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-to be a bit out of date).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.
+[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 use `rustfmt` on Rust 1.24 and above.
+You can run `rustfmt` with Rust 1.24 and above.
To install:
cargo fmt
```
+For the latest and greatest `rustfmt` (nightly required):
+```
+rustup component add rustfmt-preview --toolchain nightly
+```
+To run:
+```
+cargo +nightly fmt
+```
+
+## 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
```
## Installing from source
-To install from source, first checkout to the tag or branch you want to install, then issue
+To install from source (nightly required), first checkout to the tag or branch you want to install, then issue
+
```
-cargo install --path .
+cargo install --path .
```
This will install `rustfmt` in your `~/.cargo/bin`. Make sure to add `~/.cargo/bin` directory to
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.
+You can run `rustfmt --help` for information about argument.
-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,
+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).
-```
-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 syntactically 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
* [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.
+* [IntelliJ or CLion](intellij.md)
+
## 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
+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.
+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:
+A minimal Travis setup could look like this (requires Rust 1.24.0 or greater):
```yaml
language: rust
before_script:
-- rustup toolchain install nightly
-- rustup component add --toolchain nightly rustfmt-preview
-- which rustfmt || cargo install --force rustfmt-nightly
+- rustup component add rustfmt-preview
script:
-- cargo +nightly fmt --all -- --write-mode=diff
+- 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
`cargo build` to build.
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
+--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 conforms to the [Rust style guide][style
* 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` 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 --dump-default-config rustfmt.toml` and customize as needed.
+ `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.
-* If you get an error like `error while loading shared libraries` while starting
- up rustfmt you should try the following:
+* You can change the way rustfmt emits the changes with the --emit flag:
- On Linux:
+ Example:
```
- export LD_LIBRARY_PATH=$(rustc --print sysroot)/lib:$LD_LIBRARY_PATH
+ cargo fmt -- --emit files
```
- 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
- ```
+ Options:
- (Substitute `x86_64` by `i686` and `gnu` by `msvc` depending on which version of rustc was used to install rustfmt).
+ | 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
projects / rust.git / blobdiff