fix(signals): diff all registry config fields in change reports

src/signals/engine.ts

@@ -11,6 +11,7 @@ import type {
   PullRequestRecord,
   PullRequestReviewRecord,
   RecentMergedPullRequestRecord,
+  RegistryRepoConfig,
   RegistrySnapshot,
   RepoLabelRecord,
   RepoSyncStateRecord,
@@ -3019,6 +3020,33 @@ export function buildCollisionEdges(report: CollisionReport): CollisionEdgeRecor
   });
 }
 
+// All comparable RegistryRepoConfig fields, rendered to a stable string for diffing.
+// Mirrors REGISTRY_DRIFT_COMPARABLE_FIELDS in upstream/ruleset.ts so the live change
+// report and the drift comparator cannot diverge as config fields are added — every
+// scoring-relevant field (fixed_base_score, default_label_multiplier, eligibility_mode)
+// is covered, not just the emission/lane subset.
+const REGISTRY_CHANGE_FIELDS: Array<{ label: string; render: (config: RegistryRepoConfig) => string }> = [
+  { label: "emission_share", render: (config) => String(config.emissionShare) },
+  { label: "issue_discovery_share", render: (config) => String(config.issueDiscoveryShare) },
+  { label: "maintainer_cut", render: (config) => String(config.maintainerCut) },
+  { label: "fixed_base_score", render: (config) => (config.fixedBaseScore ?? null) === null ? "none" : String(config.fixedBaseScore) },
+  { label: "default_label_multiplier", render: (config) => (config.defaultLabelMultiplier ?? null) === null ? "none" : String(config.defaultLabelMultiplier) },
+  { label: "eligibility_mode", render: (config) => config.eligibilityMode ?? "default" },
+  /* v8 ignore next -- Boolean defaulting protects older registry snapshots without trusted_label_pipeline. */
+  { label: "trusted_label_pipeline", render: (config) => String(config.trustedLabelPipeline ?? false) },
+  { label: "label_multipliers", render: (config) => JSON.stringify(config.labelMultipliers) },
+];
+
+function registryConfigChanges(previous: RegistryRepoConfig, current: RegistryRepoConfig): string[] {
+  return REGISTRY_CHANGE_FIELDS.flatMap((field) => {
+    const before = field.render(previous);
+    const after = field.render(current);
+    if (before === after) return [];
+    // labelMultipliers is an object diff; report the fact of change, not the JSON blob.
+    return [field.label === "label_multipliers" ? "label_multipliers changed" : `${field.label} ${before} -> ${after}`];
+  });
+}
+
 export function buildRegistryChangeReport(snapshots: RegistrySnapshot[]): RegistryChangeReport {
   const [current, previous] = snapshots;
   if (!current) {
@@ -3048,14 +3076,7 @@ export function buildRegistryChangeReport(snapshots: RegistrySnapshot[]): Regist
     .flatMap(([repoFullName, repo]) => {
       const old = previousByRepo.get(repoFullName);
       if (!old) return [];
-      const changes = [
-        ...(repo.emissionShare !== old.emissionShare ? [`emission_share ${old.emissionShare} -> ${repo.emissionShare}`] : []),
-        ...(repo.issueDiscoveryShare !== old.issueDiscoveryShare ? [`issue_discovery_share ${old.issueDiscoveryShare} -> ${repo.issueDiscoveryShare}`] : []),
-        ...(repo.maintainerCut !== old.maintainerCut ? [`maintainer_cut ${old.maintainerCut} -> ${repo.maintainerCut}`] : []),
-        ...(JSON.stringify(repo.labelMultipliers) !== JSON.stringify(old.labelMultipliers) ? ["label_multipliers changed"] : []),
-        /* v8 ignore next -- Boolean defaulting protects older registry snapshots without trusted_label_pipeline. */
-        ...(repo.trustedLabelPipeline !== old.trustedLabelPipeline ? [`trusted_label_pipeline ${old.trustedLabelPipeline ?? false} -> ${repo.trustedLabelPipeline ?? false}`] : []),
-      ];
+      const changes = registryConfigChanges(old, repo);
       return changes.length > 0 ? [{ repoFullName, changes }] : [];
     })
     .sort((left, right) => left.repoFullName.localeCompare(right.repoFullName));

test/unit/signals-v2.test.ts

@@ -282,6 +282,25 @@ describe("v2 signal builders", () => {
     expect(report.changedRepos[0]?.changes).toContain("emission_share 0.01 -> 0.02");
   });
 
+  it("reports changes to fixed base score, default label multiplier, and eligibility mode", () => {
+    // Only fixedBaseScore changes; every other compared field is identical. The base
+    // score override is the highest-impact registry change, so it must be surfaced.
+    const previous = snapshot("old", [{ repo: "JSONbored/gittensory", emissionShare: 0.02, issueDiscoveryShare: 0, labelMultipliers: {}, fixedBaseScore: 2 }]);
+    const current = snapshot("new", [{ repo: "JSONbored/gittensory", emissionShare: 0.02, issueDiscoveryShare: 0, labelMultipliers: {}, fixedBaseScore: 50 }]);
+    const report = buildRegistryChangeReport([current, previous]);
+    expect(report.changedRepos).toHaveLength(1);
+    expect(report.changedRepos[0]?.changes).toContain("fixed_base_score 2 -> 50");
+    expect(report.summary).toContain("1 changed");
+
+    // eligibility_mode and default_label_multiplier are tracked too.
+    const beforeMode = snapshot("old2", [{ repo: "JSONbored/gittensory", emissionShare: 0.02, issueDiscoveryShare: 0, labelMultipliers: {}, eligibilityMode: "branch_required", defaultLabelMultiplier: 1 }]);
+    const afterMode = snapshot("new2", [{ repo: "JSONbored/gittensory", emissionShare: 0.02, issueDiscoveryShare: 0, labelMultipliers: {}, eligibilityMode: "any_branch", defaultLabelMultiplier: 1.2 }]);
+    const modeReport = buildRegistryChangeReport([afterMode, beforeMode]);
+    expect(modeReport.changedRepos[0]?.changes).toEqual(
+      expect.arrayContaining(["eligibility_mode branch_required -> any_branch", "default_label_multiplier 1 -> 1.2"]),
+    );
+  });
+
   it("builds repo-level maintainer packets with fallback actions", () => {
     const packet = buildMaintainerPacket(repo, [], [], repo.fullName);
     const busyPacket = buildMaintainerPacket(repo, issues, pullRequests, repo.fullName);
@@ -1518,7 +1537,18 @@ describe("v2 signal builders", () => {
   });
 });
 
-function snapshot(id: string, repositories: Array<{ repo: string; emissionShare: number; issueDiscoveryShare: number; labelMultipliers: Record<string, number> }>): RegistrySnapshot {
+function snapshot(
+  id: string,
+  repositories: Array<{
+    repo: string;
+    emissionShare: number;
+    issueDiscoveryShare: number;
+    labelMultipliers: Record<string, number>;
+    fixedBaseScore?: number | null;
+    defaultLabelMultiplier?: number | null;
+    eligibilityMode?: string | null;
+  }>,
+): RegistrySnapshot {
   return {
     id,
     generatedAt: "2026-05-23T00:00:00.000Z",