refactor(ui): derive drilldown validity and drop Map mutation in bucket grouping

The drilldown now self-dismisses when refetched activity has no failures
for its call_type, instead of holding a selection the chart no longer
shows. groupErrorBuckets is rewritten as pure filter/map/sort over the
already-grouped SQL rows.

ui/litellm-dashboard/src/app/(dashboard)/caching/_components/ErrorDrilldown.tsx

@@ -24,21 +24,18 @@ export type ErrorCodeDatum = {
 };
 
 export const groupErrorBuckets = (buckets: readonly CacheActivityErrorBucket[], callType: string): ErrorCodeDatum[] => {
-  const byCode = new Map<string, Map<string, number>>();
-  for (const bucket of buckets) {
-    if (bucket.call_type !== callType) continue;
-    const classes = byCode.get(bucket.error_code) ?? new Map<string, number>();
-    classes.set(bucket.error_class, (classes.get(bucket.error_class) ?? 0) + bucket.count);
-    byCode.set(bucket.error_code, classes);
-  }
-  return [...byCode.entries()]
-    .map(([errorCode, classes]) => ({
-      error_code: errorCode,
-      [FAILED_REQUESTS_SERIES]: [...classes.values()].reduce((total, count) => total + count, 0),
-      classes: [...classes.entries()]
-        .map(([errorClass, count]) => ({ error_class: errorClass, count }))
-        .sort((a, b) => b.count - a.count),
-    }))
+  const rows = buckets.filter((bucket) => bucket.call_type === callType);
+  return [...new Set(rows.map((row) => row.error_code))]
+    .map((errorCode) => {
+      const codeRows = rows.filter((row) => row.error_code === errorCode);
+      return {
+        error_code: errorCode,
+        [FAILED_REQUESTS_SERIES]: codeRows.reduce((total, row) => total + row.count, 0),
+        classes: codeRows
+          .map((row) => ({ error_class: row.error_class, count: row.count }))
+          .sort((a, b) => b.count - a.count),
+      };
+    })
     .sort((a, b) => b[FAILED_REQUESTS_SERIES] - a[FAILED_REQUESTS_SERIES]);
 };
 

ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_dashboard.test.tsx

@@ -211,6 +211,31 @@ describe("CacheDashboard cache analytics charts", () => {
     expect(screen.queryByText(/Failed requests by error code/)).not.toBeInTheDocument();
   });
 
+  it("dismisses an open drilldown when refetched data no longer has failures for that call_type", async () => {
+    const { rerender } = renderDashboard();
+    const { requestsCard } = await findChartCards();
+
+    const redBar = Array.from(requestsCard.querySelectorAll(".recharts-bar")).find((bar) =>
+      bar.querySelector("path.recharts-rectangle")?.getAttribute("fill")?.includes("red"),
+    );
+    fireEvent.click(redBar!.querySelectorAll("path.recharts-rectangle")[0]);
+    expect(screen.getByText("Failed requests by error code: acompletion")).toBeInTheDocument();
+
+    useCacheActivity.mockReturnValue({
+      data: {
+        ...cacheActivity,
+        groups: cacheActivity.groups.map((group) =>
+          group.call_type === "acompletion" ? { ...group, failed_requests: 0 } : group,
+        ),
+        error_breakdown: cacheActivity.error_breakdown.filter((bucket) => bucket.call_type !== "acompletion"),
+      },
+      refetch: vi.fn(),
+    });
+    rerender(<CacheDashboard accessToken="sk-test" token="tok" userRole="Admin" userID="u1" premiumUser={false} />);
+
+    expect(screen.queryByText(/Failed requests by error code/)).not.toBeInTheDocument();
+  });
+
   it("formats y-axis ticks with compact notation", async () => {
     renderDashboard();
     const { requestsCard, tokensCard } = await findChartCards();

ui/litellm-dashboard/src/app/(dashboard)/caching/_components/cache_dashboard.tsx

@@ -49,6 +49,11 @@ const formatDateWithoutTZ = (date: Date | undefined) => {
   return date.toISOString().split("T")[0];
 };
 
+const resolveDrilldownCallType = (selected: string | null, groups: readonly CacheActivityGroup[]): string | null =>
+  selected !== null && groups.some((group) => group.call_type === selected && group.failed_requests > 0)
+    ? selected
+    : null;
+
 function valueFormatterNumbers(number: number) {
   const formatter = new Intl.NumberFormat("en-US", {
     maximumFractionDigits: 0,
@@ -98,6 +103,7 @@ const CacheDashboard: React.FC<CachePageProps> = ({ accessToken, token, userRole
   const uniqueApiKeys = activity?.filter_options.key_aliases ?? [];
   const uniqueModels = activity?.filter_options.models ?? [];
   const chartData = (activity?.groups ?? []).map(toChartDatum);
+  const activeDrilldownCallType = resolveDrilldownCallType(errorDrilldownCallType, activity?.groups ?? []);
 
   const handleRefreshClick = () => {
     refetch();
@@ -298,9 +304,9 @@ const CacheDashboard: React.FC<CachePageProps> = ({ accessToken, token, userRole
               </CardContent>
             </Card>
 
-            {errorDrilldownCallType !== null && (
+            {activeDrilldownCallType !== null && (
               <ErrorDrilldownCard
-                callType={errorDrilldownCallType}
+                callType={activeDrilldownCallType}
                 buckets={activity?.error_breakdown ?? []}
                 valueFormatter={valueFormatterNumbers}
                 onClose={() => setErrorDrilldownCallType(null)}