250 lines
8.9 KiB
Markdown
250 lines
8.9 KiB
Markdown
# rustfmt [](https://travis-ci.org/rust-lang-nursery/rustfmt) [](https://ci.appveyor.com/api/projects/status/github/rust-lang-nursery/rustfmt)
|
|
|
|
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).
|
|
|
|
We are changing the default style used by rustfmt. There is an ongoing [RFC
|
|
process][fmt rfcs]. The last version using the old style was 0.8.6. From 0.9
|
|
onwards, the RFC style is the default. If you want the old style back, you can
|
|
use [legacy-rustfmt.toml](legacy-rustfmt.toml) as your rustfmt.toml.
|
|
|
|
The current `master` branch uses libsyntax (part of the compiler). It is
|
|
published as `rustfmt-nightly`. The `syntex` branch uses Syntex instead of
|
|
libsyntax, it is published (for now) as `rustfmt`. Most development happens on
|
|
the `master` branch, however, this only supports nightly toolchains. If you use
|
|
stable or beta Rust toolchains, you must use the Syntex version (which is likely
|
|
to be a bit out of date). Version 0.1 of rustfmt-nightly is forked from version
|
|
0.9 of the syntex branch.
|
|
|
|
|
|
## Quick start
|
|
|
|
You must be using the latest nightly compiler toolchain.
|
|
|
|
To install:
|
|
|
|
```
|
|
cargo install rustfmt-nightly
|
|
```
|
|
|
|
to run on a cargo project in the current working directory:
|
|
|
|
```
|
|
cargo fmt
|
|
```
|
|
|
|
## Installation
|
|
|
|
```
|
|
cargo install rustfmt-nightly
|
|
```
|
|
|
|
or if you're using [Rustup](https://www.rustup.rs/)
|
|
|
|
```
|
|
rustup update
|
|
rustup run nightly cargo install rustfmt-nightly
|
|
```
|
|
|
|
If you don't have a nightly toolchain, you can add it using rustup:
|
|
|
|
```
|
|
rustup install nightly
|
|
```
|
|
|
|
You can make the nightly toolchain the default by running:
|
|
|
|
```
|
|
rustup default nightly
|
|
```
|
|
|
|
If you choose not to do that you'll have to run rustfmt using `rustup run ...`
|
|
or by adding `+nightly` to the cargo invocation.
|
|
|
|
Usually cargo-fmt, which enables usage of Cargo subcommand `cargo fmt`, is
|
|
installed alongside rustfmt. To only install rustfmt run
|
|
|
|
```
|
|
cargo install --no-default-features rustfmt-nightly
|
|
```
|
|
## Installing from source
|
|
|
|
To install from source, first checkout to the tag or branch you want to install, then issue
|
|
```
|
|
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
|
|
install`. This runs rustfmt on the given file, if the file includes out of line
|
|
modules, then we reformat those too. So to run on a whole module or crate, you
|
|
just need to run on the root file (usually mod.rs or lib.rs). Rustfmt can also
|
|
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`, `checkstyle`, and `plain`.
|
|
|
|
* `overwrite` Is the default and overwrites the original files _without_ creating backups.
|
|
* `replace` Overwrites the original files after creating backups of the files.
|
|
* `display` Will print the formatted files to stdout.
|
|
* `plain` Also writes to stdout, but with no metadata.
|
|
* `diff` Will print a diff between the original files and formatted files to stdout.
|
|
Will also exit with an error code if there are any differences.
|
|
* `checkstyle` Will output the lines that need to be corrected as a checkstyle XML file,
|
|
that can be used by tools like Jenkins.
|
|
|
|
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=overwrite` by default.
|
|
|
|
If you want to restrict reformatting to specific sets of lines, you can
|
|
use the `--file-lines` option. Its argument is a JSON array of objects
|
|
with `file` and `range` properties, where `file` is a file name, and
|
|
`range` is an array representing a range of lines like `[7,13]`. Ranges
|
|
are 1-based and inclusive of both end points. Specifying an empty array
|
|
will result in no files being formatted. For example,
|
|
|
|
```
|
|
rustfmt --file-lines '[
|
|
{"file":"src/lib.rs","range":[7,13]},
|
|
{"file":"src/lib.rs","range":[21,29]},
|
|
{"file":"src/foo.rs","range":[10,11]},
|
|
{"file":"src/foo.rs","range":[15,15]}]'
|
|
```
|
|
|
|
would format lines `7-13` and `21-29` of `src/lib.rs`, and lines `10-11`,
|
|
and `15` of `src/foo.rs`. No other files would be formatted, even if they
|
|
are included as out of line modules from `src/lib.rs`.
|
|
|
|
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`.
|
|
|
|
You can run `rustfmt --help` for more information.
|
|
|
|
|
|
## Running Rustfmt from your editor
|
|
|
|
* [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.
|
|
|
|
## Checking style on a CI server
|
|
|
|
To keep your code base consistently formatted, it can be helpful to fail the CI build
|
|
when a pull request contains unformatted code. Using `--write-mode=diff` instructs
|
|
rustfmt to exit with an error code if the input is not formatted correctly.
|
|
It will also print any found differences.
|
|
|
|
(These instructions use the Syntex version of Rustfmt. If you want to use the
|
|
nightly version replace `install rustfmt` with `install rustfmt-nightly`,
|
|
however you must then only run this with the nightly toolchain).
|
|
|
|
A minimal Travis setup could look like this:
|
|
|
|
```yaml
|
|
language: rust
|
|
cache: cargo
|
|
before_script:
|
|
- export PATH="$PATH:$HOME/.cargo/bin"
|
|
- which rustfmt || cargo install rustfmt
|
|
script:
|
|
- cargo fmt -- --write-mode=diff
|
|
- cargo build
|
|
- cargo test
|
|
```
|
|
|
|
Note that using `cache: cargo` is optional but highly recommended to speed up the installation.
|
|
|
|
## How to build and test
|
|
|
|
`cargo build` to build.
|
|
|
|
`cargo test` to run all tests.
|
|
|
|
To run rustfmt after this, use `cargo run --bin rustfmt -- filename`. See the
|
|
notes above on running rustfmt.
|
|
|
|
|
|
## Configuring Rustfmt
|
|
|
|
Rustfmt is designed to be very configurable. You can create a TOML file called
|
|
`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
|
|
--config-help` 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 conforms to the [Rust style guide][style
|
|
guide]. For details that have not yet been formalized through the [style RFC
|
|
process][fmt rfcs], we try to adhere to a style similar to that used in the
|
|
[Rust repo][rust].
|
|
|
|
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.
|
|
|
|
|
|
## 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
|
|
#[cfg_attr(rustfmt, rustfmt_skip)] // works in stable
|
|
```
|
|
* 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.
|
|
* 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.
|
|
|
|
* If you get an error like `error while loading shared libraries` while starting
|
|
up rustfmt you should try the following:
|
|
|
|
On Linux:
|
|
|
|
```
|
|
export LD_LIBRARY_PATH=$(rustc --print sysroot)/lib:$LD_LIBRARY_PATH
|
|
```
|
|
|
|
On MacOS:
|
|
|
|
```
|
|
export DYLD_LIBRARY_PATH=$(rustc --print sysroot)/lib:$DYLD_LIBRARY_PATH
|
|
```
|
|
|
|
On Windows (Git Bash/Mingw):
|
|
|
|
```
|
|
export PATH=$(rustc --print sysroot)/lib/rustlib/x86_64-pc-windows-gnu/lib/:$PATH
|
|
```
|
|
|
|
(Substitute `x86_64` by `i686` and `gnu` by `msvc` depending on which version of rustc was used to install rustfmt).
|
|
|
|
## 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
|