fix: manual transaction support in local-only collections

.changeset/metal-results-float.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/db': patch
+---
+
+Fixed `acceptMutations` not persisting data in local-only collections with manual transactions. The mutation filter was comparing against a stale `null` collection reference instead of using the collection ID, causing all mutations to be silently dropped after the transaction's `mutationFn` resolved.

packages/db/src/local-only.ts

@@ -179,7 +179,10 @@ export function localOnlyCollectionOptions<
 ): LocalOnlyCollectionOptionsResult<T, TKey, TSchema> & {
   schema?: StandardSchemaV1
 } {
-  const { initialData, onInsert, onUpdate, onDelete, ...restConfig } = config
+  const { initialData, onInsert, onUpdate, onDelete, id, ...restConfig } =
+    config
+
+  const collectionId = id ?? crypto.randomUUID()
 
   // Create the sync configuration with transaction confirmation capability
   const syncResult = createLocalOnlySync<T, TKey>(initialData)
@@ -247,9 +250,7 @@ export function localOnlyCollectionOptions<
   }) => {
     // Filter mutations that belong to this collection
     const collectionMutations = transaction.mutations.filter(
-      (m) =>
-        // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
-        m.collection === syncResult.collection,
+      (m) => m.collection.id === collectionId,
     )
 
     if (collectionMutations.length === 0) {
@@ -264,6 +265,7 @@ export function localOnlyCollectionOptions<
 
   return {
     ...restConfig,
+    id: collectionId,
     sync: syncResult.sync,
     onInsert: wrappedOnInsert,
     onUpdate: wrappedOnUpdate,

packages/db/tests/local-only.test.ts

@@ -481,7 +481,7 @@ describe(`LocalOnly Collection`, () => {
   })
 
   describe(`Manual transactions with acceptMutations`, () => {
-    it(`should accept and persist mutations from manual transactions`, () => {
+    it(`should accept and persist mutations from manual transactions`, async () => {
       const tx = createTransaction({
         mutationFn: async ({ transaction }: any) => {
           // Simulate API call success
@@ -510,6 +510,39 @@ describe(`LocalOnly Collection`, () => {
         id: 101,
         name: `Manual Tx Insert 2`,
       })
+
+      // Verify that the item is still present after async operations complete
+      await new Promise((resolve) => setTimeout(resolve, 1))
+      expect(collection.get(100)).toEqual({ id: 100, name: `Manual Tx Insert` })
+    })
+
+    it(`should work without explicit collection ID`, async () => {
+      // Create a collection without an explicit ID
+      const noIdCollection = createCollection<
+        TestItem,
+        number,
+        LocalOnlyCollectionUtils
+      >(
+        localOnlyCollectionOptions({
+          getKey: (item) => item.id,
+        }),
+      )
+
+      const tx = createTransaction({
+        mutationFn: async ({ transaction }: any) => {
+          noIdCollection.utils.acceptMutations(transaction)
+        },
+        autoCommit: false,
+      })
+
+      tx.mutate(() => {
+        noIdCollection.insert({ id: 999, name: `No ID Test` })
+      })
+
+      await tx.commit()
+
+      // Data should persist even without explicit ID
+      expect(noIdCollection.get(999)).toEqual({ id: 999, name: `No ID Test` })
     })
 
     it(`should only accept mutations for the specific collection`, () => {