171d917888
Quick fix for "impl Trait" |
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src | ||
tests | ||
.gitignore | ||
.travis.yml | ||
appveyor.yml | ||
atom.md | ||
bootstrap.sh | ||
build.rs | ||
Cargo.lock | ||
Cargo.toml | ||
Contributing.md | ||
Design.md | ||
LICENSE-APACHE | ||
LICENSE-MIT | ||
README.md |
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.
Quick start
To install:
cargo install rustfmt
to run on a cargo project in the current working directory:
cargo fmt
Installation
Note: this method currently requires you to be running cargo 0.6.0 or newer.
cargo install rustfmt
or if you're using rustup.rs
rustup run nightly cargo install rustfmt
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
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, and checkstyle.
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. 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=replace
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
- Emacs
- Sublime Text 3
- Atom
- Visual Studio Code using RustyCode or vsc-rustfmt
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.
A minimal Travis setup could look like this:
language: rust
cache: cargo
before_script: (cargo install rustfmt || true)
script:
- |
export PATH=$PATH:~/.cargo/bin &&
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
source code, src/config.rs.
By default, Rustfmt uses a style which (mostly) conforms to the Rust style guidelines. 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. 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.
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
#[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.
License
Rustfmt is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT for details.