmt does not
+ currently attempt to format comments, it does format code with comments inside, but that formatting may change in the future).
+* Rust code in code blocks in comments.
+* Any fragment of a program (i.e., stability guarantees only apply to whole
+ programs, even where fragments of a program can be formatted today).
+* Code containing non-ascii unicode characters (we believe Rustfmt mostly works
+ here, but do not have the test coverage or experience to be 100% sure).
+* Bugs in Rustfmt (like any software, Rustfmt has bugs, we do not consider bug
+ fixes to break our stability guarantees).
+
+
+## Installation
```
-multirust run nightly cargo install rustfmt
+rustup component add rustfmt-preview
```
-Usually cargo-fmt, which enables usage of Cargo subcommand `cargo fmt`, is
-installed alongside rustfmt. To only install rustfmt run
+## Installing from source
+
+To install from source (nightly required), first checkout to the tag or branch you want to install, then issue
```
-cargo install --no-default-features rustfmt
+cargo install --path .
```
+This will install `rustfmt` in your `~/.cargo/bin`. Make sure to add `~/.cargo/bin` directory to
+your PATH variable.
+
+
## Running
You can run Rustfmt by just typing `rustfmt filename` if you used `cargo
read data from stdin. Alternatively, you can use `cargo fmt` to format all
binary and library targets of your crate.
-You'll probably want to specify the write mode. Currently, there are modes for
-diff, replace, overwrite, display, coverage, and checkstyle.
+You can run `rustfmt --help` for information about argument.
-* `replace` Is the default and overwrites the original files after creating backups of the files.
-* `overwrite` Overwrites the original files _without_ creating backups.
-* `display` Will print the formatted files to stdout.
-* `diff` Will print a diff between the original files and formatted files to stdout.
-* `checkstyle` Will output the lines that need to be corrected as a checkstyle XML file,
- that can be used by tools like Jenkins.
+When running with `--check`, Rustfmt will exit with `0` if Rustfmt would not
+make any formatting changes to the input, and `1` if Rustfmt would make changes.
+In other modes, Rustfmt will exit with `1` if there was some error during
+formatting (for example a parsing or internal error) and `0` if formatting
+completed without error (whether or not changes were made).
-The write mode can be set by passing the `--write-mode` flag on
-the command line. For example `rustfmt --write-mode=display src/filename.rs`
-`cargo fmt` uses `--write-mode=replace` by default.
-If `rustfmt` successfully reformatted the code it will exit with `0` exit
-status. Exit status `1` signals some unexpected error, like an unknown option or
-a failure to read a file. Exit status `2` is returned if there are syntax errors
-in the input files. `rustfmt` can't format syntatically invalid code. Finally,
-exit status `3` is returned if there are some issues which can't be resolved
-automatically. For example, if you have a very long comment line `rustfmt`
-doesn't split it. Instead it prints a warning and exits with `3`.
+## Running Rustfmt from your editor
-You can run `rustfmt --help` for more information.
+* [Vim](https://github.com/rust-lang/rust.vim#formatting-with-rustfmt)
+* [Emacs](https://github.com/rust-lang/rust-mode)
+* [Sublime Text 3](https://packagecontrol.io/packages/RustFmt)
+* [Atom](atom.md)
+* Visual Studio Code using [vscode-rust](https://github.com/editor-rs/vscode-rust), [vsc-rustfmt](https://github.com/Connorcpu/vsc-rustfmt) or [rls_vscode](https://github.com/jonathandturner/rls_vscode) through RLS.
-## Running Rustfmt from your editor
+## Checking style on a CI server
-* [Vim](http://johannh.me/blog/rustfmt-vim.html)
-* [Emacs](https://github.com/fbergroth/emacs-rustfmt)
-* [Sublime Text 3](https://packagecontrol.io/packages/BeautifyRust)
-* [Atom](atom.md)
-* Visual Studio Code using [RustyCode](https://github.com/saviorisdead/RustyCode) or [vsc-rustfmt](https://github.com/Connorcpu/vsc-rustfmt)
+To keep your code base consistently formatted, it can be helpful to fail the CI build
+when a pull request contains unformatted code. Using `--check` instructs
+rustfmt to exit with an error code if the input is not formatted correctly.
+It will also print any found differences. (Older versions of Rustfmt don't
+support `--check`, use `--write-mode diff`).
+
+A minimal Travis setup could look like this (requires Rust 1.24.0 or greater):
+
+```yaml
+language: rust
+before_script:
+- rustup component add rustfmt-preview
+script:
+- cargo fmt --all -- --check
+- cargo build
+- cargo test
+```
+
+See [this blog post](https://medium.com/@ag_dubs/enforcing-style-in-ci-for-rust-projects-18f6b09ec69d)
+for more info.
## How to build and test
## Configuring Rustfmt
Rustfmt is designed to be very configurable. You can create a TOML file called
-rustfmt.toml, place it in the project directory and it will apply the options
-in that file. See `rustfmt --config-help` for the options which are available,
-or if you prefer to see source code, [src/config.rs](src/config.rs).
+`rustfmt.toml` or `.rustfmt.toml`, place it in the project or any other parent
+directory and it will apply the options in that file. See `rustfmt
+--help=config` for the options which are available, or if you prefer to see
+visual style previews, [Configurations.md](Configurations.md).
-By default, Rustfmt uses a style which (mostly) conforms to the
-[Rust style guidelines](https://github.com/rust-lang/rust/tree/master/src/doc/style).
-There are many details which the style guidelines do not cover, and in these
-cases we try to adhere to a style similar to that used in the
-[Rust repo](https://github.com/rust-lang/rust). Once Rustfmt is more complete, and
-able to re-format large repositories like Rust, we intend to go through the Rust
-RFC process to nail down the default style in detail.
+By default, Rustfmt uses a style which conforms to the [Rust style guide][style
+guide] that has been formalized through the [style RFC
+process][fmt rfcs].
-If there are styling choices you don't agree with, we are usually happy to add
-options covering different styles. File an issue, or even better, submit a PR.
+Configuration options are either stable or unstable. Stable options can always
+be used, while unstable ones are only available on a nightly toolchain, and opt-in.
+See [Configurations.md](Configurations.md) for details.
-## Gotchas
+## Tips
* For things you do not want rustfmt to mangle, use one of
```rust
- #[rustfmt_skip] // requires nightly and #![feature(custom_attribute)] in crate root
+ #[rustfmt::skip] // requires nightly Rust and #![feature(tool_attributes)] in crate root
#[cfg_attr(rustfmt, rustfmt_skip)] // works in stable
```
-* When you run rustfmt, place a file named rustfmt.toml in target file
- directory or its parents to override the default settings of rustfmt.
+* When you run rustfmt, place a file named `rustfmt.toml` or `.rustfmt.toml` in
+ target file directory or its parents to override the default settings of
+ rustfmt. You can generate a file containing the default configuration with
+ `rustfmt --print-config default rustfmt.toml` and customize as needed.
* After successful compilation, a `rustfmt` executable can be found in the
target directory.
+* If you're having issues compiling Rustfmt (or compile errors when trying to
+ install), make sure you have the most recent version of Rust installed.
+
+* You can change the way rustfmt emits the changes with the --emit flag:
+
+ Example:
+
+ ```
+ cargo fmt -- --emit files
+ ```
+
+ Options:
+
+ | Flag |Description| Nightly Only |
+ |:---:|:---:|:---:|
+ | files | overwrites output to files | No |
+ | stdout | writes output to stdout | No |
+ | coverage | displays how much of the input file was processed | Yes |
+ | checkstyle | emits in a checkstyle format | Yes |
+
+## License
+
+Rustfmt is distributed under the terms of both the MIT license and the
+Apache License (Version 2.0).
+
+See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT) for details.
+
+[rust]: https://github.com/rust-lang/rust
+[fmt rfcs]: https://github.com/rust-lang-nursery/fmt-rfcs
+[style guide]: https://github.com/rust-lang-nursery/fmt-rfcs/blob/master/guide/guide.md
projects / rust.git / blobdiff