fix(firestore): key document cache by Firestore instance, converter presence, and path

src/firestore.tsx

@@ -31,7 +31,7 @@ export async function preloadFirestoreDoc(refProvider: () => Promise<DocumentRef
 }
 
 function getDocObservableId<T = DocumentData>(ref: DocumentReference<T>) {
-  return `firestore:doc:${ref.firestore.app.name}:${ref.path}`;
+  return `firestore:doc:${getUniqueIdForFirestoreDoc(ref)}`;
 }
 
 /**
@@ -50,7 +50,7 @@ export function useFirestoreDoc<T = DocumentData>(ref: DocumentReference<T>, opt
  * Get a firestore document and don't subscribe to changes
  */
 export function useFirestoreDocOnce<T = DocumentData>(ref: DocumentReference<T>, options?: ReactFireOptions<T>): ObservableStatus<DocumentSnapshot<T>> {
-  const observableId = `firestore:docOnce:${ref.firestore.app.name}:${ref.path}`;
+  const observableId = `firestore:docOnce:${getUniqueIdForFirestoreDoc(ref)}`;
   const observable$ = doc(ref).pipe(first());
 
   return useObservable(observableId, observable$, options);
@@ -62,7 +62,7 @@ export function useFirestoreDocOnce<T = DocumentData>(ref: DocumentReference<T>,
 export function useFirestoreDocData<T = unknown>(ref: DocumentReference<T>, options?: ReactFireOptions<T>): ObservableStatus<T | undefined> {
   const idField = options ? checkIdField(options) : undefined;
 
-  const observableId = `firestore:docData:${ref.firestore.app.name}:${ref.path}:idField=${JSON.stringify(idField)}`;
+  const observableId = `firestore:docData:${getUniqueIdForFirestoreDoc(ref)}:idField=${JSON.stringify(idField)}`;
   const observable = docData(ref, { idField });
 
   return useObservable(observableId, observable, options) as ObservableStatus<T>;
@@ -74,7 +74,7 @@ export function useFirestoreDocData<T = unknown>(ref: DocumentReference<T>, opti
 export function useFirestoreDocDataOnce<T = unknown>(ref: DocumentReference<T>, options?: ReactFireOptions<T>): ObservableStatus<T | undefined> {
   const idField = options ? checkIdField(options) : undefined;
 
-  const observableId = `firestore:docDataOnce:${ref.firestore.app.name}:${ref.path}:idField=${JSON.stringify(idField)}`;
+  const observableId = `firestore:docDataOnce:${getUniqueIdForFirestoreDoc(ref)}:idField=${JSON.stringify(idField)}`;
   const observable$ = docData(ref, { idField }).pipe(first());
 
   return useObservable(observableId, observable$, options) as ObservableStatus<T>;
@@ -100,3 +100,25 @@ export function useFirestoreCollectionData<T = DocumentData>(query: FirestoreQue
 
   return useObservable(observableId, observable$, options);
 }
+
+// Small ids for Firestore instances (one per app and database), so refs to the same path in another database get
+// their own cache entry without scanning every ref seen so far. Kept on globalThis, like the query cache, so duplicate
+// copies of ReactFire hand out the same ids. Converters are keyed by presence, not identity: a converter object
+// created during render would otherwise change the key on every render.
+const docKeyIds: { ids: WeakMap<object, number>; next: number } = ((globalThis as any)._reactFireFirestoreDocKeyIds ??= {
+  ids: new WeakMap(),
+  next: 0,
+});
+
+function idFor(target: object): number {
+  let id = docKeyIds.ids.get(target);
+  if (id === undefined) {
+    id = docKeyIds.next++;
+    docKeyIds.ids.set(target, id);
+  }
+  return id;
+}
+
+function getUniqueIdForFirestoreDoc<T = DocumentData>(ref: DocumentReference<T>) {
+  return `${idFor(ref.firestore)}:${ref.converter ? 'converter' : 'raw'}:${ref.path}`;
+}

test/firestore.test.tsx

@@ -1,4 +1,4 @@
-import { renderHook, act, cleanup, waitFor } from '@testing-library/react';
+import { render, renderHook, act, cleanup, waitFor } from '@testing-library/react';
 
 import * as React from 'react';
 import '@testing-library/jest-dom/extend-expect';
@@ -17,7 +17,7 @@ import { baseConfig } from './appConfig';
 import { randomString } from './test-utils';
 
 import { addDoc, collection, doc, getFirestore, query, setDoc, connectFirestoreEmulator, where } from 'firebase/firestore';
-import type { DocumentReference } from 'firebase/firestore';
+import type { DocumentReference, FirestoreDataConverter } from 'firebase/firestore';
 
 describe('Firestore', () => {
   const app = initializeApp(baseConfig, 'firestore-test-suite');
@@ -352,5 +352,114 @@ describe('Firestore', () => {
 
       expect(result.current.data).toEqual([mockData]);
     });
+
+    it('separates cache entries for the same document path with and without a converter', async () => {
+      const colRef = collection(db, randomString());
+      const rawRef = doc(colRef, 'shared');
+      await setDoc(rawRef, { v: 7 });
+
+      const converter: FirestoreDataConverter<{ converted: boolean; v: number }> = {
+        toFirestore: (d) => ({ v: d.v }),
+        fromFirestore: (snap) => ({ converted: true, v: (snap.data() as { v: number }).v }),
+      };
+      const convertedRef = rawRef.withConverter(converter);
+
+      const RawDoc = () => {
+        const { data } = useFirestoreDocData(rawRef, { suspense: true });
+        return <div data-testid="raw">{JSON.stringify(data)}</div>;
+      };
+      const ConvertedDoc = () => {
+        const { data } = useFirestoreDocData(convertedRef, { suspense: true });
+        return <div data-testid="conv">{JSON.stringify(data)}</div>;
+      };
+
+      const { getByTestId } = render(
+        <Provider>
+          <React.Suspense fallback={<div data-testid="fb">loading</div>}>
+            <RawDoc />
+            <ConvertedDoc />
+          </React.Suspense>
+        </Provider>
+      );
+
+      await waitFor(() => expect(getByTestId('conv')).toBeInTheDocument());
+      expect(JSON.parse(getByTestId('conv').textContent || '{}').converted).toBe(true);
+    });
+
+    it('resolves when a converter object is created inline during render', async () => {
+      const colRef = collection(db, randomString());
+      await setDoc(doc(colRef, 'inline'), { name: 'alice' });
+
+      const makeConverter = (): FirestoreDataConverter<{ name: string }> => ({
+        toFirestore: (p) => p,
+        fromFirestore: (snap) => ({ name: String(snap.get('name')) }),
+      });
+
+      let statusRenders = 0;
+      const StatusProfile = () => {
+        statusRenders++;
+        const { status, data } = useFirestoreDocData(doc(colRef, 'inline').withConverter(makeConverter()));
+        return <div data-testid="status-out">{status === 'success' ? data?.name : 'loading'}</div>;
+      };
+
+      let suspenseRenders = 0;
+      const SuspenseProfile = () => {
+        suspenseRenders++;
+        const { data } = useFirestoreDocData(doc(colRef, 'inline').withConverter(makeConverter()), { suspense: true });
+        return <div data-testid="suspense-out">{data?.name}</div>;
+      };
+
+      const { getByTestId } = render(
+        <Provider>
+          <StatusProfile />
+          <React.Suspense fallback={<div data-testid="suspense-fb">fallback</div>}>
+            <SuspenseProfile />
+          </React.Suspense>
+        </Provider>
+      );
+
+      await waitFor(() => expect(getByTestId('status-out')).toHaveTextContent('alice'));
+      await waitFor(() => expect(getByTestId('suspense-out')).toHaveTextContent('alice'));
+      expect(statusRenders).toBeLessThan(10);
+      expect(suspenseRenders).toBeLessThan(10);
+    });
+
+    it('never shares a cache entry for different documents across two module instances', async () => {
+      const colRef = collection(db, randomString());
+      const x = doc(colRef, 'x');
+      const y = doc(colRef, 'y');
+      await setDoc(x, { v: 'x' });
+      await setDoc(y, { v: 'y' });
+
+      const copyA = await import('../src/index');
+      vi.resetModules();
+      const copyB = await import('../src/index');
+      expect(copyA.useFirestoreDocData).not.toBe(copyB.useFirestoreDocData);
+
+      const A = () => {
+        const { data } = copyA.useFirestoreDocData(x);
+        return <span data-testid="dual-a">{String((data as { v?: string })?.v)}</span>;
+      };
+      const B = () => {
+        const { data } = copyB.useFirestoreDocData(y);
+        return <span data-testid="dual-b">{String((data as { v?: string })?.v)}</span>;
+      };
+
+      const { getByTestId } = render(
+        <copyA.FirebaseAppProvider firebaseApp={app}>
+          <copyA.FirestoreProvider sdk={db}>
+            <A />
+          </copyA.FirestoreProvider>
+          <copyB.FirebaseAppProvider firebaseApp={app}>
+            <copyB.FirestoreProvider sdk={db}>
+              <B />
+            </copyB.FirestoreProvider>
+          </copyB.FirebaseAppProvider>
+        </copyA.FirebaseAppProvider>
+      );
+
+      await waitFor(() => expect(getByTestId('dual-a')).toHaveTextContent('x'));
+      await waitFor(() => expect(getByTestId('dual-b')).toHaveTextContent('y'));
+    });
   });
 });