From e3d31bf178ae041c83f250aa607e7963ba022b70 Mon Sep 17 00:00:00 2001
From: Mike Allen <mike@tecarta.com>
Date: Sun, 4 Oct 2026 16:11:50 -0700
Subject: [PATCH 1/2] fix(ui_firestore): don't setState after dispose when
 fetching a page

_listenQuery delays its setState with a microtask so that fetchMore can be
called from a child's build. That build can be in the frame that removes the
FirestoreQueryBuilder (a list item scrolled away, a route torn down), so the
microtask runs after dispose and throws.
---
 .../lib/src/query_builder.dart                |  7 +++-
 .../test/query_builder_test.dart              | 38 +++++++++++++++++++
 2 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/packages/firebase_ui_firestore/lib/src/query_builder.dart b/packages/firebase_ui_firestore/lib/src/query_builder.dart
index 8511453a..15b4eef8 100644
--- a/packages/firebase_ui_firestore/lib/src/query_builder.dart
+++ b/packages/firebase_ui_firestore/lib/src/query_builder.dart
@@ -165,8 +165,11 @@ class _FirestoreQueryBuilderState<Document>
     }
 
     // Delaying the setState so that fetchNextpage can be used within a child's
-    // "build" – most commonly ListView's itemBuilder
-    Future.microtask(() => setState(() {}));
+    // "build" – most commonly ListView's itemBuilder. That build can be in the
+    // frame that removes this widget, so it may be gone by now.
+    Future.microtask(() {
+      if (mounted) setState(() {});
+    });
 
     final expectedDocsCount =
         (_pageCount + 1) * widget.pageSize
diff --git a/packages/firebase_ui_firestore/test/query_builder_test.dart b/packages/firebase_ui_firestore/test/query_builder_test.dart
index 8328bcfe..86b8692c 100644
--- a/packages/firebase_ui_firestore/test/query_builder_test.dart
+++ b/packages/firebase_ui_firestore/test/query_builder_test.dart
@@ -274,6 +274,44 @@ void main() {
     expect(snapshot.hasData, isTrue);
     expect(snapshot.isFetching, isFalse);
   });
+
+  testWidgets('scrolled away in the frame that its builder calls fetchMore', (
+    tester,
+  ) async {
+    final controller = ScrollController();
+    addTearDown(controller.dispose);
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: ListView(
+          controller: controller,
+          cacheExtent: 0,
+          itemExtent: 1000,
+          children: [
+            FirestoreQueryBuilder<Json>(
+              query: query,
+              pageSize: 2,
+              builder: (context, s, _) {
+                if (s.hasMore) s.fetchMore();
+                return const SizedBox();
+              },
+            ),
+            const SizedBox(),
+            const SizedBox(),
+          ],
+        ),
+      ),
+    );
+
+    // The snapshot rebuilds the query builder, whose builder fetches the
+    // next page, and the list drops it while laying out that same frame. The
+    // setState that fetchMore delays runs after it is disposed.
+    query.emit(3, size: 3, fromCache: false);
+    controller.jumpTo(2000);
+    await tester.pump();
+    expect(tester.takeException(), isNull);
+  });
 }
 
 class FakeQuery extends Fake implements Query<Json> {

From 7ffe1f702705995795b6d7b31572f0aec105079c Mon Sep 17 00:00:00 2001
From: Michael Allen <mike@tecarta.com>
Date: Sun, 4 Oct 2026 16:32:40 -0700
Subject: [PATCH 2/2] Apply suggestion from @gemini-code-assist[bot]

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 packages/firebase_ui_firestore/lib/src/query_builder.dart | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/firebase_ui_firestore/lib/src/query_builder.dart b/packages/firebase_ui_firestore/lib/src/query_builder.dart
index 15b4eef8..f574abc6 100644
--- a/packages/firebase_ui_firestore/lib/src/query_builder.dart
+++ b/packages/firebase_ui_firestore/lib/src/query_builder.dart
@@ -164,7 +164,7 @@ class _FirestoreQueryBuilderState<Document>
       _snapshot = _snapshot.copyWith(isFetching: true);
     }
 
-    // Delaying the setState so that fetchNextpage can be used within a child's
+    // Delaying the setState so that fetchMore can be used within a child's
     // "build" – most commonly ListView's itemBuilder. That build can be in the
     // frame that removes this widget, so it may be gone by now.
     Future.microtask(() {