docs/versions/6.3.0/rules/lib/Label.mdx

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<h1 class="page-title" id="modules.Label">Label</h1>

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A BUILD target identifier.

<h2>Members</h2>
<ul>
    <li>
    <a href="#Label">Label</a>
  </li>
      <li>
    <a href="#name">name</a>
  </li>
      <li>
    <a href="#package">package</a>
  </li>
      <li>
    <a href="#relative">relative</a>
  </li>
      <li>
    <a href="#workspace_name">workspace_name</a>
  </li>
      <li>
    <a href="#workspace_root">workspace_root</a>
  </li>
  </ul>

      <h2 id="Label">Label</h2>
        <p><pre class="rule-signature"><a class="anchor" href="Label.html">Label</a> Label(input)</pre></p>

    Converts a label string into a <code>Label</code> object, in the context of the package where the calling <code>.bzl</code> source file lives. If the given value is already a <code>Label</code>, it is returned unchanged.<p>For macros, a related function, <code><a href='native#package_relative_label'>native.package_relative_label()</a></code>, converts the input into a <code>Label</code> in the context of the package currently being constructed. Use that function to mimic the string-to-label conversion that is automatically done by label-valued rule attributes.

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      <h3 class="hide-from-toc">Parameters</h3>
      <table class="table table-bordered table-condensed table-params">
        <colgroup>
          <col class="col-param">
          <col class="param-description">
        </colgroup>
        <thead>
          <tr>
            <th>Parameter</th>
            <th>Description</th>
          </tr>
        </thead>
        <tbody>
                  <tr>
            <td id="Label.input">
              <code>input</code>
            </td>
            <td>
                          <code><a class="anchor" href="string.html">string</a>; or <a class="anchor" href="Label.html">Label</a></code>;
                                     required<br/>
                          The input label string or Label object. If a Label object is passed, it's returned as is.
            </td>
          </tr>
                </tbody>
      </table>

        <h2 id="name">name</h2>
        <p><pre class="rule-signature"><a class="anchor" href="string.html">string</a> Label.name</pre></p>

    The name of this label within the package. For instance:<br><pre class=language-python>Label("//pkg/foo:abc").name == "abc"</pre>


        <h2 id="package">package</h2>
        <p><pre class="rule-signature"><a class="anchor" href="string.html">string</a> Label.package</pre></p>

    The package part of this label. For instance:<br><pre class=language-python>Label("//pkg/foo:abc").package == "pkg/foo"</pre>


        <h2 id="relative">relative</h2>
        <p><pre class="rule-signature"><a class="anchor" href="Label.html">Label</a> Label.relative(relName)</pre></p>

    Resolves a label that is either absolute (starts with <code>//</code>) or relative to the current package. If this label is in a remote repository, the argument will be resolved relative to that repository. If the argument contains a repository name, the current label is ignored and the argument is returned as-is, except that the repository name is rewritten if it is in the current repository mapping. Reserved labels will also be returned as-is.<br>For example:<br><pre class=language-python>
Label("//foo/bar:baz").relative(":quux") == Label("//foo/bar:quux")
Label("//foo/bar:baz").relative("//wiz:quux") == Label("//wiz:quux")
Label("@repo//foo/bar:baz").relative("//wiz:quux") == Label("@repo//wiz:quux")
Label("@repo//foo/bar:baz").relative("//visibility:public") == Label("//visibility:public")
Label("@repo//foo/bar:baz").relative("@other//wiz:quux") == Label("@other//wiz:quux")
</pre><p>If the repository mapping passed in is <code>{'@other' : '@remapped'}</code>, then the following remapping will take place:<br><pre class=language-python>
Label("@repo//foo/bar:baz").relative("@other//wiz:quux") == Label("@remapped//wiz:quux")
</pre>

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      <h3 class="hide-from-toc">Parameters</h3>
      <table class="table table-bordered table-condensed table-params">
        <colgroup>
          <col class="col-param">
          <col class="param-description">
        </colgroup>
        <thead>
          <tr>
            <th>Parameter</th>
            <th>Description</th>
          </tr>
        </thead>
        <tbody>
                  <tr>
            <td id="relative.relName">
              <code>relName</code>
            </td>
            <td>
                                     required<br/>
                          The label that will be resolved relative to this one.
            </td>
          </tr>
                </tbody>
      </table>

        <h2 id="workspace_name">workspace_name</h2>
        <p><pre class="rule-signature"><a class="anchor" href="string.html">string</a> Label.workspace_name</pre></p>

    The repository part of this label. For instance, <pre class=language-python>Label("@foo//bar:baz").workspace_name == "foo"</pre>


        <h2 id="workspace_root">workspace_root</h2>
        <p><pre class="rule-signature"><a class="anchor" href="string.html">string</a> Label.workspace_root</pre></p>

    Returns the execution root for the workspace of this label, relative to the execroot. For instance:<br><pre class=language-python>Label("@repo//pkg/foo:abc").workspace_root == "external/repo"</pre>



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