Remove listeners from pending images when clearing cache (#107276)

Author: dnfield

packages/flutter/lib/src/painting/image_cache.dart

@@ -195,6 +195,9 @@ class ImageCache {
       image.dispose();
     }
     _cache.clear();
+    for (final _PendingImage pendingImage in _pendingImages.values) {
+      pendingImage.removeListener();
+    }
     _pendingImages.clear();
     _currentSizeBytes = 0;
   }

packages/flutter/test/painting/image_cache_test.dart

@@ -179,6 +179,10 @@ void main() {
       return completer1;
     })! as TestImageStreamCompleter;
 
+    // Make the image seem live.
+    final ImageStreamListener listener = ImageStreamListener((_, __) {});
+    completer1.addListener(listener);
+
     expect(imageCache.statusForKey(testImage).pending, true);
     expect(imageCache.statusForKey(testImage).live, true);
     imageCache.clear();
@@ -346,10 +350,10 @@ void main() {
 
     imageCache.clear();
     expect(imageCache.statusForKey(testImage1).pending, false);
-    expect(imageCache.statusForKey(testImage1).live, true);
+    expect(imageCache.statusForKey(testImage1).live, false);
 
     completer1.testSetImage(testImage1);
-    expect(imageCache.statusForKey(testImage1).keepAlive, true);
+    expect(imageCache.statusForKey(testImage1).keepAlive, false);
     expect(imageCache.statusForKey(testImage1).live, false);
 
     imageCache.putIfAbsent(testImage2, () => completer2);
@@ -602,4 +606,27 @@ void main() {
     imageInfo.dispose();
     expect(testImage.debugGetOpenHandleStackTraces()!.length, 0);
   }, skip: kIsWeb); // https://github.com/flutter/flutter/issues/87442
+
+  test('clear does not leave pending images stuck', () async {
+    final ui.Image testImage = await createTestImage(width: 8, height: 8);
+
+    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();
+
+    imageCache.putIfAbsent(testImage, () {
+      return completer1;
+    });
+
+    expect(imageCache.statusForKey(testImage).pending, true);
+    expect(imageCache.statusForKey(testImage).live, true);
+    expect(imageCache.statusForKey(testImage).keepAlive, false);
+
+    imageCache.clear();
+
+    // No one else is listening to the completer. It should not be considered
+    // live anymore.
+
+    expect(imageCache.statusForKey(testImage).pending, false);
+    expect(imageCache.statusForKey(testImage).live, false);
+    expect(imageCache.statusForKey(testImage).keepAlive, false);
+  });
 }