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<h1 class="menu-title">rules_rust</h1>
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<h2 id="overview"><a class="header" href="#overview">Overview</a></h2>
<p><a href="https://github.com/rust-lang/rustfmt#readme">Rustfmt</a> is a tool for formatting Rust code according to style guidelines.
By default, Rustfmt uses a style which conforms to the <a href="https://github.com/rust-lang-nursery/fmt-rfcs/blob/master/guide/guide.md">Rust style guide</a> that
has been formalized through the <a href="https://github.com/rust-lang-nursery/fmt-rfcs">style RFC process</a>. A complete list of all
configuration options can be found in the <a href="https://rust-lang.github.io/rustfmt/">Rustfmt GitHub Pages</a>.</p>
<h3 id="setup"><a class="header" href="#setup">Setup</a></h3>
<p>Formatting your Rust targets' source code requires no setup outside of loading <code>rules_rust</code>
in your workspace. Simply run <code>bazel run @rules_rust//:rustfmt</code> to format source code.</p>
<p>In addition to this formatter, a simple check can be performed using the <a href="#rustfmt-aspect">rustfmt_aspect</a> aspect by running</p>
<pre><code class="language-text">bazel build --aspects=@rules_rust//rust:defs.bzl%rustfmt_aspect --output_groups=rustfmt_checks
</code></pre>
<p>Add the following to a <code>.bazelrc</code> file to enable this check during the build phase.</p>
<pre><code class="language-text">build --aspects=@rules_rust//rust:defs.bzl%rustfmt_aspect
build --output_groups=+rustfmt_checks
</code></pre>
<p>It's recommended to only enable this aspect in your CI environment so formatting issues do not
impact user's ability to rapidly iterate on changes.</p>
<p>The <code>rustfmt_aspect</code> also uses a <code>--@rules_rust//rust/settings:rustfmt.toml</code> setting which determines the
<a href="https://rust-lang.github.io/rustfmt/">configuration file</a> used by the formatter (<code>@rules_rust//tools/rustfmt</code>) and the aspect
(<code>rustfmt_aspect</code>). This flag can be added to your <code>.bazelrc</code> file to ensure a consistent config
file is used whenever <code>rustfmt</code> is run:</p>
<pre><code class="language-text">build --@rules_rust//rust/settings:rustfmt.toml=//:rustfmt.toml
</code></pre>
<h3 id="tips"><a class="header" href="#tips">Tips</a></h3>
<p>Any target which uses Bazel generated sources will cause the <code>@rules_rust//tools/rustfmt</code> tool to fail with
<code>failed to resolve mod `MOD` </code>. To avoid failures, <a href="https://rust-lang.github.io/rustfmt/?version=v1.6.0&amp;search=skip_chil#skip_children"><code>skip_children = true</code></a>
is recommended to be set in the workspace's <code>rustfmt.toml</code> file which allows rustfmt to run on these targets
without failing.</p>
<h2 id="rules"><a class="header" href="#rules">Rules</a></h2>
<ul>
<li><a href="#rustfmt_test">rustfmt_test</a></li>
</ul>
<h2 id="aspects"><a class="header" href="#aspects">Aspects</a></h2>
<ul>
<li><a href="#rustfmt_aspect">rustfmt_aspect</a></li>
</ul>
<p><a id="rustfmt_test"></a></p>
<h2 id="rustfmt_test"><a class="header" href="#rustfmt_test">rustfmt_test</a></h2>
<pre>
load("@rules_rust//rust:defs.bzl", "rustfmt_test")
rustfmt_test(<a href="#rustfmt_test-name">name</a>, <a href="#rustfmt_test-targets">targets</a>)
</pre>
<p>A test rule for performing <code>rustfmt --check</code> on a set of targets</p>
<p><strong>ATTRIBUTES</strong></p>
<div class="table-wrapper"><table><thead><tr><th style="text-align: left">Name</th><th style="text-align: left">Description</th><th style="text-align: left">Type</th><th style="text-align: left">Mandatory</th><th style="text-align: left">Default</th></tr></thead><tbody>
<tr><td style="text-align: left"><a id="rustfmt_test-name"></a>name</td><td style="text-align: left">A unique name for this target.</td><td style="text-align: left"><a href="https://bazel.build/concepts/labels#target-names">Name</a></td><td style="text-align: left">required</td><td style="text-align: left"></td></tr>
<tr><td style="text-align: left"><a id="rustfmt_test-targets"></a>targets</td><td style="text-align: left">Rust targets to run <code>rustfmt --check</code> on.</td><td style="text-align: left"><a href="https://bazel.build/concepts/labels">List of labels</a></td><td style="text-align: left">optional</td><td style="text-align: left"><code>[]</code></td></tr>
</tbody></table>
</div>
<p><a id="rustfmt_aspect"></a></p>
<h2 id="rustfmt_aspect"><a class="header" href="#rustfmt_aspect">rustfmt_aspect</a></h2>
<pre>
load("@rules_rust//rust:defs.bzl", "rustfmt_aspect")
rustfmt_aspect(<a href="#rustfmt_aspect-name">name</a>)
</pre>
<p>This aspect is used to gather information about a crate for use in rustfmt and perform rustfmt checks</p>
<p>Output Groups:</p>
<ul>
<li><code>rustfmt_checks</code>: Executes <code>rustfmt --check</code> on the specified target.</li>
</ul>
<p>The build setting <code>@rules_rust//rust/settings:rustfmt.toml</code> is used to control the Rustfmt <a href="https://rust-lang.github.io/rustfmt/">configuration settings</a>
used at runtime.</p>
<p>This aspect is executed on any target which provides the <code>CrateInfo</code> provider. However
users may tag a target with <code>no-rustfmt</code> or <code>no-format</code> to have it skipped. Additionally,
generated source files are also ignored by this aspect.</p>
<p><strong>ASPECT ATTRIBUTES</strong></p>
<p><strong>ATTRIBUTES</strong></p>
<div class="table-wrapper"><table><thead><tr><th style="text-align: left">Name</th><th style="text-align: left">Description</th><th style="text-align: left">Type</th><th style="text-align: left">Mandatory</th><th style="text-align: left">Default</th></tr></thead><tbody>
<tr><td style="text-align: left"><a id="rustfmt_aspect-name"></a>name</td><td style="text-align: left">A unique name for this target.</td><td style="text-align: left"><a href="https://bazel.build/concepts/labels#target-names">Name</a></td><td style="text-align: left">required</td><td style="text-align: left"></td></tr>
</tbody></table>
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