fix: skip related plannings query when there are no events

__tests__/withPlannings.test.ts

@@ -0,0 +1,42 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import type { HitV1 } from '@ttab/elephant-api/index'
+import type { Session } from 'next-auth'
+import type { Index } from '@/shared/Index'
+
+const { fetchMock } = vi.hoisted(() => ({ fetchMock: vi.fn() }))
+
+vi.mock('@/hooks/index/useDocuments/lib/fetch', () => ({ fetch: fetchMock }))
+
+const { withPlannings } = await import('@/hooks/index/useDocuments/lib/withPlannings')
+
+const session = {} as Session
+const index = {} as unknown as Index
+const hit = (id: string): HitV1 => ({ id, fields: {} }) as unknown as HitV1
+
+describe('withPlannings', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('does not query the index when there are no events (avoids an empty-values terms query -> 500)', async () => {
+    const result = await withPlannings({ hits: [], session, index })
+
+    expect(fetchMock).not.toHaveBeenCalled()
+    expect(result).toEqual([])
+  })
+
+  it('queries related plannings with the event ids when events exist', async () => {
+    fetchMock.mockResolvedValue([])
+
+    await withPlannings({ hits: [hit('e1'), hit('e2')], session, index })
+
+    expect(fetchMock).toHaveBeenCalledTimes(1)
+
+    // The event ids must be passed as the terms `values`.
+    type TermsQuery = {
+      conditions: { bool: { must: Array<{ conditions: { terms: { values: string[] } } }> } }
+    }
+    const [arg] = fetchMock.mock.calls[0] as [{ query: TermsQuery }]
+    expect(arg.query.conditions.bool.must[0].conditions.terms.values).toEqual(['e1', 'e2'])
+  })
+})

src/hooks/index/useDocuments/lib/withPlannings.ts

@@ -13,7 +13,14 @@ export async function withPlannings<T extends HitV1>({ hits, session, index }: {
 }): Promise<T[]> {
   if (!session || !index) return hits
 
-  const eventIDs: string[] = hits.map((hit) => hit.id)
+  const eventIDs: string[] = hits.map((hit) => hit.id).filter(Boolean)
+
+  // No events means there are no related plannings to look up. Skip the query:
+  // a `terms` query with an empty `values` is serialized without `values` at
+  // all, which the index rejects with a 500 (seen on dates that have no events).
+  if (eventIDs.length === 0) {
+    return hits
+  }
 
   const plannings = await fetch<HitV1, withPlanningsFields>({
     documentType: 'core/planning-item',