Invalidate lockfile entry when the extension name prefix changes

This was missed in bazelbuild#19055.

Closes bazelbuild#23527.

PiperOrigin-RevId: 672480631
Change-Id: Ib2ef0edb6b6c90a7336085da20e2794a93763182

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/SingleExtensionUsagesValue.java

@@ -83,9 +83,7 @@ SingleExtensionUsagesValue trimForEvaluation() {
     return SingleExtensionUsagesValue.create(
         ImmutableMap.copyOf(
             Maps.transformValues(getExtensionUsages(), ModuleExtensionUsage::trimForEvaluation)),
-        // extensionUniqueName: Not accessible to the extension's implementation function.
-        // TODO: Reconsider this when resolving #19055.
-        "",
+        getExtensionUniqueName(),
         getAbridgedModules(),
         // repoMappings: The usage of repo mappings by the extension's implementation function is
         // tracked on the level of individual entries and all label attributes are provided as

src/test/py/bazel/bzlmod/bazel_lockfile_test.py

@@ -2602,6 +2602,61 @@ def testLockFileVersionIsCorrectWithUsePlusFlag(self):
     self.RunBazel(['clean', '--expunge'])
     self.RunBazel(['mod', 'graph', '--incompatible_use_plus_in_repo_names',
                    '--lockfile_mode=error'])
+  def testModuleExtensionRerunsOnUniqueNameChange(self):
+    self.ScratchFile(
+        'MODULE.bazel',
+        [
+            'my_ext_1 = use_extension("//:ext1.bzl","my_ext")',
+            'use_repo(my_ext_1, "foo")',
+        ],
+    )
+    self.ScratchFile('BUILD.bazel')
+    self.ScratchFile(
+        'ext1.bzl',
+        [
+            'def _my_repo_impl(ctx):',
+            '  ctx.file("REPO.bazel")',
+            '  ctx.file("BUILD")',
+            '  ctx.file("hi.txt", "hi")',
+            '  if ctx.attr.label:',
+            '    print("label: {}".format(ctx.attr.label))',
+            'my_repo = repository_rule(',
+            '  implementation=_my_repo_impl,',
+            '  attrs={"label": attr.label()}',
+            ')',
+            'def _my_ext_impl(ctx):',
+            '  my_repo(name="foo",label="@bar")',
+            '  my_repo(name="bar")',
+            'my_ext = module_extension(implementation=_my_ext_impl)',
+        ],
+    )
+    self.ScratchFile(
+        'ext2.bzl',
+        [
+            'load(":ext1.bzl", "my_repo")',
+            'def _my_ext_impl(ctx):',
+            '  my_repo(name="foo")',
+            'my_ext = module_extension(implementation=_my_ext_impl)',
+        ],
+    )
+
+    _, _, stderr = self.RunBazel(['build', '@foo//:all'])
+    stderr = '\n'.join(stderr)
+    self.assertIn('label: @@+my_ext+bar//:bar\n', stderr)
+
+    self.ScratchFile(
+        'MODULE.bazel',
+        [
+            'my_ext_2 = use_extension("//:ext2.bzl","my_ext")',
+            'use_repo(my_ext_2, other_foo = "foo")',
+            'my_ext_1 = use_extension("//:ext1.bzl","my_ext")',
+            'use_repo(my_ext_1, "foo")',
+        ],
+    )
+
+    _, _, stderr = self.RunBazel(['build', '@foo//:all'])
+    stderr = '\n'.join(stderr)
+    self.assertIn('label: @@+my_ext2+bar//:bar\n', stderr)
 
 
 if __name__ == '__main__':