fix(ui): let dialogs below StreamChat follow the app's brightness

packages/stream_chat_flutter/CHANGELOG.md

@@ -24,6 +24,7 @@
 - Fixed `StreamMessageComposer` polling the audio recorder ten times a second while no recording is in progress, including when voice recording is disabled.
 - Fixed `StreamMessageComposer`'s send button looking enabled on an empty message when voice recording is off, and showing the microphone instead of send for a staged poll.
 - Fixed the attachment picker showing an empty commands tab in channels without commands.
+- Fixed dialogs and bottom sheets opened below `StreamChat` keeping the old colors when the app switched between light and dark mode.
 
 ## 10.5.0
 

packages/stream_chat_flutter/lib/src/stream_chat.dart

@@ -217,8 +217,18 @@ class StreamChatState extends State<StreamChat> {
     final theme = widget.themeData ?? StreamChatThemeData();
     child = StreamChatTheme(data: theme, child: child);
 
-    final streamTheme = StreamTheme.of(context);
-    child = Theme(data: Theme.of(context).withExtension(streamTheme), child: child);
+    // Only when the app has not registered a StreamTheme itself: dialogs and
+    // sheets opened below this point copy the Theme once and would stop
+    // following the app's brightness (flutter/flutter#106642).
+    //
+    // The key keeps the subtree's state when the Theme comes or goes, such as
+    // when only one of the app's light and dark themes registers a StreamTheme.
+    child = KeyedSubtree(key: GlobalObjectKey(this), child: child);
+    final materialTheme = Theme.of(context);
+    if (materialTheme.extension<StreamTheme>() == null) {
+      final streamTheme = StreamTheme.of(context);
+      child = Theme(data: materialTheme.withExtension(streamTheme), child: child);
+    }
 
     if (widget.componentBuilders case final builders?) {
       child = StreamComponentFactory(builders: builders, child: child);

packages/stream_chat_flutter/test/src/stream_chat_test.dart

@@ -218,6 +218,79 @@ void main() {
         expect(captured, same(sibling));
       },
     );
+
+    testWidgets(
+      'a dialog opened below StreamChat follows the app theme when the '
+      'brightness changes',
+      (tester) async {
+        tester.platformDispatcher.platformBrightnessTestValue = Brightness.light;
+        addTearDown(tester.platformDispatcher.clearPlatformBrightnessTestValue);
+
+        final mockClient = MockClient();
+        final light = StreamTheme.light();
+        final dark = StreamTheme.dark();
+        StreamTheme? captured;
+
+        await tester.pumpWidget(
+          MaterialApp(
+            theme: ThemeData(extensions: [light]),
+            darkTheme: ThemeData(brightness: Brightness.dark, extensions: [dark]),
+            home: StreamChat(
+              client: mockClient,
+              child: Builder(
+                builder: (context) => TextButton(
+                  onPressed: () => showDialog<void>(
+                    context: context,
+                    builder: (context) {
+                      captured = Theme.of(context).extension<StreamTheme>();
+                      return const Text('Dialog');
+                    },
+                  ),
+                  child: const Text('Open'),
+                ),
+              ),
+            ),
+          ),
+        );
+
+        await tester.tap(find.text('Open'));
+        await tester.pumpAndSettle();
+        expect(captured, same(light));
+
+        tester.platformDispatcher.platformBrightnessTestValue = Brightness.dark;
+        await tester.pumpAndSettle();
+        expect(captured, same(dark));
+      },
+    );
+
+    testWidgets(
+      'keeps the state below StreamChat when only one of the app themes '
+      'registers a StreamTheme',
+      (tester) async {
+        tester.platformDispatcher.platformBrightnessTestValue = Brightness.light;
+        addTearDown(tester.platformDispatcher.clearPlatformBrightnessTestValue);
+
+        final mockClient = MockClient();
+
+        await tester.pumpWidget(
+          MaterialApp(
+            theme: ThemeData(extensions: [StreamTheme.light()]),
+            darkTheme: ThemeData(brightness: Brightness.dark),
+            home: StreamChat(
+              client: mockClient,
+              child: const Material(child: TextField()),
+            ),
+          ),
+        );
+
+        await tester.enterText(find.byType(TextField), 'draft');
+
+        tester.platformDispatcher.platformBrightnessTestValue = Brightness.dark;
+        await tester.pumpAndSettle();
+
+        expect(find.text('draft'), findsOneWidget);
+      },
+    );
   });
 }