Replace empty Container with const SizedBox (#108672)

packages/flutter/lib/src/cupertino/context_menu.dart

@@ -738,8 +738,8 @@ class _ContextMenuRoute<T> extends PopupRoute<T> {
     // buildTransitions as child, the idea being that buildTransitions will
     // animate the entire page into the scene. In the case of _ContextMenuRoute,
     // two individual pieces of the page are animated into the scene in
-    // buildTransitions, and a Container is returned here.
-    return Container();
+    // buildTransitions, and a SizedBox.shrink() is returned here.
+    return const SizedBox.shrink();
   }
 
   @override

packages/flutter/lib/src/cupertino/desktop_text_selection.dart

@@ -153,7 +153,7 @@ class _CupertinoDesktopTextSelectionControlsToolbarState extends State<_Cupertin
   Widget build(BuildContext context) {
     // Don't render the menu until the state of the clipboard is known.
     if (widget.handlePaste != null && widget.clipboardStatus?.value == ClipboardStatus.unknown) {
-      return const SizedBox(width: 0.0, height: 0.0);
+      return const SizedBox.shrink();
     }
 
     assert(debugCheckHasMediaQuery(context));
@@ -203,7 +203,7 @@ class _CupertinoDesktopTextSelectionControlsToolbarState extends State<_Cupertin
 
     // If there is no option available, build an empty widget.
     if (items.isEmpty) {
-      return const SizedBox(width: 0.0, height: 0.0);
+      return const SizedBox.shrink();
     }
 
     return _CupertinoDesktopTextSelectionToolbar(

packages/flutter/lib/src/cupertino/dialog.dart

@@ -1389,7 +1389,7 @@ class _CupertinoAlertContentSection extends StatelessWidget {
     if (title == null && message == null) {
       return SingleChildScrollView(
         controller: scrollController,
-        child: const SizedBox(width: 0.0, height: 0.0),
+        child: const SizedBox.shrink(),
       );
     }
 

packages/flutter/lib/src/cupertino/refresh.dart

@@ -422,7 +422,7 @@ class CupertinoSliverRefreshControl extends StatefulWidget {
         return CupertinoActivityIndicator(radius: radius * percentageComplete);
       case RefreshIndicatorMode.inactive:
         // Anything else doesn't show anything.
-        return Container();
+        return const SizedBox.shrink();
     }
   }
 

packages/flutter/lib/src/cupertino/tab_scaffold.dart

@@ -504,7 +504,7 @@ class _TabSwitchingViewState extends State<_TabSwitchingView> {
               child: FocusScope(
                 node: tabFocusNodes[index],
                 child: Builder(builder: (BuildContext context) {
-                  return shouldBuildTab[index] ? widget.tabBuilder(context, index) : Container();
+                  return shouldBuildTab[index] ? widget.tabBuilder(context, index) : const SizedBox.shrink();
                 }),
               ),
             ),

packages/flutter/lib/src/cupertino/text_selection.dart

@@ -82,7 +82,7 @@ class _CupertinoTextSelectionControlsToolbarState extends State<_CupertinoTextSe
   Widget build(BuildContext context) {
     // Don't render the menu until the state of the clipboard is known.
     if (widget.handlePaste != null && widget.clipboardStatus?.value == ClipboardStatus.unknown) {
-      return const SizedBox(width: 0.0, height: 0.0);
+      return const SizedBox.shrink();
     }
 
     assert(debugCheckHasMediaQuery(context));
@@ -147,7 +147,7 @@ class _CupertinoTextSelectionControlsToolbarState extends State<_CupertinoTextSe
 
     // If there is no option available, build an empty widget.
     if (items.isEmpty) {
-      return const SizedBox(width: 0.0, height: 0.0);
+      return const SizedBox.shrink();
     }
 
     return CupertinoTextSelectionToolbar(
@@ -266,7 +266,7 @@ class CupertinoTextSelectionControls extends TextSelectionControls {
         );
       // iOS doesn't draw anything for collapsed selections.
       case TextSelectionHandleType.collapsed:
-        return const SizedBox();
+        return const SizedBox.shrink();
     }
   }
 

packages/flutter/lib/src/material/about.dart

@@ -1451,7 +1451,7 @@ class _DetailView extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     if (_arguments == null) {
-      return Container();
+      return const SizedBox.shrink();
     }
     final double screenHeight = MediaQuery.of(context).size.height;
     final double minHeight = (screenHeight - kToolbarHeight) / screenHeight;

packages/flutter/lib/src/material/data_table.dart

@@ -237,7 +237,7 @@ class DataCell {
   }) : assert(child != null);
 
   /// A cell that has no content and has zero width and height.
-  static const DataCell empty = DataCell(SizedBox(width: 0.0, height: 0.0));
+  static const DataCell empty = DataCell(SizedBox.shrink());
 
   /// The data for the row.
   ///

packages/flutter/lib/src/material/desktop_text_selection.dart

@@ -153,7 +153,7 @@ class _DesktopTextSelectionControlsToolbarState extends State<_DesktopTextSelect
 
     // Don't render the menu until the state of the clipboard is known.
     if (widget.handlePaste != null && widget.clipboardStatus?.value == ClipboardStatus.unknown) {
-      return const SizedBox(width: 0.0, height: 0.0);
+      return const SizedBox.shrink();
     }
 
     final MediaQueryData mediaQuery = MediaQuery.of(context);
@@ -196,7 +196,7 @@ class _DesktopTextSelectionControlsToolbarState extends State<_DesktopTextSelect
 
     // If there is no option available, build an empty widget.
     if (items.isEmpty) {
-      return const SizedBox(width: 0.0, height: 0.0);
+      return const SizedBox.shrink();
     }
 
     return _DesktopTextSelectionToolbar(

packages/flutter/lib/src/material/dropdown.dart

@@ -1424,7 +1424,7 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
     // display the hint or nothing at all.
     final Widget innerItemsWidget;
     if (items.isEmpty) {
-      innerItemsWidget = Container();
+      innerItemsWidget = const SizedBox.shrink();
     } else {
       innerItemsWidget = IndexedStack(
         index: _selectedIndex ?? hintIndex,

packages/flutter/lib/src/material/ink_decoration.dart

@@ -292,7 +292,7 @@ class _InkState extends State<Ink> {
       _ink!.decoration = widget.decoration;
       _ink!.configuration = createLocalImageConfiguration(context);
     }
-    return widget.child ?? Container();
+    return widget.child ?? const SizedBox();
   }
 
   @override

packages/flutter/lib/src/material/input_decorator.dart

@@ -319,7 +319,7 @@ class _HelperError extends StatefulWidget {
 class _HelperErrorState extends State<_HelperError> with SingleTickerProviderStateMixin {
   // If the height of this widget and the counter are zero ("empty") at
   // layout time, no space is allocated for the subtext.
-  static const Widget empty = SizedBox();
+  static const Widget empty = SizedBox.shrink();
 
   late AnimationController _controller;
   Widget? _helper;

packages/flutter/lib/src/material/stepper.dart

@@ -641,7 +641,7 @@ class _StepperState extends State<Stepper> with TickerProviderStateMixin {
         child: widget.steps[index].label!,
       );
     }
-    return const SizedBox();
+    return const SizedBox.shrink();
   }
 
   Widget _buildVerticalHeader(int index) {

packages/flutter/lib/src/material/text_selection.dart

@@ -250,7 +250,7 @@ class _TextSelectionControlsToolbarState extends State<_TextSelectionControlsToo
 
     // If there is no option available, build an empty widget.
     if (itemDatas.isEmpty) {
-      return const SizedBox(width: 0.0, height: 0.0);
+      return const SizedBox.shrink();
     }
 
     return TextSelectionToolbar(

packages/flutter/lib/src/material/tooltip.dart

@@ -696,7 +696,7 @@ class TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
     // the empty black container so just return the wrapped child as is or
     // empty container if child is not specified.
     if (_tooltipMessage.isEmpty) {
-      return widget.child ?? const SizedBox();
+      return widget.child ?? const SizedBox.shrink();
     }
     assert(debugCheckHasOverlay(context));
     final ThemeData theme = Theme.of(context);

packages/flutter/lib/src/widgets/editable_text.dart

@@ -3829,10 +3829,10 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
       final int placeholderLocation = _value.text.length - _placeholderLocation;
       if (_isMultiline) {
         // The zero size placeholder here allows the line to break and keep the caret on the first line.
-        placeholders.add(const _ScribblePlaceholder(child: SizedBox(), size: Size.zero));
-        placeholders.add(_ScribblePlaceholder(child: const SizedBox(), size: Size(renderEditable.size.width, 0.0)));
+        placeholders.add(const _ScribblePlaceholder(child: SizedBox.shrink(), size: Size.zero));
+        placeholders.add(_ScribblePlaceholder(child: const SizedBox.shrink(), size: Size(renderEditable.size.width, 0.0)));
       } else {
-        placeholders.add(const _ScribblePlaceholder(child: SizedBox(), size: Size(100.0, 0.0)));
+        placeholders.add(const _ScribblePlaceholder(child: SizedBox.shrink(), size: Size(100.0, 0.0)));
       }
       return TextSpan(style: widget.style, children: <InlineSpan>[
           TextSpan(text: _value.text.substring(0, placeholderLocation)),

packages/flutter/lib/src/widgets/localizations.dart

@@ -6,7 +6,6 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/rendering.dart';
 
 import 'basic.dart';
-import 'container.dart';
 import 'debug.dart';
 import 'framework.dart';
 
@@ -598,7 +597,7 @@ class _LocalizationsState extends State<Localizations> {
   @override
   Widget build(BuildContext context) {
     if (_locale == null) {
-      return Container();
+      return const SizedBox.shrink();
     }
     return Semantics(
       textDirection: _textDirection,

packages/flutter/lib/src/widgets/text_selection.dart

@@ -1156,7 +1156,7 @@ class SelectionOverlay {
     final Widget handle;
     final TextSelectionControls? selectionControls = this.selectionControls;
     if (selectionControls == null) {
-      handle = Container();
+      handle = const SizedBox.shrink();
     } else {
       handle = _SelectionHandleOverlay(
         type: _startHandleType,
@@ -1183,7 +1183,7 @@ class SelectionOverlay {
     final TextSelectionControls? selectionControls = this.selectionControls;
     if (selectionControls == null || _startHandleType == TextSelectionHandleType.collapsed) {
       // Hide the second handle when collapsed.
-      handle = Container();
+      handle = const SizedBox.shrink();
     } else {
       handle = _SelectionHandleOverlay(
         type: _endHandleType,
@@ -1207,7 +1207,7 @@ class SelectionOverlay {
 
   Widget _buildToolbar(BuildContext context) {
     if (selectionControls == null) {
-      return Container();
+      return const SizedBox.shrink();
     }
 
     final RenderBox renderBox = this.context.findRenderObject()! as RenderBox;

packages/flutter/test/material/ink_paint_test.dart

@@ -9,14 +9,19 @@ import 'package:flutter_test/flutter_test.dart';
 import '../rendering/mock_canvas.dart';
 
 void main() {
-  testWidgets('The Ink widget renders a Container by default', (WidgetTester tester) async {
+  testWidgets('The Ink widget renders a SizedBox by default', (WidgetTester tester) async {
     await tester.pumpWidget(
       Material(
         child: Ink(),
       ),
     );
-    expect(tester.getSize(find.byType(Container)).height, 600.0);
-    expect(tester.getSize(find.byType(Container)).width, 800.0);
+    Finder sizedBox = find.descendant(
+      of: find.byType(Ink),
+      matching: find.byType(SizedBox),
+    );
+    expect(sizedBox, findsOneWidget);
+    expect(tester.getSize(sizedBox).height, 600.0);
+    expect(tester.getSize(sizedBox).width, 800.0);
 
     const double height = 150.0;
     const double width = 200.0;
@@ -31,8 +36,13 @@ void main() {
       ),
     );
     await tester.pumpAndSettle();
-    expect(tester.getSize(find.byType(Container)).height, height);
-    expect(tester.getSize(find.byType(Container)).width, width);
+    sizedBox = find.descendant(
+      of: find.byType(Ink),
+      matching: find.byType(SizedBox),
+    );
+    expect(sizedBox, findsNWidgets(2));
+    expect(tester.getSize(sizedBox.at(0)).height, height);
+    expect(tester.getSize(sizedBox.at(0)).width, width);
   });
 
   testWidgets('The InkWell widget renders an ink splash', (WidgetTester tester) async {