🐛 fix(thirdparty): expose main in mirror fixture

test/test_thirdparty_skills_pipeline.py

@@ -254,6 +254,26 @@ class ThirdpartySkillsPipelineTests(unittest.TestCase):
             clone_mirror = run_command("git", "clone", "--mirror", str(ROOT), str(mirror))
             self.assertEqual(clone_mirror.returncode, 0, msg=clone_mirror.stderr)
 
+            main_ref = run_command(
+                "git",
+                f"--git-dir={mirror}",
+                "rev-parse",
+                "refs/remotes/origin/main",
+            )
+            self.assertEqual(main_ref.returncode, 0, msg=main_ref.stderr)
+            expose_main_branch = run_command(
+                "git",
+                f"--git-dir={mirror}",
+                "update-ref",
+                "refs/heads/main",
+                main_ref.stdout.strip(),
+            )
+            self.assertEqual(
+                expose_main_branch.returncode,
+                0,
+                msg=expose_main_branch.stderr,
+            )
+
             thirdparty_ref = run_command(
                 "git",
                 f"--git-dir={mirror}",