fix: alert on mirror service outage instead of silently zeroing scores

gittensor/validator/issue_discovery/mirror_scan.py

@@ -150,7 +150,10 @@ async def run_mirror_issue_discovery(
         try:
             response = client.get_miner_issues(evaluation.github_id, since=lookback_date)
         except MirrorRequestError as e:
-            bt.logging.warning(f'├─ UID {uid}: mirror issue fetch failed ({e}) — skipped this miner')
+            bt.logging.error(
+                f'├─ UID {uid}: mirror issue fetch failed ({e}). '
+                f'Issue discovery score will be 0 for this miner this round.'
+            )
             fetch_errors += 1
             continue
 
@@ -190,6 +193,15 @@ async def run_mirror_issue_discovery(
         f'{cache_stats.fetch_failures} fetch failures)'
     )
 
+    if fetch_errors > 0:
+        total_eligible = processed + fetch_errors + no_issues
+        if total_eligible >= 5 and fetch_errors / total_eligible >= 0.5:
+            bt.logging.error(
+                f'High mirror issue-fetch failure rate: {fetch_errors}/{total_eligible} eligible miners '
+                f'failed ({fetch_errors / total_eligible:.0%}). Mirror service may be unavailable — '
+                f'issue discovery scores are 0 for all affected miners this round.'
+            )
+
 
 def _build_solving_pr_cache(
     miner_evaluations: Dict[int, MinerEvaluation],

gittensor/validator/oss_contributions/mirror/load.py

@@ -59,7 +59,11 @@ def load_mirror_miner_prs(
     try:
         response = client.get_miner_pulls(mirror_eval.github_id, since=lookback_date)
     except MirrorRequestError as e:
-        bt.logging.error(f'Mirror fetch failed for UID {mirror_eval.uid}: {e}')
+        bt.logging.error(
+            f'Mirror PR fetch failed for UID {mirror_eval.uid} '
+            f'(hotkey {mirror_eval.hotkey[:8]}): {e}. '
+            f'Mirror-enabled repo scores will be 0 this round for this miner.'
+        )
         mirror_eval.fetch_failed = True
         return
 

tests/validator/issue_discovery/test_mirror_scan.py

@@ -682,3 +682,66 @@ def test_all_mirror_miner_below_threshold_passes_spam(self):
         # Below threshold → spam_mult=1.0 → discovery score is non-zero
         assert eval_.issue_discovery_score > 0
         assert eval_.total_open_issues == 2
+
+
+# ============================================================================
+# Aggregate outage detection
+# ============================================================================
+
+
+class TestAggregateOutageDetection:
+    """Verify that a high fetch-failure rate triggers an error-level outage alert."""
+
+    def _run_with_patched_bt(self, evals, side_effect):
+        from unittest.mock import patch
+
+        client = Mock()
+        client.get_miner_issues.side_effect = side_effect
+        with patch('gittensor.validator.issue_discovery.mirror_scan.bt') as mock_bt:
+            _run(
+                run_mirror_issue_discovery(
+                    evals,
+                    _mirror_repos('entrius/gittensor-ui'),
+                    _EMPTY_LANGS,
+                    _EMPTY_TOKEN_CONFIG,
+                    client=client,
+                )
+            )
+        return mock_bt.logging.error.call_args_list
+
+    def _outage_logged(self, calls):
+        return any('Mirror service may be unavailable' in c.args[0] for c in calls)
+
+    def test_total_failure_across_ten_miners_logs_outage(self):
+        evals = {i: _eval(uid=i, github_id=f'g{i}') for i in range(10)}
+        calls = self._run_with_patched_bt(evals, MirrorRequestError('service unavailable'))
+        assert self._outage_logged(calls)
+
+    def test_majority_failure_at_boundary_logs_outage(self):
+        # 5 fail, 5 succeed (exactly 50%) — threshold is >= 0.5 so this fires
+        def _side(github_id, since=None):
+            return MirrorRequestError('boom') if github_id < 'g5' else _response([])
+
+        evals = {i: _eval(uid=i, github_id=f'g{i}') for i in range(10)}
+        calls = self._run_with_patched_bt(
+            evals,
+            lambda gid, since=None: (_ for _ in ()).throw(MirrorRequestError('boom')) if gid < 'g5' else _response([]),
+        )
+        assert self._outage_logged(calls)
+
+    def test_low_failure_rate_does_not_log_outage(self):
+        # 2 out of 10 fail = 20% — below threshold
+        def _side(github_id, since=None):
+            if github_id in ('g0', 'g1'):
+                raise MirrorRequestError('boom')
+            return _response([])
+
+        evals = {i: _eval(uid=i, github_id=f'g{i}') for i in range(10)}
+        calls = self._run_with_patched_bt(evals, _side)
+        assert not self._outage_logged(calls)
+
+    def test_small_population_guard_suppresses_alert(self):
+        # Only 3 miners — total_eligible < 5 guard prevents false positive
+        evals = {i: _eval(uid=i, github_id=f'g{i}') for i in range(3)}
+        calls = self._run_with_patched_bt(evals, MirrorRequestError('boom'))
+        assert not self._outage_logged(calls)