Fix resolveToModuleKeys when checking module extension

Fixes bazelbuild#21621 (comment)

PiperOrigin-RevId: 625286656
Change-Id: Ibc5d153af96912de39b146e50f081030d1da7257

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

@@ -305,7 +305,7 @@ public ImmutableSet<ModuleKey> resolveToModuleKeys(
  throws InvalidArgumentException {
  Optional<AugmentedModule> mod =
  depGraph.values().stream()
- .filter(m -> moduleKeyToCanonicalNames.get(m.getKey()).equals(repoName()))
+ .filter(m -> repoName().equals(moduleKeyToCanonicalNames.get(m.getKey())))
  .findAny();
  if (mod.isPresent() && !includeUnused && warnUnused && !mod.get().isUsed()) {
  // Warn the user when unused modules are allowed and the specified version exists, but the

src/test/py/bazel/bzlmod/mod_command_test.py

@@ -365,6 +365,22 @@ def testShowExtensionSomeExtensionsSomeUsages(self):
  'Wrong output in the show with some extensions and some usages query.',
  )
 
+ def testShowExtensionWithUnknownRepo(self):
+ _, _, stderr = self.RunBazel(
+ [
+ 'mod',
+ 'show_extension',
+ '@@unknown//foo:bar.bzl%x',
+ ],
+ allow_failure=True,
+ rstrip=True,
+ )
+ self.assertIn(
+ 'ERROR: In extension argument @@unknown//foo:bar.bzl%x: No module with '
+ 'the canonical repo name @@unknown exists in the dependency graph.',
+ '\n'.join(stderr),
+ )
+
  def testShowModuleAndExtensionReposFromBaseModule(self):
  _, stdout, _ = self.RunBazel(
  [