fix: matrix baseline override keeps resolved global on invalid merge (#2179)

Codex round-2 finding: resolveVoiceDriftConfig merged the RAW global config with
the series override and let resolveCheckConfig collapse the whole blob to bare
schema defaults if the merge was invalid — while the finding-emitting
applySeriesCheckConfig keeps the resolved global on an invalid override. A bad
per-series value (e.g. sigmaThreshold beyond the schema max) would make the
matrix use the default 1.5 while findings used the global threshold, re-opening
the matrix/finding disagreement. Now resolves the global first, then overlays
the override on it, keeping the resolved global on parse failure — byte-for-byte
the applySeriesCheckConfig contract.

Refs #2179

Author: atomantic

server/services/pipeline/voiceFingerprint.js

@@ -58,16 +58,19 @@ export async function resolveVoiceDriftConfig(settings, seriesOverrides) {
   const s = settings || await getSettings();
   const check = getCheckById(s, VOICE_DRIFT_CHECK_ID);
   const stored = readChecksSlice(s)[VOICE_DRIFT_CHECK_ID]?.config;
+  // Resolve the GLOBAL config first (schema-validated, defaults filled).
+  const global = resolveCheckConfig(check, stored);
   const override = seriesOverrides && typeof seriesOverrides === 'object' && !Array.isArray(seriesOverrides)
     ? seriesOverrides[VOICE_DRIFT_CHECK_ID]
     : null;
-  // Overlay the per-series override on the global stored config before validating,
-  // mirroring applySeriesCheckConfig's `{ ...config, ...override }` merge. A
-  // non-object override is ignored (the spread of a non-object is a no-op).
-  const merged = (override && typeof override === 'object' && !Array.isArray(override))
-    ? { ...(stored || {}), ...override }
-    : stored;
-  return resolveCheckConfig(check, merged);
+  if (!override || typeof override !== 'object' || Array.isArray(override)) return global;
+  // Overlay the per-series override on the RESOLVED global, EXACTLY as
+  // applySeriesCheckConfig does — including its failure mode: if the merged blob
+  // is invalid (e.g. a hand-edited out-of-range value), keep the resolved global
+  // rather than collapsing to bare schema defaults, so the matrix view and the
+  // finding-emitting run stay in lockstep even on a bad override.
+  const parsed = check.configSchema.safeParse({ ...global, ...override });
+  return parsed.success ? parsed.data : global;
 }
 
 /**

server/services/pipeline/voiceFingerprint.test.js

@@ -88,6 +88,21 @@ describe('resolveVoiceDriftConfig', () => {
     const cfg = await resolveVoiceDriftConfig(undefined, { [VOICE_DRIFT_CHECK_ID]: 'nope' });
     expect(cfg.baselineMode).toBe('drafted');
   });
+
+  it('keeps the resolved global config when a per-series override is invalid (#1591 parity)', async () => {
+    // Mirror applySeriesCheckConfig: an out-of-range override must NOT collapse the
+    // matrix to bare schema defaults — it keeps the resolved global, so the matrix
+    // view and the finding-emitting run agree even on a bad override.
+    settingsStore = {
+      pipelineEditorialChecks: {
+        checks: { [VOICE_DRIFT_CHECK_ID]: { config: { sigmaThreshold: 2.5 } } },
+      },
+    };
+    const cfg = await resolveVoiceDriftConfig(undefined, {
+      [VOICE_DRIFT_CHECK_ID]: { sigmaThreshold: 999999 }, // > schema max(4) → invalid merge
+    });
+    expect(cfg.sigmaThreshold).toBe(2.5); // resolved global, NOT the default 1.5
+  });
 });
 
 describe('getVoiceFingerprint', () => {