feat: require live blocker proof before skipping earlier PRs (Closes #318)

Add assess_prior_blocker_skip_proof to validate reviewer reports document
live REQUEST_CHANGES blocker proof for skipped earlier open PRs, reject
stale-memory skips when head changed after blocker, and require
BLOCKER_STATUS_UNVERIFIED when review feedback cannot be fetched.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

tests/test_llm_workflow_split.py

@@ -121,4 +121,10 @@ def test_start_issue_template_references_work_issue_workflow():
 def test_create_issue_final_report_verifier_exported():
     from review_proofs import assess_create_issue_final_report
 
-    assert callable(assess_create_issue_final_report)
+    assert callable(assess_create_issue_final_report)
+
+
+def test_prior_blocker_skip_verifier_exported():
+    from review_proofs import assess_prior_blocker_skip_proof
+
+    assert callable(assess_prior_blocker_skip_proof)

tests/test_reviewer_blocker_skip.py

@@ -0,0 +1,139 @@
+"""Tests for prior-blocker skip proof verifier (#318)."""
+import sys
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from reviewer_blocker_skip import assess_prior_blocker_skip_proof  # noqa: E402
+
+HEAD_CURRENT = "0fdc8f582026b72a229d59a172c0a63ac4aaeaf9"
+HEAD_BLOCKER = "1111111111111111111111111111111111111111"
+
+
+def _good_blocker_skip_report(pr_number: int) -> str:
+    return "\n".join([
+        f"Skipped PR #{pr_number} due to prior REQUEST_CHANGES.",
+        f"- PR number: #{pr_number}",
+        f"- Current head SHA: {HEAD_CURRENT}",
+        "- Blocking review decision: request_changes",
+        f"- Blocking review head SHA: {HEAD_CURRENT}",
+        "- Head unchanged since blocker",
+        "- Reason remains blocked: unresolved review feedback at same head",
+        "- Blocker revalidated live in this session via gitea_get_pr_review_feedback",
+    ])
+
+
+class TestPriorBlockerSkipProof(unittest.TestCase):
+    def test_no_skips_passes(self):
+        result = assess_prior_blocker_skip_proof(
+            "Selected PR #281 for review.",
+            skipped_prs=[],
+        )
+        self.assertTrue(result["proven"])
+
+    def test_blocked_unchanged_with_live_proof_passes(self):
+        report = _good_blocker_skip_report(280)
+        result = assess_prior_blocker_skip_proof(
+            report,
+            skipped_prs=[{
+                "pr_number": 280,
+                "head_sha": HEAD_CURRENT,
+                "blocking_decision": "request_changes",
+                "blocking_review_head_sha": HEAD_CURRENT,
+                "head_changed_since_blocker": False,
+                "blocker_verified": True,
+            }],
+        )
+        self.assertTrue(result["proven"])
+
+    def test_head_changed_after_blocker_blocks_skip(self):
+        result = assess_prior_blocker_skip_proof(
+            _good_blocker_skip_report(280),
+            skipped_prs=[{
+                "pr_number": 280,
+                "head_sha": HEAD_CURRENT,
+                "blocking_decision": "request_changes",
+                "blocking_review_head_sha": HEAD_BLOCKER,
+                "head_changed_since_blocker": True,
+                "blocker_verified": True,
+            }],
+        )
+        self.assertFalse(result["proven"])
+        self.assertTrue(any("head changed" in r for r in result["reasons"]))
+
+    def test_missing_live_proof_blocks(self):
+        report = _good_blocker_skip_report(280).replace(
+            "- Blocker revalidated live in this session via gitea_get_pr_review_feedback",
+            "",
+        )
+        result = assess_prior_blocker_skip_proof(
+            report,
+            skipped_prs=[{
+                "pr_number": 280,
+                "head_sha": HEAD_CURRENT,
+                "blocking_decision": "request_changes",
+                "blocking_review_head_sha": HEAD_CURRENT,
+                "head_changed_since_blocker": False,
+                "blocker_verified": True,
+            }],
+        )
+        self.assertFalse(result["proven"])
+        self.assertTrue(any("live blocker proof" in r for r in result["reasons"]))
+
+    def test_blocker_unverified_classification_passes(self):
+        report = "\n".join([
+            "Skipped PR #280.",
+            "Classification: BLOCKER_STATUS_UNVERIFIED",
+            "Review feedback could not be fetched live in this session.",
+        ])
+        result = assess_prior_blocker_skip_proof(
+            report,
+            skipped_prs=[{
+                "pr_number": 280,
+                "blocking_decision": "request_changes",
+                "blocker_verified": False,
+            }],
+        )
+        self.assertTrue(result["proven"])
+
+    def test_unverified_without_classification_blocks(self):
+        result = assess_prior_blocker_skip_proof(
+            "Skipped PR #280 based on memory from last session.",
+            skipped_prs=[{
+                "pr_number": 280,
+                "blocking_decision": "request_changes",
+                "blocker_verified": False,
+            }],
+        )
+        self.assertFalse(result["proven"])
+        self.assertTrue(any("BLOCKER_STATUS_UNVERIFIED" in r for r in result["reasons"]))
+
+    def test_missing_blocking_head_sha_blocks(self):
+        report = _good_blocker_skip_report(280).replace(
+            f"- Blocking review head SHA: {HEAD_CURRENT}",
+            "",
+        )
+        result = assess_prior_blocker_skip_proof(
+            report,
+            skipped_prs=[{
+                "pr_number": 280,
+                "head_sha": HEAD_CURRENT,
+                "blocking_decision": "request_changes",
+                "blocking_review_head_sha": HEAD_CURRENT,
+                "head_changed_since_blocker": False,
+                "blocker_verified": True,
+            }],
+        )
+        self.assertFalse(result["proven"])
+
+
+class TestExport(unittest.TestCase):
+    def test_review_proofs_reexport(self):
+        from review_proofs import assess_prior_blocker_skip_proof as exported
+
+        self.assertTrue(callable(exported))
+
+
+if __name__ == "__main__":
+    unittest.main()