gh-merge-green: allow explicit Vercel status override

scripts/gh-merge-green

@@ -139,6 +139,13 @@ if [ -n "$override_reason" ]; then
       'explain the concrete red check and why this exact head is safe to merge'
   fi
 fi
+skip_vercel=0
+if [ -n "$override_reason" ] && [[ "$override_reason" =~ [Vv]ercel ]]; then
+  # Vercel is an optional preview deployment status in this repository.  An
+  # explicit, auditable override may waive that one external status when it is
+  # pending or red; all other pending statuses remain merge blockers.
+  skip_vercel=1
+fi
 if [ "$fix" -eq 1 ] && [ -n "$override_reason" ]; then
   refuse \
     'not green: --override cannot be combined with --main-fix' \
@@ -477,6 +484,10 @@ if [ "$has_ci" -eq 0 ]; then
   while IFS=$'\t' read -r name st co; do
     [ -n "$name" ] || continue
     reported=$((reported + 1))
+    if [ "$skip_vercel" -eq 1 ] && [ "$name" = Vercel ]; then
+      echo "note: --override waived Vercel $st/$co status" >&2
+      continue
+    fi
     if [ "$st" != completed ]; then
       refuse \
         "not green: '$name' is $st/$co on $sha (no ci-status workflow on base $base)" \

tests/test_gh_merge_green.py

@@ -686,7 +686,7 @@ class WorkflowPresenceRegression(unittest.TestCase):
     """Repositories without the aggregate workflow use all exact-head verdicts."""
 
     def run_case(self, *, workflow=False, probe_status=404, checks=None, statuses=None, app_workflow=False, files=None, workflow_body=None,
-                 raw_content=None, app_workflow_body=None):
+                 raw_content=None, app_workflow_body=None, extra_args=()):
         with tempfile.TemporaryDirectory() as directory:
             directory = Path(directory)
             marker = directory / "merged"
@@ -706,6 +706,8 @@ def run_case(self, *, workflow=False, probe_status=404, checks=None, statuses=No
                 with open(os.environ['QUERIES'], 'a') as f: f.write(' '.join(a) + '\n')
                 if a[:2] == ['pr', 'view']:
                     print(json.dumps({'headRefOid': x['head'], 'baseRefName': 'main', 'state': 'OPEN'}))
+                elif a[:2] == ['pr', 'comment']:
+                    pass
                 elif a[:2] == ['pr', 'merge']:
                     Path(os.environ['MERGE_MARKER']).touch()
                 elif a[0] == 'api' and any('/contents/' in arg for arg in a):
@@ -731,7 +733,7 @@ def run_case(self, *, workflow=False, probe_status=404, checks=None, statuses=No
                     sys.exit(2)
                 """))
             gh.chmod(0o755)
-            result = subprocess.run([str(ROOT / 'scripts/gh-merge-green'), 'manaflow-ai/cmuxterm-hq#1254', '--squash'],
+            result = subprocess.run([str(ROOT / 'scripts/gh-merge-green'), 'manaflow-ai/cmuxterm-hq#1254', *extra_args, '--squash'],
                 env={**os.environ, 'PATH': str(directory) + os.pathsep + os.environ['PATH'], 'FIXTURE': str(fixture), 'MERGE_MARKER': str(marker), 'QUERIES': str(queries), 'GH_MERGE_GREEN_NO_AUTO_UPDATE': '1'}, capture_output=True, text=True)
             return result, marker.exists(), queries.read_text()
 
@@ -763,6 +765,18 @@ def test_no_ci_workflow_refuses_pending_status_context(self):
         self.assertNotEqual(result.returncode, 0)
         self.assertFalse(merged)
 
+    def test_vercel_override_waives_only_the_named_external_status(self):
+        result, merged, _ = self.run_case(
+            statuses=[{'id': 2, 'context': 'Vercel', 'state': 'pending'}],
+            extra_args=("--override", "Vercel preview is unrelated to this CLI change"))
+        self.assertEqual(result.returncode, 0, result.stderr)
+        self.assertTrue(merged)
+        result, merged, _ = self.run_case(
+            statuses=[{'id': 2, 'context': 'review', 'state': 'pending'}],
+            extra_args=("--override", "Vercel preview is unrelated to this CLI change"))
+        self.assertNotEqual(result.returncode, 0)
+        self.assertFalse(merged)
+
     def test_workflow_probe_failure_is_not_absence(self):
         for code in (403, 500):
             result, merged, _ = self.run_case(probe_status=code)