From 533a5dde96b35798c501811f3ba378b53bc4b7e4 Mon Sep 17 00:00:00 2001
From: Tomasz Gucio <72562119+tgucio@users.noreply.github.com>
Date: Thu, 24 Feb 2022 01:49:22 +0100
Subject: [PATCH] Call bringIntoView after RenderEditable updates on paste
 (#98604)

---
 .../lib/src/widgets/editable_text.dart        | 26 ++++++++--
 .../test/widgets/editable_text_test.dart      | 48 ++++++++++++++++++-
 2 files changed, 67 insertions(+), 7 deletions(-)

diff --git a/packages/flutter/lib/src/widgets/editable_text.dart b/packages/flutter/lib/src/widgets/editable_text.dart
index 99ae704991..7955af72c5 100644
--- a/packages/flutter/lib/src/widgets/editable_text.dart
+++ b/packages/flutter/lib/src/widgets/editable_text.dart
@@ -1689,7 +1689,10 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     Clipboard.setData(ClipboardData(text: selection.textInside(text)));
     _replaceText(ReplaceTextIntent(textEditingValue, '', selection, cause));
     if (cause == SelectionChangedCause.toolbar) {
-      bringIntoView(textEditingValue.selection.extent);
+      // Schedule a call to bringIntoView() after renderEditable updates.
+      SchedulerBinding.instance.addPostFrameCallback((_) {
+        bringIntoView(textEditingValue.selection.extent);
+      });
       hideToolbar();
     }
     _clipboardStatus?.update();
@@ -1715,7 +1718,10 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
 
     _replaceText(ReplaceTextIntent(textEditingValue, data.text!, selection, cause));
     if (cause == SelectionChangedCause.toolbar) {
-      bringIntoView(textEditingValue.selection.extent);
+      // Schedule a call to bringIntoView() after renderEditable updates.
+      SchedulerBinding.instance.addPostFrameCallback((_) {
+        bringIntoView(textEditingValue.selection.extent);
+      });
       hideToolbar();
     }
   }
@@ -3095,10 +3101,20 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   void _replaceText(ReplaceTextIntent intent) {
-    userUpdateTextEditingValue(
-      intent.currentTextEditingValue.replaced(intent.replacementRange, intent.replacementText),
-      intent.cause,
+    final TextEditingValue oldValue = _value;
+    final TextEditingValue newValue = intent.currentTextEditingValue.replaced(
+      intent.replacementRange,
+      intent.replacementText,
     );
+    userUpdateTextEditingValue(newValue, intent.cause);
+
+    // If there's no change in text and selection (e.g. when selecting and
+    // pasting identical text), the widget won't be rebuilt on value update.
+    // Handle this by calling _didChangeTextEditingValue() so caret and scroll
+    // updates can happen.
+    if (newValue == oldValue) {
+      _didChangeTextEditingValue();
+    }
   }
   late final Action<ReplaceTextIntent> _replaceTextAction = CallbackAction<ReplaceTextIntent>(onInvoke: _replaceText);
 
diff --git a/packages/flutter/test/widgets/editable_text_test.dart b/packages/flutter/test/widgets/editable_text_test.dart
index 5c7f821b38..f37aab5edb 100644
--- a/packages/flutter/test/widgets/editable_text_test.dart
+++ b/packages/flutter/test/widgets/editable_text_test.dart
@@ -10948,12 +10948,12 @@ void main() {
 
     // Paste
     await resetSelectionAndScrollOffset();
-    textSelectionDelegate.pasteText(SelectionChangedCause.keyboard);
+    await textSelectionDelegate.pasteText(SelectionChangedCause.keyboard);
     await tester.pump();
     expect(scrollController.offset, maxScrollExtent);
 
     await resetSelectionAndScrollOffset();
-    textSelectionDelegate.pasteText(SelectionChangedCause.toolbar);
+    await textSelectionDelegate.pasteText(SelectionChangedCause.toolbar);
     await tester.pump();
     expect(scrollController.offset.roundToDouble(), 0.0);
 
@@ -10980,6 +10980,50 @@ void main() {
     expect(scrollController.offset.roundToDouble(), 0.0);
   });
 
+  testWidgets('Should not scroll on paste if caret already visible', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/96658.
+    final ScrollController scrollController = ScrollController();
+    final TextEditingController controller = TextEditingController(
+      text: 'Lorem ipsum please paste here: \n${".\n" * 50}',
+    );
+    final FocusNode focusNode = FocusNode();
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Center(
+          child: SizedBox(
+            height: 600.0,
+            width: 600.0,
+            child: EditableText(
+              controller: controller,
+              scrollController: scrollController,
+              focusNode: focusNode,
+              maxLines: null,
+              style: const TextStyle(fontSize: 36.0),
+              backgroundCursorColor: Colors.grey,
+              cursorColor: cursorColor,
+            ),
+          ),
+        ),
+      )
+    );
+
+    await Clipboard.setData(const ClipboardData(text: 'Fairly long text to be pasted'));
+    focusNode.requestFocus();
+
+    final EditableTextState state =
+        tester.state<EditableTextState>(find.byType(EditableText));
+
+    expect(scrollController.offset, 0.0);
+
+    controller.selection = const TextSelection.collapsed(offset: 31);
+    await state.pasteText(SelectionChangedCause.toolbar);
+    await tester.pumpAndSettle();
+
+    // No scroll should happen as the caret is in the viewport all the time.
+    expect(scrollController.offset, 0.0);
+  });
+
   testWidgets('Autofill enabled by default', (WidgetTester tester) async {
     final FocusNode focusNode = FocusNode();
     await tester.pumpWidget(