Allow passing a bazel path to vendor explicitly (bazelbuild#1661)

Co-authored-by: David Koloski <dkoloski@google.com>
Co-authored-by: UebelAndre <github@uebelandre.com>

crate_universe/private/crates_vendor.bzl

@@ -225,6 +225,11 @@ def _crates_vendor_impl(ctx):
         args.extend(["--buildifier", _runfiles_path(ctx.executable.buildifier, is_windows)])
         cargo_bazel_runfiles.append(ctx.executable.buildifier)
 
+    # Optionally include an explicit `bazel` path
+    if ctx.attr.bazel:
+        args.extend(["--bazel", _runfiles_path(ctx.executable.bazel, is_windows)])
+        cargo_bazel_runfiles.append(ctx.executable.bazel)
+
     # Determine platform specific settings
     if is_windows:
         extension = ".bat"
@@ -334,6 +339,12 @@ call against the generated workspace. The following table describes how to contr
         "annotations": attr.string_list_dict(
             doc = "Extra settings to apply to crates. See [crate.annotation](#crateannotation).",
         ),
+        "bazel": attr.label(
+            doc = "The path to a bazel binary used to locate the output_base for the current workspace.",
+            cfg = "exec",
+            executable = True,
+            allow_files = True,
+        ),
         "buildifier": attr.label(
             doc = "The path to a [buildifier](https://github.com/bazelbuild/buildtools/blob/5.0.1/buildifier/README.md) binary used to format generated BUILD files.",
             cfg = "exec",

docs/crate_universe.md

@@ -302,7 +302,7 @@ that is called behind the scenes to update dependencies.
 ## crates_vendor
 
 <pre>
-crates_vendor(<a href="#crates_vendor-name">name</a>, <a href="#crates_vendor-annotations">annotations</a>, <a href="#crates_vendor-buildifier">buildifier</a>, <a href="#crates_vendor-cargo_bazel">cargo_bazel</a>, <a href="#crates_vendor-cargo_config">cargo_config</a>, <a href="#crates_vendor-cargo_lockfile">cargo_lockfile</a>,
+crates_vendor(<a href="#crates_vendor-name">name</a>, <a href="#crates_vendor-annotations">annotations</a>, <a href="#crates_vendor-bazel">bazel</a>, <a href="#crates_vendor-buildifier">buildifier</a>, <a href="#crates_vendor-cargo_bazel">cargo_bazel</a>, <a href="#crates_vendor-cargo_config">cargo_config</a>, <a href="#crates_vendor-cargo_lockfile">cargo_lockfile</a>,
               <a href="#crates_vendor-generate_build_scripts">generate_build_scripts</a>, <a href="#crates_vendor-manifests">manifests</a>, <a href="#crates_vendor-mode">mode</a>, <a href="#crates_vendor-packages">packages</a>, <a href="#crates_vendor-repository_name">repository_name</a>, <a href="#crates_vendor-splicing_config">splicing_config</a>,
               <a href="#crates_vendor-supported_platform_triples">supported_platform_triples</a>, <a href="#crates_vendor-vendor_path">vendor_path</a>)
 </pre>
@@ -386,6 +386,7 @@ call against the generated workspace. The following table describes how to contr
 | :------------- | :------------- | :------------- | :------------- | :------------- |
 | <a id="crates_vendor-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/docs/build-ref.html#name">Name</a> | required |  |
 | <a id="crates_vendor-annotations"></a>annotations |  Extra settings to apply to crates. See [crate.annotation](#crateannotation).   | <a href="https://bazel.build/docs/skylark/lib/dict.html">Dictionary: String -> List of strings</a> | optional | {} |
+| <a id="crates_vendor-bazel"></a>bazel |  The path to a bazel binary used to locate the output_base for the current workspace.   | <a href="https://bazel.build/docs/build-ref.html#labels">Label</a> | optional | None |
 | <a id="crates_vendor-buildifier"></a>buildifier |  The path to a [buildifier](https://github.com/bazelbuild/buildtools/blob/5.0.1/buildifier/README.md) binary used to format generated BUILD files.   | <a href="https://bazel.build/docs/build-ref.html#labels">Label</a> | optional | //crate_universe/private/vendor:buildifier |
 | <a id="crates_vendor-cargo_bazel"></a>cargo_bazel |  The cargo-bazel binary to use for vendoring. If this attribute is not set, then a <code>CARGO_BAZEL_GENERATOR_PATH</code> action env will be used.   | <a href="https://bazel.build/docs/build-ref.html#labels">Label</a> | optional | @cargo_bazel_bootstrap//:binary |
 | <a id="crates_vendor-cargo_config"></a>cargo_config |  A [Cargo configuration](https://doc.rust-lang.org/cargo/reference/config.html) file.   | <a href="https://bazel.build/docs/build-ref.html#labels">Label</a> | optional | None |