fix(query-db): clean up empty ownership sets

.changeset/clean-query-ownership.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/query-db-collection': patch
+---
+
+Clean up empty query ownership state while preserving authoritative empty results and retained-row lifecycle behavior.

packages/query-db-collection/src/query.ts

@@ -737,7 +737,8 @@ export function queryCollectionOptions(
   // hashedQueryKey → queryKey
   const hashToQueryKey = new Map<string, QueryKey>()
 
-  // queryKey → Set<RowKey>
+  // queryKey → Set<RowKey>. Entry presence means ownership is resolved;
+  // an empty set represents a resolved query that currently owns no rows.
   const queryToRows = new Map<string, Set<string | number>>()
 
   // RowKey → Set<queryKey>
@@ -775,6 +776,11 @@ export function queryCollectionOptions(
   }
 
   const addRowOwners = (rowKey: string | number, owners: Set<string>) => {
+    if (owners.size === 0) {
+      rowToQueries.delete(rowKey)
+      return
+    }
+
     rowToQueries.set(rowKey, new Set(owners))
     owners.forEach((owner) => {
       const ownedRows = queryToRows.get(owner) || new Set<string | number>()
@@ -784,16 +790,16 @@ export function queryCollectionOptions(
   }
 
   const removeRowOwner = (rowKey: string | number, hashedQueryKey: string) => {
-    const owners = rowToQueries.get(rowKey) || new Set<string>()
-    owners.delete(hashedQueryKey)
-    rowToQueries.set(rowKey, owners)
+    const owners = rowToQueries.get(rowKey)
+    owners?.delete(hashedQueryKey)
+    if (!owners?.size) {
+      rowToQueries.delete(rowKey)
+    }
 
-    const ownedRows =
-      queryToRows.get(hashedQueryKey) || new Set<string | number>()
-    ownedRows.delete(rowKey)
-    queryToRows.set(hashedQueryKey, ownedRows)
+    const ownedRows = queryToRows.get(hashedQueryKey)
+    ownedRows?.delete(rowKey)
 
-    return owners.size === 0
+    return !owners?.size
   }
 
   const removeQueryOwnership = (hashedQueryKey: string) => {
@@ -1075,6 +1081,7 @@ export function queryCollectionOptions(
         `${QUERY_COLLECTION_GC_PREFIX}${hashedQueryKey}`,
       )
       commit()
+      queryToRows.delete(hashedQueryKey)
     }
 
     const schedulePersistedRetentionExpiry = (
@@ -1386,6 +1393,13 @@ export function queryCollectionOptions(
       const previouslyOwnedRows = shouldUsePersistedBaseline
         ? new Set(persistedBaseline.keys())
         : getHydratedOwnedRowsForQueryBaseline(hashedQueryKey)
+      // From this point onward the result, including an empty result, is the
+      // authoritative ownership baseline until this query is cleaned up.
+      queryToRows.set(
+        hashedQueryKey,
+        queryToRows.get(hashedQueryKey) ?? new Set<string | number>(),
+      )
+
       const newItemsMap = new Map<string | number, any>()
       newItemsArray.forEach((item) => {
         const key = getKey(item)
@@ -1746,7 +1760,10 @@ export function queryCollectionOptions(
       persistedRetentionTimers.clear()
 
       const allQueryKeys = [...hashToQueryKey.values()]
-      const allHashedKeys = [...state.observers.keys()]
+      const allHashedKeys = new Set([
+        ...state.observers.keys(),
+        ...queryToRows.keys(),
+      ])
 
       // Force cleanup all queries (explicit cleanup path)
       // This ignores hasListeners and always cleans up
@@ -2014,6 +2031,15 @@ export function queryCollectionOptions(
     }
   }
 
+  if (typeof process !== `undefined` && process.env.NODE_ENV === `test`) {
+    Object.defineProperty(enhancedInternalSync, `__getOwnershipMapsForTests`, {
+      value: () => ({
+        rowToQueries,
+        queryToRows,
+      }),
+    })
+  }
+
   // Create write utils using the manual-sync module
   const writeUtils = createWriteUtils<any, string | number, any>(
     () => writeContext,