fix(dashboard): preserve last-known PR enrichment when backfill fails

Poll cycles fully replaced the PR list each cycle, so a transient
enrichment-backfill failure (network blocker, blip, or GitHub hiccup)
wiped size/check-status data and reclassified dependency PRs from
Mergeable to Needs Action until the next successful poll.

Add fallbackToPreviousEnrichment to carry forward a PR's prior enriched
fields when the current cycle failed to re-enrich it, and guard the
fine-grained merge path against the same regression. Add warn + Sentry
telemetry to the backfill catch block to match its sibling fetchers.

Author: wgordon17

src/app/components/dashboard/DashboardPage.tsx

@@ -14,7 +14,7 @@ import DependenciesTab from "./DependenciesTab";
 import { isDependencyPr, expandBotLogins, needsBodyFallback, parseRenovateBody, type VersionInfo } from "../../lib/dependency-detection";
 import { isRepoExcludedFromDependencies } from "../../lib/dependency-exclusion";
 import { findDashboardIssues, parseAbandonedSection, resetAbandonedPatternCache, type AbandonedDependency } from "../../lib/dependency-dashboard";
-import { fetchDashboardIssueBodies, fetchDepPRBodies } from "../../services/api";
+import { fetchDashboardIssueBodies, fetchDepPRBodies, fallbackToPreviousEnrichment } from "../../services/api";
 import type { SortOption } from "../shared/SortDropdown";
 import type { Issue, PullRequest, WorkflowRun } from "../../services/api";
 import { fetchOrgs } from "../../services/api";
@@ -285,23 +285,29 @@ async function pollFetch(): Promise<DashboardData> {
           for (let i = 0; i < state.pullRequests.length; i++) {
             const e = enrichedMap.get(state.pullRequests[i].id)!;
             const pr = state.pullRequests[i];
-            pr.headSha = e.headSha;
-            pr.assigneeLogins = e.assigneeLogins;
-            pr.reviewerLogins = e.reviewerLogins;
-            pr.checkStatus = e.checkStatus;
-            pr.additions = e.additions;
-            pr.deletions = e.deletions;
-            pr.changedFiles = e.changedFiles;
-            pr.comments = e.comments;
-            pr.reviewThreads = e.reviewThreads;
-            pr.totalReviewCount = e.totalReviewCount;
-            pr.enriched = e.enriched;
+            // A failed backfill batch returns e.enriched === false for PRs it
+            // couldn't reach — don't let that regress a PR that was already
+            // enriched from a prior cycle.
+            const regressing = e.enriched === false && pr.enriched !== false;
+            if (!regressing) {
+              pr.headSha = e.headSha;
+              pr.assigneeLogins = e.assigneeLogins;
+              pr.reviewerLogins = e.reviewerLogins;
+              pr.checkStatus = e.checkStatus;
+              pr.additions = e.additions;
+              pr.deletions = e.deletions;
+              pr.changedFiles = e.changedFiles;
+              pr.comments = e.comments;
+              pr.reviewThreads = e.reviewThreads;
+              pr.totalReviewCount = e.totalReviewCount;
+              pr.enriched = e.enriched;
+            }
             pr.nodeId = e.nodeId;
             pr.surfacedBy = e.surfacedBy;
             pr.starCount = e.starCount;
           }
         } else {
-          state.pullRequests = data.pullRequests;
+          state.pullRequests = fallbackToPreviousEnrichment(state.pullRequests, data.pullRequests);
         }
       }));
     } else {
@@ -310,10 +316,11 @@ async function pollFetch(): Promise<DashboardData> {
       // changed since the last cycle. Preserve scroll position: SolidJS
       // DOM updates are synchronous within the setter, so save/restore
       // around it to prevent scroll reset from <For> DOM rebuild.
+      const pullRequests = fallbackToPreviousEnrichment(dashboardData.pullRequests, data.pullRequests);
       withScrollLock(() => {
         setDashboardData({
           issues: data.issues,
-          pullRequests: data.pullRequests,
+          pullRequests,
           workflowRuns: config.enableActions ? data.workflowRuns : [],
           loading: false,
           lastRefreshedAt: now,

src/app/services/api.ts

@@ -1151,6 +1151,8 @@ export async function fetchPREnrichment(
         updateGraphqlRateLimit(partialErr.rateLimit);
       }
       const { statusCode, message } = extractRejectionError(err);
+      console.warn(`[api] PR enrichment batch ${batchIdx + 1}/${batches.length} failed:`, err);
+      Sentry.captureException(err, { tags: { source: "prEnrichment" } });
       errors.push({
         repo: `backfill-batch-${batchIdx + 1}/${batches.length}`,
         statusCode, message,
@@ -1361,6 +1363,40 @@ function mergeEnrichment(
   });
 }
 
+/**
+ * Carries forward a PR's last-known enrichment when this cycle's backfill
+ * failed for it, instead of regressing an already-enriched PR to unenriched.
+ * Without this, a single transient backfill failure wipes size/check-status
+ * data and can flip dependency-status classification (e.g. Mergeable ->
+ * Needs Action) until the next successful poll re-enriches it.
+ */
+export function fallbackToPreviousEnrichment(
+  previous: PullRequest[],
+  next: PullRequest[]
+): PullRequest[] {
+  if (previous.length === 0) return next;
+  const previousMap = new Map(previous.map((pr) => [pr.id, pr]));
+  return next.map((pr) => {
+    if (pr.enriched !== false) return pr;
+    const prev = previousMap.get(pr.id);
+    if (!prev || prev.enriched === false) return pr;
+    return {
+      ...pr,
+      headSha: prev.headSha,
+      assigneeLogins: prev.assigneeLogins,
+      reviewerLogins: prev.reviewerLogins,
+      checkStatus: prev.checkStatus,
+      additions: prev.additions,
+      deletions: prev.deletions,
+      changedFiles: prev.changedFiles,
+      comments: prev.comments,
+      reviewThreads: prev.reviewThreads,
+      totalReviewCount: prev.totalReviewCount,
+      enriched: true,
+    };
+  });
+}
+
 /**
  * Merges tracked user search results into the main issue/PR maps.
  * Items already present get the tracked user's login appended to surfacedBy.