fix(ui): block usage export while the first activity page is loading

Also drop the explanatory comments the repo guidelines disallow.

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

ui/litellm-dashboard/src/app/(dashboard)/usage/_components/hooks/mergeDailyActivity.ts

@@ -74,14 +74,6 @@ const mergeDay = (a: DailyData, b: DailyData): DailyData => ({
   breakdown: mergeBreakdown(a.breakdown, b.breakdown),
 });
 
-/**
- * Combine daily activity pages into one series with a single entry per date.
- *
- * The backend paginates over raw spend rows, so a date whose rows straddle a
- * page boundary comes back once per page, each entry holding only that page's
- * share of the day. Concatenating those entries leaves duplicate dates that
- * under-report every per-day figure in the charts and the CSV export.
- */
 export const mergeDailyResults = (existing: readonly DailyData[], incoming: readonly DailyData[]): DailyData[] =>
   incoming.reduce<DailyData[]>(
     (acc, day) => {

ui/litellm-dashboard/src/app/(dashboard)/usage/_components/hooks/usePaginatedDailyActivity.test.ts

@@ -119,6 +119,24 @@ describe("usePaginatedDailyActivity", () => {
     expect(result.current.incomplete).toBe(false);
   });
 
+  it("stays incomplete while the first page is still in flight", async () => {
+    let resolveFirstPage: (value: ReturnType<typeof page>) => void = () => {};
+    const fetchFn = vi.fn().mockReturnValueOnce(
+      new Promise<ReturnType<typeof page>>((resolve) => {
+        resolveFirstPage = resolve;
+      }),
+    );
+
+    const { result } = renderHook(() => usePaginatedDailyActivity({ fetchFn, args, enabled: true }));
+
+    await waitFor(() => expect(result.current.loading).toBe(true), { timeout: 3000 });
+    expect(result.current.incomplete).toBe(true);
+
+    resolveFirstPage(page("2026-06-25", 22.38, 1, 1));
+
+    await waitFor(() => expect(result.current.incomplete).toBe(false), { timeout: 3000 });
+  });
+
   it("flags the range as incomplete when a page fetch fails instead of looking complete", async () => {
     const fetchFn = vi
       .fn()

ui/litellm-dashboard/src/app/(dashboard)/usage/_components/hooks/usePaginatedDailyActivity.ts

@@ -49,9 +49,7 @@ interface UsePaginatedDailyActivityReturn {
   isFetchingMore: boolean;
   progress: PaginationProgress;
   cancelled: boolean;
-  /** True when a page fetch failed, so the data on screen covers only part of the range. */
   failed: boolean;
-  /** True whenever the data on screen is known not to cover the whole requested range. */
   incomplete: boolean;
   cancel: () => void;
 }
@@ -250,7 +248,7 @@ export function usePaginatedDailyActivity({
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [enabled, fetchFn, argsKey]);
 
-  const incomplete = isFetchingMore || cancelled || failed;
+  const incomplete = loading || isFetchingMore || cancelled || failed;
 
   return { data, loading, isFetchingMore, progress, cancelled, failed, incomplete, cancel };
 }

ui/litellm-dashboard/src/components/EntityUsageExport/UsageExportHeader.tsx

@@ -34,7 +34,6 @@ interface UsageExportHeaderProps {
   customTitle?: string;
   compactLayout?: boolean;
   teams?: Team[];
-  /** Blocks the export while the data on screen does not cover the whole requested range. */
   exportDisabled?: boolean;
   exportDisabledReason?: string;
 }