diff --git a/DEPS b/DEPS
index 1822c4d24bae1..34b4b850afaed 100644
--- a/DEPS
+++ b/DEPS
@@ -15,7 +15,7 @@ vars = {
   'flutter_git': 'https://flutter.googlesource.com',
   'skia_git': 'https://skia.googlesource.com',
   'llvm_git': 'https://llvm.googlesource.com',
-  'skia_revision': 'e61cc6d073fd3dd217b52e7b91d21151aad61478',
+  'skia_revision': 'deb0153719ddf8895c9c1448a9a6959610785947',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.
@@ -59,7 +59,7 @@ vars = {
   # updated revision list of existing dependencies. You will need to
   # gclient sync before and after update deps to ensure all deps are updated.
   # updated revision list of existing dependencies.
-  'dart_revision': '077062c5e5154cee4ffb1d72532428eaa79bc0fa',
+  'dart_revision': 'dbcb567e2432c7cf8401ca4d9365a3f040aa5deb',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
@@ -77,7 +77,7 @@ vars = {
   'dart_protobuf_rev': '9e30258e0aa6a6430ee36c84b75308a9702fde42',
   'dart_pub_rev': 'b297f1f5e42f2569f15a98548f44b4b9a48487c1',
   'dart_sync_http_rev': '6666fff944221891182e1f80bf56569338164d72',
-  'dart_tools_rev': 'd03c394b24829f662098e590a2c812a076b01199',
+  'dart_tools_rev': '97014f33a2aad59385df73f25baf9c304ca5c866',
   'dart_vector_math_rev': '70a9a2cb610d040b247f3ca2cd70a94c1c6f6f23',
   'dart_web_rev': '35fc98dd8f9da175ed0a2dcf246299e922e1e1e2',
   'dart_webdev_rev': '234e44c2ba0aa6cee5a36026538ca89457bf0d55',
@@ -810,7 +810,7 @@ deps = {
      'packages': [
        {
         'package': 'fuchsia/sdk/core/linux-amd64',
-        'version': 'u5vxWTRT0HlxOP5_rIPOkUJXTun41aPDWjrw0MQdakkC'
+        'version': 'QssSL8DkxIbMvf89CsxO9AsjjFWhqAZd7XoYRjQxeP8C'
        }
      ],
      'condition': 'download_fuchsia_deps and not download_fuchsia_sdk',
diff --git a/engine/src/flutter/fml/string_conversion.cc b/engine/src/flutter/fml/string_conversion.cc
index d55577c4e6471..e2f62c0fb117e 100644
--- a/engine/src/flutter/fml/string_conversion.cc
+++ b/engine/src/flutter/fml/string_conversion.cc
@@ -44,4 +44,9 @@ std::u16string Utf8ToUtf16(const std::string_view string) {
   return converter.from_bytes(string.data());
 }
 
+std::string PathToUtf8(const std::filesystem::path& path) {
+  const std::u8string path_u8 = path.u8string();
+  return std::string(path_u8.begin(), path_u8.end());
+}
+
 }  // namespace fml
diff --git a/engine/src/flutter/fml/string_conversion.h b/engine/src/flutter/fml/string_conversion.h
index eb7d840c3c717..48fb450a577d3 100644
--- a/engine/src/flutter/fml/string_conversion.h
+++ b/engine/src/flutter/fml/string_conversion.h
@@ -5,6 +5,7 @@
 #ifndef FLUTTER_FML_STRING_CONVERSION_H_
 #define FLUTTER_FML_STRING_CONVERSION_H_
 
+#include <filesystem>
 #include <string>
 #include <vector>
 
@@ -19,6 +20,9 @@ std::string Utf16ToUtf8(const std::u16string_view string);
 // Returns a UTF-16 encoded equivalent of a UTF-8 encoded input string.
 std::u16string Utf8ToUtf16(const std::string_view string);
 
+// Returns the pathname encoded in UTF-8.
+std::string PathToUtf8(const std::filesystem::path& path);
+
 }  // namespace fml
 
 #endif  // FLUTTER_FML_STRING_CONVERSION_H_
diff --git a/engine/src/flutter/fml/string_conversion_unittests.cc b/engine/src/flutter/fml/string_conversion_unittests.cc
index 4d12075709014..2369e4b39e6a9 100644
--- a/engine/src/flutter/fml/string_conversion_unittests.cc
+++ b/engine/src/flutter/fml/string_conversion_unittests.cc
@@ -33,5 +33,10 @@ TEST(StringConversion, Utf16ToUtf8Unicode) {
   EXPECT_EQ(Utf16ToUtf8(u"\x2603"), "\xe2\x98\x83");
 }
 
+TEST(StringConversion, PathToUtf8) {
+  EXPECT_EQ(PathToUtf8(std::filesystem::path("abc")), "abc");
+  EXPECT_EQ(PathToUtf8(std::filesystem::path(u"\x2603")), "\xe2\x98\x83");
+}
+
 }  // namespace testing
 }  // namespace fml
diff --git a/engine/src/flutter/impeller/display_list/aiks_dl_basic_unittests.cc b/engine/src/flutter/impeller/display_list/aiks_dl_basic_unittests.cc
index 303257008587b..004d47761b937 100644
--- a/engine/src/flutter/impeller/display_list/aiks_dl_basic_unittests.cc
+++ b/engine/src/flutter/impeller/display_list/aiks_dl_basic_unittests.cc
@@ -852,6 +852,25 @@ void RenderArcFarm(DisplayListBuilder& builder,
   }
   builder.Restore();
 }
+
+void RenderArcFarmForOverlappingCapsTest(DisplayListBuilder& builder,
+                                         const DlPaint& paint) {
+  builder.Save();
+  builder.Translate(40, 30);
+  const Rect arc_bounds = Rect::MakeLTRB(0, 0, 40, 40);
+  for (int stroke_width = 10; stroke_width <= 40; stroke_width += 3) {
+    DlPaint modified_paint = DlPaint(paint);
+    modified_paint.setStrokeWidth(stroke_width);
+    builder.Save();
+    for (int sweep = 160; sweep <= 360; sweep += 20) {
+      builder.DrawArc(arc_bounds, 0, sweep, false, modified_paint);
+      builder.Translate(84, 0);
+    }
+    builder.Restore();
+    builder.Translate(0, 44 + stroke_width);
+  }
+  builder.Restore();
+}
 }  // namespace
 
 TEST_P(AiksTest, FilledArcsRenderCorrectly) {
@@ -981,6 +1000,21 @@ TEST_P(AiksTest, StrokedArcsRenderCorrectlyWithSquareEnds) {
   ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
 }
 
+TEST_P(AiksTest, StrokedArcsRenderCorrectlyWithTranslucencyAndSquareEnds) {
+  DisplayListBuilder builder;
+  builder.Scale(GetContentScale().x, GetContentScale().y);
+  builder.DrawColor(DlColor::kWhite(), DlBlendMode::kSrc);
+
+  DlPaint paint;
+  paint.setDrawStyle(DlDrawStyle::kStroke);
+  paint.setStrokeCap(DlStrokeCap::kSquare);
+  paint.setColor(DlColor::kBlue().modulateOpacity(0.5));
+
+  RenderArcFarmForOverlappingCapsTest(builder, paint);
+
+  ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
+}
+
 TEST_P(AiksTest, StrokedArcsRenderCorrectlyWithRoundEnds) {
   DisplayListBuilder builder;
   builder.Scale(GetContentScale().x, GetContentScale().y);
@@ -1001,6 +1035,21 @@ TEST_P(AiksTest, StrokedArcsRenderCorrectlyWithRoundEnds) {
   ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
 }
 
+TEST_P(AiksTest, StrokedArcsRenderCorrectlyWithTranslucencyAndRoundEnds) {
+  DisplayListBuilder builder;
+  builder.Scale(GetContentScale().x, GetContentScale().y);
+  builder.DrawColor(DlColor::kWhite(), DlBlendMode::kSrc);
+
+  DlPaint paint;
+  paint.setDrawStyle(DlDrawStyle::kStroke);
+  paint.setStrokeCap(DlStrokeCap::kRound);
+  paint.setColor(DlColor::kBlue().modulateOpacity(0.5));
+
+  RenderArcFarmForOverlappingCapsTest(builder, paint);
+
+  ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
+}
+
 TEST_P(AiksTest, StrokedArcsRenderCorrectlyWithBevelJoinsAndCenter) {
   DisplayListBuilder builder;
   builder.Scale(GetContentScale().x, GetContentScale().y);
diff --git a/engine/src/flutter/impeller/entity/entity_unittests.cc b/engine/src/flutter/impeller/entity/entity_unittests.cc
index f6ccce5387f6b..580f9a753697b 100644
--- a/engine/src/flutter/impeller/entity/entity_unittests.cc
+++ b/engine/src/flutter/impeller/entity/entity_unittests.cc
@@ -2313,6 +2313,117 @@ TEST_P(EntityTest, FillPathGeometryGetPositionBufferReturnsExpectedMode) {
   }
 }
 
+TEST_P(EntityTest, StrokeArcGeometryGetPositionBufferReturnsExpectedMode) {
+  RenderTarget target;
+  testing::MockRenderPass mock_pass(GetContext(), target);
+  Rect oval_bounds = Rect::MakeLTRB(100, 100, 200, 200);
+
+  // Butt caps never overlap
+  {
+    StrokeParameters stroke = {.width = 50.0f, .cap = Cap::kButt};
+    for (auto start = 0; start < 360; start += 60) {
+      for (auto sweep = 0; sweep < 360; sweep += 12) {
+        auto geometry = Geometry::MakeStrokedArc(oval_bounds, Degrees(start),
+                                                 Degrees(sweep), stroke);
+
+        GeometryResult result =
+            geometry->GetPositionBuffer(*GetContentContext(), {}, mock_pass);
+
+        EXPECT_EQ(result.mode, GeometryResult::Mode::kNormal)
+            << "start: " << start << " sweep: " << sweep;
+      }
+    }
+  }
+
+  // Round caps with 10 stroke width overlap starting at 348.6 degrees
+  {
+    StrokeParameters stroke = {.width = 10.0f, .cap = Cap::kRound};
+    for (auto start = 0; start < 360; start += 60) {
+      for (auto sweep = 0; sweep < 360; sweep += 12) {
+        auto geometry = Geometry::MakeStrokedArc(oval_bounds, Degrees(start),
+                                                 Degrees(sweep), stroke);
+
+        GeometryResult result =
+            geometry->GetPositionBuffer(*GetContentContext(), {}, mock_pass);
+
+        if (sweep < 348.6) {
+          EXPECT_EQ(result.mode, GeometryResult::Mode::kNormal)
+              << "start: " << start << " sweep: " << sweep;
+        } else {
+          EXPECT_EQ(result.mode, GeometryResult::Mode::kPreventOverdraw)
+              << "start: " << start << " sweep: " << sweep;
+        }
+      }
+    }
+  }
+
+  // Round caps with 50 stroke width overlap starting at 300.1 degrees
+  {
+    StrokeParameters stroke = {.width = 50.0f, .cap = Cap::kRound};
+    for (auto start = 0; start < 360; start += 60) {
+      for (auto sweep = 0; sweep < 360; sweep += 12) {
+        auto geometry = Geometry::MakeStrokedArc(oval_bounds, Degrees(start),
+                                                 Degrees(sweep), stroke);
+
+        GeometryResult result =
+            geometry->GetPositionBuffer(*GetContentContext(), {}, mock_pass);
+
+        if (sweep < 300.0) {
+          EXPECT_EQ(result.mode, GeometryResult::Mode::kNormal)
+              << "start: " << start << " sweep: " << sweep;
+        } else {
+          EXPECT_EQ(result.mode, GeometryResult::Mode::kPreventOverdraw)
+              << "start: " << start << " sweep: " << sweep;
+        }
+      }
+    }
+  }
+
+  // Square caps with 10 stroke width overlap starting at 347.4 degrees
+  {
+    StrokeParameters stroke = {.width = 10.0f, .cap = Cap::kSquare};
+    for (auto start = 0; start < 360; start += 60) {
+      for (auto sweep = 0; sweep < 360; sweep += 12) {
+        auto geometry = Geometry::MakeStrokedArc(oval_bounds, Degrees(start),
+                                                 Degrees(sweep), stroke);
+
+        GeometryResult result =
+            geometry->GetPositionBuffer(*GetContentContext(), {}, mock_pass);
+
+        if (sweep < 347.4) {
+          EXPECT_EQ(result.mode, GeometryResult::Mode::kNormal)
+              << "start: " << start << " sweep: " << sweep;
+        } else {
+          EXPECT_EQ(result.mode, GeometryResult::Mode::kPreventOverdraw)
+              << "start: " << start << " sweep: " << sweep;
+        }
+      }
+    }
+  }
+
+  // Square caps with 50 stroke width overlap starting at 270.1 degrees
+  {
+    StrokeParameters stroke = {.width = 50.0f, .cap = Cap::kSquare};
+    for (auto start = 0; start < 360; start += 60) {
+      for (auto sweep = 0; sweep < 360; sweep += 12) {
+        auto geometry = Geometry::MakeStrokedArc(oval_bounds, Degrees(start),
+                                                 Degrees(sweep), stroke);
+
+        GeometryResult result =
+            geometry->GetPositionBuffer(*GetContentContext(), {}, mock_pass);
+
+        if (sweep < 270.1) {
+          EXPECT_EQ(result.mode, GeometryResult::Mode::kNormal)
+              << "start: " << start << " sweep: " << sweep;
+        } else {
+          EXPECT_EQ(result.mode, GeometryResult::Mode::kPreventOverdraw)
+              << "start: " << start << " sweep: " << sweep;
+        }
+      }
+    }
+  }
+}
+
 TEST_P(EntityTest, FailOnValidationError) {
   if (GetParam() != PlaygroundBackend::kVulkan) {
     GTEST_SKIP() << "Validation is only fatal on Vulkan backend.";
diff --git a/engine/src/flutter/impeller/entity/geometry/arc_geometry.cc b/engine/src/flutter/impeller/entity/geometry/arc_geometry.cc
index 056f7dacb6e11..926dda3035636 100644
--- a/engine/src/flutter/impeller/entity/geometry/arc_geometry.cc
+++ b/engine/src/flutter/impeller/entity/geometry/arc_geometry.cc
@@ -5,6 +5,7 @@
 #include "flutter/impeller/entity/geometry/arc_geometry.h"
 
 #include "flutter/impeller/entity/geometry/line_geometry.h"
+#include "fml/logging.h"
 
 namespace impeller {
 
@@ -47,7 +48,11 @@ GeometryResult ArcGeometry::GetPositionBuffer(const ContentContext& renderer,
     auto generator =
         renderer.GetTessellator().StrokedArc(transform, arc_, cap_, half_width);
 
-    return ComputePositionGeometry(renderer, generator, entity, pass);
+    auto result = ComputePositionGeometry(renderer, generator, entity, pass);
+    if (CapsOverlap()) {
+      result.mode = GeometryResult::Mode::kPreventOverdraw;
+    }
+    return result;
   }
 }
 
@@ -80,4 +85,53 @@ bool ArcGeometry::IsAxisAlignedRect() const {
   return false;
 }
 
+bool ArcGeometry::CapsOverlap() const {
+  FML_DCHECK(arc_.GetSweep().degrees >= 0.0f);
+  FML_DCHECK(arc_.GetSweep().degrees <= 360.0f);
+
+  if (stroke_width_ < 0 || cap_ == Cap::kButt ||
+      arc_.GetSweep().degrees <= 180) {
+    return false;
+  }
+
+  switch (cap_) {
+    case Cap::kSquare: {
+      // Square caps overlap if the inner corner of the ending cap extends
+      // inside the inner edge of the start cap. For a visualization of when
+      // this occurs, see
+      // https://github.com/flutter/flutter/issues/178746#issuecomment-3554526727
+      // Note that testing for overlap is completely independent of the arc's
+      // start angle. To simplify the overlap test, we treat the arc as if its
+      // start angle is 0. This allows the test to only require checking the x
+      // coordinate of the ending cap, rather than needing to calculate overlap
+      // based on both x and y positions of both caps.
+      auto radius = arc_.GetOvalSize().width * 0.5f;
+      auto half_width = stroke_width_ * 0.5f;
+      auto inner_radius = radius - half_width;
+      auto inner_arc_end_x =
+          cos(Radians(arc_.GetSweep()).radians) * inner_radius;
+      auto inner_square_cap_end_x =
+          inner_arc_end_x +
+          cos(Radians(arc_.GetSweep() + Degrees(90)).radians) * half_width;
+      return inner_square_cap_end_x > inner_radius;
+    }
+    case Cap::kRound: {
+      // Round caps overlap if the distance between the arc's start and end
+      // points is less than the stroke width.
+      // https://github.com/flutter/flutter/issues/178746#issuecomment-3554526727
+      // Note that testing for overlap is completely independent of the arc's
+      // start angle. To simplify the overlap test, we treat the arc as if its
+      // start angle is 0.
+      auto radius = arc_.GetOvalSize().width / 2.0f;
+      auto start_point = Point(radius, 0);
+      auto sweep_radians = Radians(arc_.GetSweep()).radians;
+      auto end_point = Point(cos(sweep_radians), sin(sweep_radians)) * radius;
+      return start_point.GetDistanceSquared(end_point) <
+             stroke_width_ * stroke_width_;
+    }
+    case Cap::kButt:
+      FML_UNREACHABLE()
+  }
+}
+
 }  // namespace impeller
diff --git a/engine/src/flutter/impeller/entity/geometry/arc_geometry.h b/engine/src/flutter/impeller/entity/geometry/arc_geometry.h
index 4657b2ce9fba0..f1b02d6d027f3 100644
--- a/engine/src/flutter/impeller/entity/geometry/arc_geometry.h
+++ b/engine/src/flutter/impeller/entity/geometry/arc_geometry.h
@@ -40,6 +40,9 @@ class ArcGeometry final : public Geometry {
   // |Geometry|
   std::optional<Rect> GetCoverage(const Matrix& transform) const override;
 
+  // Whether the arc has overlapping stroke caps
+  bool CapsOverlap() const;
+
   Arc arc_;
   Scalar stroke_width_;
   Cap cap_;
diff --git a/engine/src/flutter/shell/platform/windows/flutter_project_bundle.cc b/engine/src/flutter/shell/platform/windows/flutter_project_bundle.cc
index b63dad588a551..f2fc0be8756d0 100644
--- a/engine/src/flutter/shell/platform/windows/flutter_project_bundle.cc
+++ b/engine/src/flutter/shell/platform/windows/flutter_project_bundle.cc
@@ -7,6 +7,7 @@
 #include <filesystem>
 
 #include "flutter/fml/logging.h"
+#include "flutter/fml/string_conversion.h"
 #include "flutter/shell/platform/common/engine_switches.h"  // nogncheck
 #include "flutter/shell/platform/common/path_utils.h"
 
@@ -73,7 +74,7 @@ UniqueAotDataPtr FlutterProjectBundle::LoadAotData(
                    << "; no such file.";
     return UniqueAotDataPtr(nullptr, nullptr);
   }
-  std::string path_string = aot_library_path_.string();
+  std::string path_string = fml::PathToUtf8(aot_library_path_);
   FlutterEngineAOTDataSource source = {};
   source.type = kFlutterEngineAOTDataSourceTypeElfPath;
   source.elf_path = path_string.c_str();
diff --git a/engine/src/flutter/shell/platform/windows/flutter_windows_engine.cc b/engine/src/flutter/shell/platform/windows/flutter_windows_engine.cc
index d579c818ecfa3..70d7364d56e64 100644
--- a/engine/src/flutter/shell/platform/windows/flutter_windows_engine.cc
+++ b/engine/src/flutter/shell/platform/windows/flutter_windows_engine.cc
@@ -274,8 +274,8 @@ bool FlutterWindowsEngine::Run(std::string_view entrypoint) {
     FML_LOG(ERROR) << "Missing or unresolvable paths to assets.";
     return false;
   }
-  std::string assets_path_string = project_->assets_path().string();
-  std::string icu_path_string = project_->icu_path().string();
+  std::string assets_path_string = fml::PathToUtf8(project_->assets_path());
+  std::string icu_path_string = fml::PathToUtf8(project_->icu_path());
   if (embedder_api_.RunsAOTCompiledDartCode()) {
     aot_data_ = project_->LoadAotData(embedder_api_);
     if (!aot_data_) {
diff --git a/engine/src/flutter/tools/templater/templater_main.cc b/engine/src/flutter/tools/templater/templater_main.cc
index c803d7290b9af..0bff26e581237 100644
--- a/engine/src/flutter/tools/templater/templater_main.cc
+++ b/engine/src/flutter/tools/templater/templater_main.cc
@@ -12,6 +12,7 @@
 #include "flutter/fml/file.h"
 #include "flutter/fml/logging.h"
 #include "flutter/fml/mapping.h"
+#include "flutter/fml/string_conversion.h"
 #include "inja/inja.hpp"
 
 namespace flutter {
@@ -50,9 +51,9 @@ bool TemplaterMain(const fml::CommandLine& command_line) {
       reinterpret_cast<const uint8_t*>(rendered_template.data()),
       rendered_template.size()};
 
-  auto current_dir =
-      fml::OpenDirectory(std::filesystem::current_path().string().c_str(),
-                         false, fml::FilePermission::kReadWrite);
+  auto current_dir = fml::OpenDirectory(
+      fml::PathToUtf8(std::filesystem::current_path()).c_str(), false,
+      fml::FilePermission::kReadWrite);
   if (!current_dir.is_valid()) {
     FML_LOG(ERROR) << "Could not open current directory.";
     return false;
diff --git a/examples/api/lib/widgets/routes/route_observer.0.dart b/examples/api/lib/widgets/routes/route_observer.0.dart
index fdb44fdce451c..e1ce6adc72eff 100644
--- a/examples/api/lib/widgets/routes/route_observer.0.dart
+++ b/examples/api/lib/widgets/routes/route_observer.0.dart
@@ -63,37 +63,39 @@ class _RouteObserverExampleState extends State<RouteObserverExample>
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      body: Center(
-        child: Column(
-          mainAxisSize: MainAxisSize.min,
-          children: <Widget>[
-            Text(
-              'RouteObserver log:',
-              style: Theme.of(context).textTheme.headlineSmall,
-            ),
-            ConstrainedBox(
-              constraints: const BoxConstraints(maxHeight: 300.0),
-              child: ListView.builder(
-                itemCount: log.length,
-                itemBuilder: (BuildContext context, int index) {
-                  if (log.isEmpty) {
-                    return const SizedBox.shrink();
-                  }
-                  return Text(log[index], textAlign: TextAlign.center);
+      body: SingleChildScrollView(
+        child: Center(
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: <Widget>[
+              Text(
+                'RouteObserver log:',
+                style: Theme.of(context).textTheme.headlineSmall,
+              ),
+              ConstrainedBox(
+                constraints: const BoxConstraints(maxHeight: 300.0),
+                child: ListView.builder(
+                  itemCount: log.length,
+                  itemBuilder: (BuildContext context, int index) {
+                    if (log.isEmpty) {
+                      return const SizedBox.shrink();
+                    }
+                    return Text(log[index], textAlign: TextAlign.center);
+                  },
+                ),
+              ),
+              OutlinedButton(
+                onPressed: () {
+                  Navigator.of(context).push<void>(
+                    MaterialPageRoute<void>(
+                      builder: (BuildContext context) => const NextPage(),
+                    ),
+                  );
                 },
+                child: const Text('Go to next page'),
               ),
-            ),
-            OutlinedButton(
-              onPressed: () {
-                Navigator.of(context).push<void>(
-                  MaterialPageRoute<void>(
-                    builder: (BuildContext context) => const NextPage(),
-                  ),
-                );
-              },
-              child: const Text('Go to next page'),
-            ),
-          ],
+            ],
+          ),
         ),
       ),
     );
diff --git a/examples/api/test/widgets/routes/route_observer.0_test.dart b/examples/api/test/widgets/routes/route_observer.0_test.dart
index 3c79c47639837..91e60952e3a07 100644
--- a/examples/api/test/widgets/routes/route_observer.0_test.dart
+++ b/examples/api/test/widgets/routes/route_observer.0_test.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/rendering.dart';
 import 'package:flutter_api_samples/widgets/routes/route_observer.0.dart'
     as example;
 import 'package:flutter_test/flutter_test.dart';
@@ -38,5 +39,24 @@ void main() {
     // Check the RouteObserver logs after the route is popped again.
     expect(find.text('didPush'), findsOneWidget);
     expect(find.text('didPopNext'), findsNWidgets(2));
+
+    // Check if any overflow or layout exceptions occurred.
+    expect(tester.takeException(), isNull);
   });
+
+  testWidgets(
+    'RouteObserver example renders without overflow on small screens',
+    (WidgetTester tester) async {
+      // Set the screen size to a smaller value.
+      tester.view.physicalSize = const Size(200, 200);
+      addTearDown(tester.view.reset);
+
+      // Build the RouteObserver example widget.
+      await tester.pumpWidget(const example.RouteObserverApp());
+      await tester.pumpAndSettle();
+
+      // Verify there are no layout exceptions.
+      expect(tester.takeException(), isNull);
+    },
+  );
 }
diff --git a/packages/flutter/lib/src/material/bottom_sheet.dart b/packages/flutter/lib/src/material/bottom_sheet.dart
index 00fa0ec6db4f7..77c042db4c06c 100644
--- a/packages/flutter/lib/src/material/bottom_sheet.dart
+++ b/packages/flutter/lib/src/material/bottom_sheet.dart
@@ -6,6 +6,7 @@
 library;
 
 import 'dart:math' as math;
+import 'dart:ui' show SemanticsHitTestBehavior;
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
@@ -1117,10 +1118,13 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
       ),
     );
 
-    final Widget bottomSheet = useSafeArea
+    Widget bottomSheet = useSafeArea
         ? SafeArea(bottom: false, child: content)
         : MediaQuery.removePadding(context: context, removeTop: true, child: content);
 
+    // Prevent clicks inside the bottom sheet from passing through to the barrier
+    bottomSheet = Semantics(hitTestBehavior: SemanticsHitTestBehavior.opaque, child: bottomSheet);
+
     return capturedThemes?.wrap(bottomSheet) ?? bottomSheet;
   }
 
diff --git a/packages/flutter/lib/src/material/carousel.dart b/packages/flutter/lib/src/material/carousel.dart
index 24f74cee40944..54f032ccbcdbb 100644
--- a/packages/flutter/lib/src/material/carousel.dart
+++ b/packages/flutter/lib/src/material/carousel.dart
@@ -455,21 +455,10 @@ class CarouselView extends StatefulWidget {
   /// {@template flutter.material.CarouselView.onIndexChanged}
   /// A callback invoked when the leading item changes.
   ///
-  /// The “leading” item is the one that the carousel resolves as primary for
-  /// the current frame according to its layout algorithm. This item can be only
-  /// partially visible while scrolling.
+  /// For both [CarouselView] and [CarouselView.weighted], the leading item is
+  /// the first visible item in the carousel view.
   ///
-  /// - In a standard [CarouselView], the leading item is the one positioned at
-  ///   the leading edge of the viewport based on the current scroll offset.
-  ///
-  /// - In a [CarouselView.weighted], the leading item is chosen by the weighted
-  ///   layout algorithm (typically the one with the greatest effective weight;
-  ///   ties are resolved using proximity to the leading edge).
-  ///
-  /// If `itemSnapping` is enabled, scrolling settles with the resolved leading
-  /// item fully visible when possible.
-  ///
-  /// The callback fires only when the resolved leading index actually changes,
+  /// The callback fires only when the leading index actually changes,
   /// whether due to user interaction or programmatic scrolling.
   /// {@endtemplate}
   ///
@@ -564,11 +553,15 @@ class _CarouselViewState extends State<CarouselView> {
     super.dispose();
   }
 
+  // The initialItem means the index of the item to occupy the first maximum weight
+  // when flexWeights is not null. So it might be negative when initialItem value
+  // is small but the first max weight index is large. In that case, the initial
+  // leading item should be 0.
   int _getInitialLeadingItem() {
     if (widget.flexWeights != null) {
       final int maxWeight = widget.flexWeights!.max;
       final int firstMaxWeightIndex = widget.flexWeights!.indexOf(maxWeight);
-      return _controller.initialItem - firstMaxWeightIndex;
+      return math.max(_controller.initialItem - firstMaxWeightIndex, 0);
     }
     return _controller.initialItem;
   }
@@ -1637,10 +1630,25 @@ class _CarouselPosition extends ScrollPositionWithSingleContext implements _Caro
   }
 
   // The index of the leading item in the carousel.
-  // getItemFromPixels may return a fractional value (e.g., 0.6 when mid-scroll).
-  // We use toInt() to truncate the fractional part, ensuring the leading item
+  // `getItemFromPixels` may return a fractional value (e.g., 0.6 when mid-scroll).
+  // Use `toInt()` to truncate the fractional part, ensuring the leading item
   // only advances after fully crossing the next item's boundary.
-  int get leadingItem => getItemFromPixels(pixels, viewportDimension).toInt();
+  int get leadingItem {
+    final int leadingItem = getItemFromPixels(pixels, viewportDimension).toInt();
+    // When `consumeMaxWeight` is true, there is some reserved space before
+    // item 0 so that item 0 can be expanded to occupy the maximum
+    // weight while scrolling. The way how consumeMaxWeight works is that we assume
+    // there are some "invisible" items before the first visible item. Therefore,
+    // to calculate the correct visible leading item, we need to offset the leading
+    // item by the index of the maximum weight.
+    //
+    // The subtraction may cause negative number for leading item. In this case,
+    // constrain the leading item to 0.
+    if (consumeMaxWeight && flexWeights != null) {
+      return math.max(leadingItem - flexWeights!.indexOf(flexWeights!.max), 0);
+    }
+    return leadingItem;
+  }
 
   double updateLeadingItem(List<int>? newFlexWeights, bool newConsumeMaxWeight) {
     final double maxItem;
diff --git a/packages/flutter/lib/src/material/dialog.dart b/packages/flutter/lib/src/material/dialog.dart
index 78d1369e3a5f0..e4c6d2e8017c6 100644
--- a/packages/flutter/lib/src/material/dialog.dart
+++ b/packages/flutter/lib/src/material/dialog.dart
@@ -10,7 +10,7 @@
 /// @docImport 'text_button.dart';
 library;
 
-import 'dart:ui' show SemanticsRole, clampDouble, lerpDouble;
+import 'dart:ui' show SemanticsHitTestBehavior, SemanticsRole, clampDouble, lerpDouble;
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
@@ -1676,6 +1676,8 @@ class DialogRoute<T> extends RawDialogRoute<T> {
                if (useSafeArea) {
                  dialog = SafeArea(child: dialog);
                }
+               // Prevent clicks inside the dialog from passing through to the barrier
+               dialog = Semantics(hitTestBehavior: SemanticsHitTestBehavior.opaque, child: dialog);
                return dialog;
              },
          barrierLabel: barrierLabel ?? MaterialLocalizations.of(context).modalBarrierDismissLabel,
diff --git a/packages/flutter/lib/src/rendering/custom_paint.dart b/packages/flutter/lib/src/rendering/custom_paint.dart
index 298a34532baf9..d10dfe738a325 100644
--- a/packages/flutter/lib/src/rendering/custom_paint.dart
+++ b/packages/flutter/lib/src/rendering/custom_paint.dart
@@ -1043,6 +1043,9 @@ class RenderCustomPaint extends RenderProxyBox {
     if (config.validationResult != properties.validationResult) {
       config.validationResult = properties.validationResult;
     }
+    if (properties.hitTestBehavior != null) {
+      config.hitTestBehavior = properties.hitTestBehavior!;
+    }
     if (properties.inputType != null) {
       config.inputType = properties.inputType!;
     }
diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
index b5c39afa12f9f..15da70fd1af07 100644
--- a/packages/flutter/lib/src/rendering/object.dart
+++ b/packages/flutter/lib/src/rendering/object.dart
@@ -4938,6 +4938,10 @@ mixin SemanticsAnnotationsMixin on RenderObject {
       config.validationResult = _properties.validationResult;
     }
 
+    if (_properties.hitTestBehavior != null) {
+      config.hitTestBehavior = _properties.hitTestBehavior!;
+    }
+
     if (_properties.inputType != null) {
       config.inputType = _properties.inputType!;
     }
diff --git a/packages/flutter/lib/src/rendering/platform_view.dart b/packages/flutter/lib/src/rendering/platform_view.dart
index ca833e3f2a34f..e2830e97f0c33 100644
--- a/packages/flutter/lib/src/rendering/platform_view.dart
+++ b/packages/flutter/lib/src/rendering/platform_view.dart
@@ -5,6 +5,8 @@
 /// @docImport 'package:flutter/widgets.dart';
 library;
 
+import 'dart:ui' as ui show SemanticsHitTestBehavior;
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/scheduler.dart';
@@ -267,6 +269,9 @@ class RenderAndroidView extends PlatformViewRenderBox {
 
     if (_viewController.isCreated) {
       config.platformViewId = _viewController.viewId;
+      // Platform views should allow pointer events to pass through to the
+      // underlying platform view content.
+      config.hitTestBehavior = ui.SemanticsHitTestBehavior.transparent;
     }
   }
 }
@@ -372,6 +377,9 @@ abstract class RenderDarwinPlatformView<T extends DarwinPlatformViewController>
     super.describeSemanticsConfiguration(config);
     config.isSemanticBoundary = true;
     config.platformViewId = _viewController.id;
+    // Platform views should allow pointer events to pass through to the
+    // underlying platform view content.
+    config.hitTestBehavior = ui.SemanticsHitTestBehavior.transparent;
   }
 
   @override
@@ -737,6 +745,9 @@ class PlatformViewRenderBox extends RenderBox with _PlatformViewGestureMixin {
     super.describeSemanticsConfiguration(config);
     config.isSemanticBoundary = true;
     config.platformViewId = _controller.viewId;
+    // Platform views should allow pointer events to pass through to the
+    // underlying platform view content.
+    config.hitTestBehavior = ui.SemanticsHitTestBehavior.transparent;
   }
 }
 
diff --git a/packages/flutter/lib/src/rendering/sliver_group.dart b/packages/flutter/lib/src/rendering/sliver_group.dart
index 4e99b0e75ea65..feedabb357628 100644
--- a/packages/flutter/lib/src/rendering/sliver_group.dart
+++ b/packages/flutter/lib/src/rendering/sliver_group.dart
@@ -374,16 +374,22 @@ class RenderSliverMainAxisGroup extends RenderSliver
     // If the children's paint extent exceeds the remaining scroll extent of the `RenderSliverMainAxisGroup`,
     // they need to be corrected.
     if (paintOffset > remainingExtent) {
+      // Whether the current remaining space can accommodate all pinned children.
+      final bool pinnedChildrenOverflow =
+          maxScrollObstructionExtent > remainingExtent - constraints.overlap;
       final double paintCorrection = paintOffset - remainingExtent;
       paintOffset = remainingExtent;
       child = firstChild;
       while (child != null) {
         final SliverGeometry childLayoutGeometry = child.geometry!;
-        final bool childIsTooLarge = childLayoutGeometry.paintExtent > remainingExtent;
-        final bool pinnedHeadersOverflow = maxScrollObstructionExtent > remainingExtent;
-        final bool childIsPinnedHeader = childLayoutGeometry.maxScrollObstructionExtent > 0;
-        if (childIsTooLarge || (pinnedHeadersOverflow && childIsPinnedHeader)) {
-          final childParentData = child.parentData! as SliverPhysicalParentData;
+        final childParentData = child.parentData! as SliverPhysicalParentData;
+        final double childMainAxisPaintOffset = switch (constraints.axis) {
+          Axis.vertical => childParentData.paintOffset.dy,
+          Axis.horizontal => childParentData.paintOffset.dx,
+        };
+        final double childPaintEnd = childMainAxisPaintOffset + childLayoutGeometry.paintExtent;
+        final bool childIsPinned = childLayoutGeometry.maxScrollObstructionExtent > 0;
+        if (childPaintEnd > remainingExtent || (pinnedChildrenOverflow && childIsPinned)) {
           childParentData.paintOffset = switch (constraints.axis) {
             Axis.vertical => Offset(0.0, childParentData.paintOffset.dy - paintCorrection),
             Axis.horizontal => Offset(childParentData.paintOffset.dx - paintCorrection, 0.0),
diff --git a/packages/flutter/lib/src/semantics/semantics.dart b/packages/flutter/lib/src/semantics/semantics.dart
index 8bf5f290c9a4e..86f44a09247eb 100644
--- a/packages/flutter/lib/src/semantics/semantics.dart
+++ b/packages/flutter/lib/src/semantics/semantics.dart
@@ -28,6 +28,7 @@ import 'dart:ui'
         StringAttribute,
         TextDirection,
         Tristate;
+import 'dart:ui' as ui show SemanticsHitTestBehavior;
 
 import 'package:collection/collection.dart';
 import 'package:flutter/foundation.dart';
@@ -1020,6 +1021,7 @@ class SemanticsData with Diagnosticable {
     required this.role,
     required this.controlsNodes,
     required this.validationResult,
+    required this.hitTestBehavior,
     required this.inputType,
     required this.locale,
     this.tags,
@@ -1288,6 +1290,9 @@ class SemanticsData with Diagnosticable {
   /// {@macro flutter.semantics.SemanticsProperties.validationResult}
   final SemanticsValidationResult validationResult;
 
+  /// {@macro flutter.semantics.SemanticsProperties.hitTestBehavior}
+  final ui.SemanticsHitTestBehavior hitTestBehavior;
+
   /// {@macro flutter.semantics.SemanticsNode.inputType}
   final SemanticsInputType inputType;
 
@@ -1415,6 +1420,7 @@ class SemanticsData with Diagnosticable {
         other.role == role &&
         other.validationResult == validationResult &&
         other.inputType == inputType &&
+        other.hitTestBehavior == hitTestBehavior &&
         _sortedListsEqual(other.customSemanticsActionIds, customSemanticsActionIds) &&
         setEquals<String>(controlsNodes, other.controlsNodes);
   }
@@ -1451,8 +1457,7 @@ class SemanticsData with Diagnosticable {
       validationResult,
       controlsNodes == null ? null : Object.hashAll(controlsNodes!),
       inputType,
-      traversalParentIdentifier,
-      traversalChildIdentifier,
+      hitTestBehavior,
     ),
   );
 
@@ -1611,6 +1616,7 @@ class SemanticsProperties extends DiagnosticableTree {
     this.controlsNodes,
     this.inputType,
     this.validationResult = SemanticsValidationResult.none,
+    this.hitTestBehavior,
     this.onTap,
     this.onLongPress,
     this.onScrollLeft,
@@ -2555,6 +2561,13 @@ class SemanticsProperties extends DiagnosticableTree {
   /// {@endtemplate}
   final SemanticsValidationResult validationResult;
 
+  /// {@template flutter.semantics.SemanticsProperties.hitTestBehavior}
+  /// Describes how the semantic node should behave during hit testing.
+  ///
+  /// See [ui.SemanticsHitTestBehavior] for more details.
+  /// {@endtemplate}
+  final ui.SemanticsHitTestBehavior? hitTestBehavior;
+
   /// {@template flutter.semantics.SemanticsProperties.inputType}
   /// The input type for of a editable widget.
   ///
@@ -3235,7 +3248,8 @@ class SemanticsNode with DiagnosticableTreeMixin {
         _headingLevel != config._headingLevel ||
         _linkUrl != config._linkUrl ||
         _role != config.role ||
-        _validationResult != config.validationResult;
+        _validationResult != config.validationResult ||
+        _hitTestBehavior != config.hitTestBehavior;
   }
 
   // TAGS, LABELS, ACTIONS
@@ -3529,6 +3543,10 @@ class SemanticsNode with DiagnosticableTreeMixin {
   SemanticsValidationResult get validationResult => _validationResult;
   SemanticsValidationResult _validationResult = _kEmptyConfig.validationResult;
 
+  /// {@macro flutter.semantics.SemanticsProperties.hitTestBehavior}
+  ui.SemanticsHitTestBehavior get hitTestBehavior => _hitTestBehavior;
+  ui.SemanticsHitTestBehavior _hitTestBehavior = ui.SemanticsHitTestBehavior.defer;
+
   /// {@template flutter.semantics.SemanticsNode.inputType}
   /// The input type for of a editable node.
   ///
@@ -3609,6 +3627,7 @@ class SemanticsNode with DiagnosticableTreeMixin {
     _role = config._role;
     _controlsNodes = config._controlsNodes;
     _validationResult = config._validationResult;
+    _hitTestBehavior = config._hitTestBehavior;
     _inputType = config._inputType;
     _locale = config.locale;
 
@@ -3663,6 +3682,7 @@ class SemanticsNode with DiagnosticableTreeMixin {
     SemanticsRole role = _role;
     Set<String>? controlsNodes = _controlsNodes;
     SemanticsValidationResult validationResult = _validationResult;
+    ui.SemanticsHitTestBehavior hitTestBehavior = _hitTestBehavior;
     SemanticsInputType inputType = _inputType;
     final Locale? locale = _locale;
     final customSemanticsActionIds = <int>{};
@@ -3727,6 +3747,9 @@ class SemanticsNode with DiagnosticableTreeMixin {
         if (inputType == SemanticsInputType.none) {
           inputType = node._inputType;
         }
+        if (hitTestBehavior == ui.SemanticsHitTestBehavior.defer) {
+          hitTestBehavior = node._hitTestBehavior;
+        }
         if (tooltip == '') {
           tooltip = node._tooltip;
         }
@@ -3818,6 +3841,7 @@ class SemanticsNode with DiagnosticableTreeMixin {
       role: role,
       controlsNodes: controlsNodes,
       validationResult: validationResult,
+      hitTestBehavior: hitTestBehavior,
       inputType: inputType,
       locale: locale,
     );
@@ -3989,6 +4013,7 @@ class SemanticsNode with DiagnosticableTreeMixin {
       role: data.role,
       controlsNodes: data.controlsNodes?.toList(),
       validationResult: data.validationResult,
+      hitTestBehavior: data.hitTestBehavior,
       inputType: data.inputType,
       locale: data.locale,
     );
@@ -6412,6 +6437,14 @@ class SemanticsConfiguration {
     _hasBeenAnnotated = true;
   }
 
+  /// {@macro flutter.semantics.SemanticsProperties.hitTestBehavior}
+  ui.SemanticsHitTestBehavior get hitTestBehavior => _hitTestBehavior;
+  ui.SemanticsHitTestBehavior _hitTestBehavior = ui.SemanticsHitTestBehavior.defer;
+  set hitTestBehavior(ui.SemanticsHitTestBehavior value) {
+    _hitTestBehavior = value;
+    _hasBeenAnnotated = true;
+  }
+
   /// {@macro flutter.semantics.SemanticsProperties.inputType}
   SemanticsInputType get inputType => _inputType;
   SemanticsInputType _inputType = SemanticsInputType.none;
@@ -6523,6 +6556,10 @@ class SemanticsConfiguration {
     if (_hasExplicitRole && other._hasExplicitRole) {
       return false;
     }
+    if (_hitTestBehavior != ui.SemanticsHitTestBehavior.defer ||
+        other._hitTestBehavior != ui.SemanticsHitTestBehavior.defer) {
+      return false;
+    }
     return true;
   }
 
@@ -6633,6 +6670,11 @@ class SemanticsConfiguration {
       child._accessiblityFocusBlockType,
     );
 
+    if (_hitTestBehavior == ui.SemanticsHitTestBehavior.defer &&
+        child._hitTestBehavior != ui.SemanticsHitTestBehavior.defer) {
+      _hitTestBehavior = child._hitTestBehavior;
+    }
+
     _hasBeenAnnotated = hasBeenAnnotated || child.hasBeenAnnotated;
   }
 
@@ -6678,7 +6720,8 @@ class SemanticsConfiguration {
       .._role = _role
       .._controlsNodes = _controlsNodes
       .._validationResult = _validationResult
-      .._inputType = _inputType;
+      .._inputType = _inputType
+      .._hitTestBehavior = _hitTestBehavior;
   }
 }
 
diff --git a/packages/flutter/lib/src/widgets/basic.dart b/packages/flutter/lib/src/widgets/basic.dart
index 779882d749525..ed1c909646119 100644
--- a/packages/flutter/lib/src/widgets/basic.dart
+++ b/packages/flutter/lib/src/widgets/basic.dart
@@ -9,7 +9,9 @@
 library;
 
 import 'dart:math' as math;
-import 'dart:ui' as ui show Image, ImageFilter, SemanticsInputType, TextHeightBehavior;
+import 'dart:ui'
+    as ui
+    show Image, ImageFilter, SemanticsHitTestBehavior, SemanticsInputType, TextHeightBehavior;
 
 import 'package:flutter/animation.dart';
 import 'package:flutter/foundation.dart';
@@ -4047,6 +4049,7 @@ sealed class _SemanticsBase extends SingleChildRenderObjectWidget {
     required SemanticsRole? role,
     required Set<String>? controlsNodes,
     required SemanticsValidationResult validationResult,
+    required ui.SemanticsHitTestBehavior? hitTestBehavior,
     required ui.SemanticsInputType? inputType,
     required Locale? localeForSubtree,
   }) : this.fromProperties(
@@ -4132,6 +4135,7 @@ sealed class _SemanticsBase extends SingleChildRenderObjectWidget {
            role: role,
            controlsNodes: controlsNodes,
            validationResult: validationResult,
+           hitTestBehavior: hitTestBehavior,
            inputType: inputType,
          ),
        );
@@ -4377,6 +4381,7 @@ class SliverSemantics extends _SemanticsBase {
     super.role,
     super.controlsNodes,
     super.validationResult = SemanticsValidationResult.none,
+    super.hitTestBehavior,
     super.inputType,
     super.localeForSubtree,
   }) : super(child: sliver);
@@ -7959,6 +7964,7 @@ class Semantics extends _SemanticsBase {
     super.role,
     super.controlsNodes,
     super.validationResult = SemanticsValidationResult.none,
+    super.hitTestBehavior,
     super.inputType,
     super.localeForSubtree,
   });
diff --git a/packages/flutter/lib/src/widgets/form.dart b/packages/flutter/lib/src/widgets/form.dart
index e04735b3dc850..7015aededc6e3 100644
--- a/packages/flutter/lib/src/widgets/form.dart
+++ b/packages/flutter/lib/src/widgets/form.dart
@@ -251,6 +251,7 @@ class FormState extends State<Form> {
     _hasInteractedByUser = _fields.any(
       (FormFieldState<dynamic> field) => field._hasInteractedByUser.value,
     );
+
     _forceRebuild();
   }
 
@@ -271,6 +272,8 @@ class FormState extends State<Form> {
   @protected
   @override
   Widget build(BuildContext context) {
+    final bool hasError = _fields.any((FormFieldState<dynamic> field) => field.hasError);
+
     switch (widget.autovalidateMode) {
       case AutovalidateMode.always:
         _validate(View.of(context));
@@ -278,6 +281,10 @@ class FormState extends State<Form> {
         if (_hasInteractedByUser) {
           _validate(View.of(context));
         }
+      case AutovalidateMode.onUserInteractionIfError:
+        if (_hasInteractedByUser && hasError) {
+          _validate(View.of(context));
+        }
       case AutovalidateMode.onUnfocus:
       case AutovalidateMode.disabled:
         break;
@@ -751,6 +758,7 @@ class FormFieldState<T> extends State<FormField<T>> with RestorationMixin {
         });
       case AutovalidateMode.onUnfocus:
       case AutovalidateMode.onUserInteraction:
+      case AutovalidateMode.onUserInteractionIfError:
       case AutovalidateMode.disabled:
       case null:
         break;
@@ -776,6 +784,10 @@ class FormFieldState<T> extends State<FormField<T>> with RestorationMixin {
           if (_hasInteractedByUser.value) {
             _validate();
           }
+        case AutovalidateMode.onUserInteractionIfError:
+          if (_hasInteractedByUser.value && hasError) {
+            _validate();
+          }
         case AutovalidateMode.onUnfocus:
         case AutovalidateMode.disabled:
           break;
@@ -831,4 +843,11 @@ enum AutovalidateMode {
   /// In order to validate all fields of a [Form] after the first time the user interacts
   /// with one, use [always] instead.
   onUnfocus,
+
+  /// Used to auto-validate [Form] and [FormField] after each user
+  /// interaction, only if the the field already has an error.
+  ///
+  /// This is useful for reducing unnecessary validation calls while
+  /// still ensuring errors are re-checked when the user attempts to fix them.
+  onUserInteractionIfError,
 }
diff --git a/packages/flutter/test/material/bottom_sheet_test.dart b/packages/flutter/test/material/bottom_sheet_test.dart
index 9753cca8b98e5..6c2281dc29a9a 100644
--- a/packages/flutter/test/material/bottom_sheet_test.dart
+++ b/packages/flutter/test/material/bottom_sheet_test.dart
@@ -893,11 +893,18 @@ void main() {
                 TestSemantics(
                   children: <TestSemantics>[
                     TestSemantics(
-                      label: 'Dialog',
-                      textDirection: TextDirection.ltr,
-                      flags: <SemanticsFlag>[SemanticsFlag.scopesRoute, SemanticsFlag.namesRoute],
                       children: <TestSemantics>[
-                        TestSemantics(label: 'BottomSheet', textDirection: TextDirection.ltr),
+                        TestSemantics(
+                          label: 'Dialog',
+                          textDirection: TextDirection.ltr,
+                          flags: <SemanticsFlag>[
+                            SemanticsFlag.scopesRoute,
+                            SemanticsFlag.namesRoute,
+                          ],
+                          children: <TestSemantics>[
+                            TestSemantics(label: 'BottomSheet', textDirection: TextDirection.ltr),
+                          ],
+                        ),
                       ],
                     ),
                   ],
@@ -1069,14 +1076,24 @@ void main() {
                 TestSemantics(
                   children: <TestSemantics>[
                     TestSemantics(
-                      label: 'Dialog',
-                      textDirection: TextDirection.ltr,
-                      flags: <SemanticsFlag>[SemanticsFlag.scopesRoute, SemanticsFlag.namesRoute],
                       children: <TestSemantics>[
                         TestSemantics(
-                          flags: <SemanticsFlag>[SemanticsFlag.hasImplicitScrolling],
+                          label: 'Dialog',
+                          textDirection: TextDirection.ltr,
+                          flags: <SemanticsFlag>[
+                            SemanticsFlag.scopesRoute,
+                            SemanticsFlag.namesRoute,
+                          ],
                           children: <TestSemantics>[
-                            TestSemantics(label: 'BottomSheet', textDirection: TextDirection.ltr),
+                            TestSemantics(
+                              flags: <SemanticsFlag>[SemanticsFlag.hasImplicitScrolling],
+                              children: <TestSemantics>[
+                                TestSemantics(
+                                  label: 'BottomSheet',
+                                  textDirection: TextDirection.ltr,
+                                ),
+                              ],
+                            ),
                           ],
                         ),
                       ],
@@ -1145,14 +1162,24 @@ void main() {
                 TestSemantics(
                   children: <TestSemantics>[
                     TestSemantics(
-                      label: 'Dialog',
-                      textDirection: TextDirection.ltr,
-                      flags: <SemanticsFlag>[SemanticsFlag.scopesRoute, SemanticsFlag.namesRoute],
                       children: <TestSemantics>[
                         TestSemantics(
-                          flags: <SemanticsFlag>[SemanticsFlag.hasImplicitScrolling],
+                          label: 'Dialog',
+                          textDirection: TextDirection.ltr,
+                          flags: <SemanticsFlag>[
+                            SemanticsFlag.scopesRoute,
+                            SemanticsFlag.namesRoute,
+                          ],
                           children: <TestSemantics>[
-                            TestSemantics(label: 'BottomSheet', textDirection: TextDirection.ltr),
+                            TestSemantics(
+                              flags: <SemanticsFlag>[SemanticsFlag.hasImplicitScrolling],
+                              children: <TestSemantics>[
+                                TestSemantics(
+                                  label: 'BottomSheet',
+                                  textDirection: TextDirection.ltr,
+                                ),
+                              ],
+                            ),
                           ],
                         ),
                       ],
@@ -1217,17 +1244,24 @@ void main() {
                 TestSemantics(
                   children: <TestSemantics>[
                     TestSemantics(
-                      label: 'Dialog',
-                      textDirection: TextDirection.ltr,
-                      flags: <SemanticsFlag>[SemanticsFlag.scopesRoute, SemanticsFlag.namesRoute],
                       children: <TestSemantics>[
                         TestSemantics(
-                          flags: <SemanticsFlag>[SemanticsFlag.isButton],
-                          actions: <SemanticsAction>[SemanticsAction.tap],
-                          label: 'Dismiss',
+                          label: 'Dialog',
                           textDirection: TextDirection.ltr,
+                          flags: <SemanticsFlag>[
+                            SemanticsFlag.scopesRoute,
+                            SemanticsFlag.namesRoute,
+                          ],
+                          children: <TestSemantics>[
+                            TestSemantics(
+                              flags: <SemanticsFlag>[SemanticsFlag.isButton],
+                              actions: <SemanticsAction>[SemanticsAction.tap],
+                              label: 'Dismiss',
+                              textDirection: TextDirection.ltr,
+                            ),
+                            TestSemantics(label: 'BottomSheet', textDirection: TextDirection.ltr),
+                          ],
                         ),
-                        TestSemantics(label: 'BottomSheet', textDirection: TextDirection.ltr),
                       ],
                     ),
                   ],
@@ -2958,6 +2992,61 @@ void main() {
     // Test with theme.platform = iOS on different real platforms.
     await pumpModalBottomSheetWithTheme(TargetPlatform.iOS);
   }, variant: TargetPlatformVariant.all());
+
+  testWidgets('Modal bottom sheet has hitTestBehavior.opaque to prevent dismissal on empty areas', (
+    WidgetTester tester,
+  ) async {
+    final semantics = SemanticsTester(tester);
+    late BuildContext savedContext;
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Builder(
+          builder: (BuildContext context) {
+            savedContext = context;
+            return Container();
+          },
+        ),
+      ),
+    );
+
+    await tester.pump();
+
+    showModalBottomSheet<void>(
+      context: savedContext,
+      builder: (BuildContext context) => Container(
+        height: 200,
+        color: Colors.blue,
+        child: const Center(child: Text('Modal Bottom Sheet')),
+      ),
+    );
+
+    await tester.pumpAndSettle();
+
+    expect(find.text('Modal Bottom Sheet'), findsOneWidget);
+
+    // Verify the route-level Semantics has opaque hitTestBehavior
+    // This prevents clicks inside the bottom sheet from passing through to the barrier
+    final List<Semantics> allSemantics = tester
+        .widgetList<Semantics>(
+          find.ancestor(of: find.text('Modal Bottom Sheet'), matching: find.byType(Semantics)),
+        )
+        .toList();
+
+    final Semantics routeSemantics = allSemantics.firstWhere(
+      (Semantics s) => s.properties.hitTestBehavior == SemanticsHitTestBehavior.opaque,
+    );
+
+    expect(routeSemantics.properties.hitTestBehavior, SemanticsHitTestBehavior.opaque);
+
+    final Semantics widgetSemantics = allSemantics.firstWhere(
+      (Semantics s) => s.properties.scopesRoute ?? false,
+    );
+
+    expect(widgetSemantics.properties.scopesRoute, true);
+
+    semantics.dispose();
+  });
 }
 
 class _TestPage extends StatelessWidget {
diff --git a/packages/flutter/test/material/carousel_test.dart b/packages/flutter/test/material/carousel_test.dart
index 2e9fb5199087e..5bdc3dc4c4307 100644
--- a/packages/flutter/test/material/carousel_test.dart
+++ b/packages/flutter/test/material/carousel_test.dart
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:math' as math;
 import 'dart:ui';
 
 import 'package:flutter/material.dart';
@@ -1990,7 +1989,6 @@ void main() {
             body: CarouselView(
               itemExtent: 300,
               controller: controller,
-              itemSnapping: true,
               onIndexChanged: (int index) {
                 leadingIndex = index;
               },
@@ -2022,121 +2020,74 @@ void main() {
       expect(leadingIndex, equals(1));
     });
 
-    testWidgets('CarouselView shows correct item after animation with symmetric flexWeights', (
-      WidgetTester tester,
-    ) async {
-      final controller = CarouselController();
-      addTearDown(controller.dispose);
-      var leadingIndex = 0;
+    testWidgets(
+      'CarouselView.weighted shows correct item after animation with symmetric flexWeights',
+      (WidgetTester tester) async {
+        final controller = CarouselController();
+        addTearDown(controller.dispose);
+        var leadingIndex = 0;
 
-      await tester.pumpWidget(
-        MaterialApp(
-          home: Scaffold(
-            body: CarouselView.weighted(
-              flexWeights: const <int>[2, 5, 2],
-              controller: controller,
-              itemSnapping: true,
-              onIndexChanged: (int index) {
-                leadingIndex = index;
-              },
-              children: List<Widget>.generate(6, (int i) => Text('Item $i')),
+        await tester.pumpWidget(
+          MaterialApp(
+            home: Scaffold(
+              body: CarouselView.weighted(
+                flexWeights: const [2, 5, 2],
+                controller: controller,
+                onIndexChanged: (int index) => leadingIndex = index,
+                children: List.generate(6, (i) => Text('Item $i')),
+              ),
             ),
           ),
-        ),
-      );
-      await tester.pumpAndSettle();
-
-      controller.animateToItem(
-        4,
-        duration: const Duration(milliseconds: 200),
-        curve: Curves.linear,
-      );
-      await tester.pumpAndSettle();
-
-      expect(controller.leadingItem, equals(4));
-      expect(leadingIndex, equals(4));
-
-      final double visible4 = visiblePortionOf(tester, 'Item 4');
-      final double visible3 = visiblePortionOf(tester, 'Item 3');
-      final double visible5 = visiblePortionOf(tester, 'Item 5');
-      expect(visible4, greaterThan(visible3));
-      expect(visible4, greaterThan(visible5));
-
-      controller.animateToItem(
-        2,
-        duration: const Duration(milliseconds: 200),
-        curve: Curves.linear,
-      );
-      await tester.pumpAndSettle();
+        );
+        await tester.pumpAndSettle();
 
-      expect(controller.leadingItem, equals(2));
-      expect(leadingIndex, equals(2));
+        // Animate the carousel so item 4 is placed in the first position with max weight (5)
+        // in `flexWeights`, resulting in item 3 as the leading item.
+        controller.animateToItem(
+          4,
+          duration: const Duration(milliseconds: 200),
+          curve: Curves.linear,
+        );
+        await tester.pumpAndSettle();
 
-      final double visible2 = visiblePortionOf(tester, 'Item 2');
-      final double visible1 = visiblePortionOf(tester, 'Item 1');
-      final double visible3After = visiblePortionOf(tester, 'Item 3');
-      expect(visible2, greaterThan(visible1));
-      expect(visible2, greaterThan(visible3After));
-    });
+        expect(controller.leadingItem, equals(3));
+        expect(leadingIndex, equals(3));
+        expect(find.text('Item 3'), findsOneWidget);
+      },
+    );
 
-    testWidgets('CarouselView shows correct item after animation with asymmetric flexWeights', (
-      WidgetTester tester,
-    ) async {
-      final controller = CarouselController();
-      addTearDown(controller.dispose);
-      var leadingIndex = 0;
+    testWidgets(
+      'CarouselView.weighted shows correct item after animation with asymmetric flexWeights',
+      (WidgetTester tester) async {
+        final controller = CarouselController();
+        addTearDown(controller.dispose);
+        var leadingIndex = 0;
 
-      await tester.pumpWidget(
-        MaterialApp(
-          home: Scaffold(
-            body: CarouselView.weighted(
-              flexWeights: const <int>[1, 2, 3, 4],
-              controller: controller,
-              itemSnapping: true,
-              onIndexChanged: (int index) {
-                leadingIndex = index;
-              },
-              children: List<Widget>.generate(6, (int i) => Text('Item $i')),
+        await tester.pumpWidget(
+          MaterialApp(
+            home: Scaffold(
+              body: CarouselView.weighted(
+                flexWeights: const [1, 2, 3, 4],
+                controller: controller,
+                onIndexChanged: (int index) => leadingIndex = index,
+                children: List.generate(6, (i) => Text('Item $i')),
+              ),
             ),
           ),
-        ),
-      );
-      await tester.pumpAndSettle();
-
-      controller.animateToItem(
-        4,
-        duration: const Duration(milliseconds: 200),
-        curve: Curves.linear,
-      );
-      await tester.pumpAndSettle();
-
-      expect(controller.leadingItem, equals(4));
-      expect(leadingIndex, equals(4));
-      expect(find.text('Item 4'), findsOneWidget);
-
-      final double visible4 = visiblePortionOf(tester, 'Item 4');
-      final double visible3 = visiblePortionOf(tester, 'Item 3');
-      final double visible5 = visiblePortionOf(tester, 'Item 5');
-      expect(visible4, greaterThan(visible3));
-      expect(visible4, greaterThan(visible5));
-
-      controller.animateToItem(
-        2,
-        duration: const Duration(milliseconds: 200),
-        curve: Curves.linear,
-      );
-      await tester.pumpAndSettle();
+        );
+        await tester.pumpAndSettle();
 
-      expect(controller.leadingItem, equals(2));
-      expect(leadingIndex, equals(2));
-      expect(find.text('Item 2'), findsOneWidget);
+        controller.animateToItem(
+          2,
+          duration: const Duration(milliseconds: 200),
+          curve: Curves.linear,
+        );
+        await tester.pumpAndSettle();
 
-      final double visible2 = visiblePortionOf(tester, 'Item 2');
-      final double visible1 = visiblePortionOf(tester, 'Item 1');
-      final double visible3After = visiblePortionOf(tester, 'Item 3');
-      expect(visible2, greaterThan(visible1));
-      expect(visible2, greaterThan(visible3After));
-    });
+        expect(controller.leadingItem, equals(0));
+        expect(leadingIndex, equals(0));
+      },
+    );
 
     testWidgets('CarouselView shows the correct item after dragging', (WidgetTester tester) async {
       final controller = CarouselController();
@@ -2160,41 +2111,11 @@ void main() {
       );
       await tester.pumpAndSettle();
 
-      // Drag to the left to move to the next item.
       await tester.drag(find.byType(CarouselView), const Offset(-300, 0));
       await tester.pumpAndSettle();
 
-      // Verify the new index based on controller and callback.
-      expect(controller.leadingItem, equals(2));
-      expect(leadingIndex, equals(2));
-
-      // Validate that the dragged item is now the most visible in the viewport.
-      final visibleAreasAfterLeftDrag = List<double>.generate(
-        5,
-        (int i) => visiblePortionOf(tester, 'Item $i'),
-      );
-      final int mostVisibleIndexAfterLeftDrag = visibleAreasAfterLeftDrag.indexWhere(
-        (double area) => area == visibleAreasAfterLeftDrag.reduce(math.max),
-      );
-      expect(mostVisibleIndexAfterLeftDrag, equals(controller.leadingItem));
-
-      // Drag to the right to return to the previous item.
-      await tester.drag(find.byType(CarouselView), const Offset(150, 0));
-      await tester.pumpAndSettle();
-
-      // Verify the updated index.
       expect(controller.leadingItem, equals(1));
       expect(leadingIndex, equals(1));
-
-      // Validate again which item is most visible after dragging back.
-      final visibleAreasAfterRightDrag = List<double>.generate(
-        5,
-        (int i) => visiblePortionOf(tester, 'Item $i'),
-      );
-      final int mostVisibleIndexAfterRightDrag = visibleAreasAfterRightDrag.indexWhere(
-        (double area) => area == visibleAreasAfterRightDrag.reduce(math.max),
-      );
-      expect(mostVisibleIndexAfterRightDrag, equals(controller.leadingItem));
     });
 
     testWidgets(
@@ -2208,28 +2129,23 @@ void main() {
           MaterialApp(
             home: Scaffold(
               body: CarouselView.weighted(
-                flexWeights: const <int>[5, 5, 2, 3],
+                flexWeights: const [5, 5, 2, 3],
                 controller: controller,
                 itemSnapping: true,
-                onIndexChanged: (int index) {
-                  leadingIndex = index;
-                },
-                children: List<Widget>.generate(4, (int i) => Text('Item $i')),
+                onIndexChanged: (int index) => leadingIndex = index,
+                children: List.generate(4, (i) => Text('Item $i')),
               ),
             ),
           ),
         );
         await tester.pumpAndSettle();
 
-        // Initially, the first item with max weight should be leading (index 0).
+        // First max-weight item wins initially
         expect(controller.leadingItem, equals(0));
         expect(leadingIndex, equals(0));
+        expect(find.text('Item 0'), findsOneWidget);
 
-        final double visible0 = visiblePortionOf(tester, 'Item 0');
-        final double visible1 = visiblePortionOf(tester, 'Item 1');
-        expect(visible0, greaterThanOrEqualTo(visible1));
-
-        // Scroll forward so the second max weight item is more visible.
+        // Move to the next max-weight item
         controller.animateToItem(
           1,
           duration: const Duration(milliseconds: 200),
@@ -2237,13 +2153,15 @@ void main() {
         );
         await tester.pumpAndSettle();
 
-        // Leading should now be the second item with max weight (index 1).
         expect(controller.leadingItem, equals(1));
         expect(leadingIndex, equals(1));
+        expect(find.text('Item 1'), findsOneWidget);
       },
     );
 
-    testWidgets('CarouselView starts with the correct initial item', (WidgetTester tester) async {
+    testWidgets('CarouselView.weighted starts with the correct initial item', (
+      WidgetTester tester,
+    ) async {
       final controller = CarouselController(initialItem: 2);
       addTearDown(controller.dispose);
 
@@ -2259,15 +2177,11 @@ void main() {
           ),
         ),
       );
-      await tester.pumpAndSettle();
 
-      expect(controller.leadingItem, equals(2));
-      expect(find.text('Item 2'), findsOneWidget);
+      await tester.pumpAndSettle();
 
-      // Verify that the initial item is centered.
-      final Rect itemRect = tester.getRect(find.text('Item 2'));
-      final double centerX = tester.getCenter(find.byType(CarouselView)).dx;
-      expect(itemRect.center.dx, closeTo(centerX, 1.0)); // Allow a small margin of error.
+      expect(controller.leadingItem, equals(1));
+      expect(find.text('Item 1'), findsOneWidget);
     });
   });
 
@@ -2508,29 +2422,3 @@ Future<void> runCarouselTest({
   expect(find.text('Item 0'), findsOneWidget);
   expect(realOffset(), controller.offset);
 }
-
-double visiblePortionOf(WidgetTester tester, String label) {
-  // Locate the CarouselView widget that defines the visible viewport.
-  final Finder carouselFinder = find.byType(CarouselView);
-
-  // If the item with the given label is not currently in the render tree,
-  // return 0.0 because it is outside the visible area.
-  if (find.text(label).evaluate().isEmpty) {
-    return 0.0;
-  }
-
-  // Get the RenderBox of the CarouselView to determine its visible boundaries.
-  final RenderBox carouselBox = tester.renderObject(carouselFinder);
-  final Rect viewportRect = carouselBox.paintBounds;
-
-  // Get the bounding rectangle of the target item.
-  final Rect itemRect = tester.getRect(find.text(label));
-
-  // Calculate the intersection between the item’s rectangle and the viewport.
-  // This represents the visible portion of the item currently on screen.
-  final Rect intersection = itemRect.intersect(viewportRect);
-
-  // Return the visible area (width * height) of the intersected region.
-  // This helps determine which item is most visible in the Carousel.
-  return intersection.width * intersection.height;
-}
diff --git a/packages/flutter/test/material/dialog_test.dart b/packages/flutter/test/material/dialog_test.dart
index 85581c6c99009..76f4a98d1218c 100644
--- a/packages/flutter/test/material/dialog_test.dart
+++ b/packages/flutter/test/material/dialog_test.dart
@@ -3311,6 +3311,95 @@ void main() {
       semantics.dispose();
     }, variant: TargetPlatformVariant.all());
   });
+
+  testWidgets('Dialog has hitTestBehavior.opaque to prevent dismissal on empty areas', (
+    WidgetTester tester,
+  ) async {
+    final semantics = SemanticsTester(tester);
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Builder(
+            builder: (BuildContext context) {
+              return ElevatedButton(
+                onPressed: () {
+                  showDialog<void>(
+                    context: context,
+                    builder: (BuildContext context) =>
+                        const Dialog(child: SizedBox(width: 200, height: 200)),
+                  );
+                },
+                child: const Text('Show Dialog'),
+              );
+            },
+          ),
+        ),
+      ),
+    );
+
+    await tester.tap(find.text('Show Dialog'));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Dialog), findsOneWidget);
+
+    final Semantics routeSemantics = tester.widget<Semantics>(
+      find.ancestor(of: find.byType(Dialog), matching: find.byType(Semantics)).first,
+    );
+
+    expect(routeSemantics.properties.hitTestBehavior, SemanticsHitTestBehavior.opaque);
+
+    semantics.dispose();
+  });
+
+  testWidgets('AlertDialog has hitTestBehavior.opaque via Dialog', (WidgetTester tester) async {
+    final semantics = SemanticsTester(tester);
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Builder(
+            builder: (BuildContext context) {
+              return ElevatedButton(
+                onPressed: () {
+                  showDialog<void>(
+                    context: context,
+                    builder: (BuildContext context) => AlertDialog(
+                      title: const Text('Test Dialog'),
+                      content: const SizedBox(width: 200, height: 100),
+                      actions: <Widget>[
+                        TextButton(
+                          onPressed: () => Navigator.pop(context),
+                          child: const Text('OK'),
+                        ),
+                      ],
+                    ),
+                  );
+                },
+                child: const Text('Show Dialog'),
+              );
+            },
+          ),
+        ),
+      ),
+    );
+
+    await tester.tap(find.text('Show Dialog'));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(AlertDialog), findsOneWidget);
+    expect(find.byType(Dialog), findsOneWidget);
+
+    // Find the route-level Semantics with hitTestBehavior.opaque
+    // (wraps the entire dialog content, above the Dialog widget)
+    final Semantics routeSemantics = tester.widget<Semantics>(
+      find.ancestor(of: find.byType(Dialog), matching: find.byType(Semantics)).first,
+    );
+
+    expect(routeSemantics.properties.hitTestBehavior, SemanticsHitTestBehavior.opaque);
+
+    semantics.dispose();
+  });
 }
 
 @pragma('vm:entry-point')
diff --git a/packages/flutter/test/material/dropdown_test.dart b/packages/flutter/test/material/dropdown_test.dart
index 4b884d503b833..b0917cdb62ca1 100644
--- a/packages/flutter/test/material/dropdown_test.dart
+++ b/packages/flutter/test/material/dropdown_test.dart
@@ -1460,6 +1460,7 @@ void main() {
                       role: SemanticsRole.menu,
                       flags: <SemanticsFlag>[SemanticsFlag.scopesRoute, SemanticsFlag.namesRoute],
                       label: 'Popup menu',
+                      textDirection: TextDirection.ltr,
                       children: <TestSemantics>[
                         TestSemantics(
                           children: <TestSemantics>[
diff --git a/packages/flutter/test/rendering/platform_view_test.dart b/packages/flutter/test/rendering/platform_view_test.dart
index 35780bfabb867..ab28d30b838c7 100644
--- a/packages/flutter/test/rendering/platform_view_test.dart
+++ b/packages/flutter/test/rendering/platform_view_test.dart
@@ -557,6 +557,22 @@ void main() {
       });
     });
   });
+
+  test('PlatformViewRenderBox has transparent hitTestBehavior in semantics', () {
+    final controller = FakePlatformViewController(0);
+    final renderBox = PlatformViewRenderBox(
+      controller: controller,
+      hitTestBehavior: PlatformViewHitTestBehavior.opaque,
+      gestureRecognizers: <Factory<OneSequenceGestureRecognizer>>{},
+    );
+
+    final config = SemanticsConfiguration();
+    renderBox.describeSemanticsConfiguration(config);
+
+    expect(config.hitTestBehavior, ui.SemanticsHitTestBehavior.transparent);
+    expect(config.isSemanticBoundary, true);
+    expect(config.platformViewId, 0);
+  });
 }
 
 ui.PointerData _pointerData(
diff --git a/packages/flutter/test/semantics/semantics_test.dart b/packages/flutter/test/semantics/semantics_test.dart
index 9523b53cced89..b34f74baf94c8 100644
--- a/packages/flutter/test/semantics/semantics_test.dart
+++ b/packages/flutter/test/semantics/semantics_test.dart
@@ -1035,6 +1035,34 @@ void main() {
     expect(config.customSemanticsActions[customAction], same(onCustomAction));
   });
 
+  test('SemanticsConfiguration.copy() preserves hitTestBehavior', () {
+    final config = SemanticsConfiguration()
+      ..isSemanticBoundary = true
+      ..label = 'test'
+      ..hitTestBehavior = SemanticsHitTestBehavior.opaque;
+
+    expect(config.hitTestBehavior, SemanticsHitTestBehavior.opaque);
+
+    final SemanticsConfiguration copy = config.copy();
+
+    expect(copy.hitTestBehavior, SemanticsHitTestBehavior.opaque);
+    expect(copy.isSemanticBoundary, isTrue);
+    expect(copy.label, 'test');
+  });
+
+  test('SemanticsConfiguration.copy() preserves all hitTestBehavior values', () {
+    final deferConfig = SemanticsConfiguration();
+    expect(deferConfig.copy().hitTestBehavior, SemanticsHitTestBehavior.defer);
+
+    final opaqueConfig = SemanticsConfiguration()
+      ..hitTestBehavior = SemanticsHitTestBehavior.opaque;
+    expect(opaqueConfig.copy().hitTestBehavior, SemanticsHitTestBehavior.opaque);
+
+    final transparentConfig = SemanticsConfiguration()
+      ..hitTestBehavior = SemanticsHitTestBehavior.transparent;
+    expect(transparentConfig.copy().hitTestBehavior, SemanticsHitTestBehavior.transparent);
+  });
+
   test('SemanticsOwner dispatches memory events', () async {
     await expectLater(
       await memoryEvents(
diff --git a/packages/flutter/test/widgets/form_test.dart b/packages/flutter/test/widgets/form_test.dart
index 1aea5d31dcd50..a3f97eb406584 100644
--- a/packages/flutter/test/widgets/form_test.dart
+++ b/packages/flutter/test/widgets/form_test.dart
@@ -840,6 +840,99 @@ void main() {
     },
   );
 
+  testWidgets(
+    'Does not auto-validate before value changes when autovalidateMode is set to onUserInteractionIfError',
+    (WidgetTester tester) async {
+      late FormFieldState<String> formFieldState;
+
+      String? errorText(String? value) => (value == null || value.isEmpty) ? 'Required' : null;
+
+      Widget builder() {
+        return MaterialApp(
+          home: MediaQuery(
+            data: const MediaQueryData(),
+            child: Directionality(
+              textDirection: TextDirection.ltr,
+              child: Center(
+                child: Material(
+                  child: FormField<String>(
+                    initialValue: 'foo',
+                    autovalidateMode: AutovalidateMode.onUserInteractionIfError,
+                    builder: (FormFieldState<String> state) {
+                      formFieldState = state;
+                      return Container();
+                    },
+                    validator: errorText,
+                  ),
+                ),
+              ),
+            ),
+          ),
+        );
+      }
+
+      await tester.pumpWidget(builder());
+
+      // The form field has no error.
+      expect(formFieldState.hasError, isFalse);
+      // No "Required" error is visible.
+      expect(find.text('Required'), findsNothing);
+    },
+  );
+
+  testWidgets(
+    'Does not auto-validate before value changes even when initialValue is empty and autovalidateMode is set to onUserInteractionIfError',
+    (WidgetTester tester) async {
+      late FormFieldState<String> formFieldState;
+
+      String? errorText(String? value) => (value == null || value.isEmpty) ? 'Required' : null;
+
+      Widget builder() {
+        return MaterialApp(
+          home: MediaQuery(
+            data: const MediaQueryData(),
+            child: Directionality(
+              textDirection: TextDirection.ltr,
+              child: Center(
+                child: Material(
+                  child: FormField<String>(
+                    autovalidateMode: AutovalidateMode.onUserInteractionIfError,
+                    builder: (FormFieldState<String> state) {
+                      formFieldState = state;
+                      return Column(
+                        mainAxisSize: MainAxisSize.min,
+                        children: <Widget>[
+                          Container(),
+                          if (state.errorText != null) Text(state.errorText!),
+                        ],
+                      );
+                    },
+                    validator: errorText,
+                  ),
+                ),
+              ),
+            ),
+          ),
+        );
+      }
+
+      await tester.pumpWidget(builder());
+
+      expect(formFieldState.hasError, isFalse);
+
+      expect(find.text('Required'), findsNothing);
+
+      expect(formFieldState.errorText, isNull);
+
+      formFieldState.validate();
+      await tester.pump();
+
+      expect(formFieldState.hasError, isTrue);
+
+      expect(find.text('Required'), findsOneWidget);
+    },
+  );
+
   testWidgets('auto-validate before value changes if autovalidateMode was set to always', (
     WidgetTester tester,
   ) async {
@@ -998,6 +1091,74 @@ void main() {
     },
   );
 
+  testWidgets(
+    'Form with AutovalidateMode.onUserInteractionIfError only revalidates when user interacts after an error exists',
+    (WidgetTester tester) async {
+      final formState = GlobalKey<FormState>();
+      String? errorText(String? value) => (value == null || value.isEmpty) ? 'Required' : null;
+
+      Widget builder() {
+        return MaterialApp(
+          theme: ThemeData(),
+          home: MediaQuery(
+            data: const MediaQueryData(),
+            child: Directionality(
+              textDirection: TextDirection.ltr,
+              child: Center(
+                child: Form(
+                  key: formState,
+                  autovalidateMode: AutovalidateMode.onUserInteractionIfError,
+                  child: Material(
+                    child: TextFormField(initialValue: 'foo', validator: errorText),
+                  ),
+                ),
+              ),
+            ),
+          ),
+        );
+      }
+
+      await tester.pumpWidget(builder());
+
+      // No error text is visible yet. (Initial valid state).
+      expect(find.text('Required'), findsNothing);
+
+      // User types valid input 'bar' → autovalidate is disabled → still no error.
+      await tester.enterText(find.byType(TextFormField), 'bar');
+      await tester.pump();
+      expect(find.text('Required'), findsNothing);
+
+      // Clear the input (invalid).
+      await tester.enterText(find.byType(TextFormField), '');
+      await tester.pump();
+
+      // Manually submit form to show the initial error (AutovalidateMode is now active).
+      formState.currentState!.validate();
+      expect(find.text('Required'), findsNothing);
+      await tester.pump();
+
+      // Verify error is shown.
+      expect(find.text('Required'), findsOneWidget);
+
+      // Now user interacts again with valid text ('baz') → validation auto-runs and clears the error.
+      await tester.enterText(find.byType(TextFormField), 'baz');
+      await tester.pump();
+      expect(find.text('Required'), findsNothing);
+
+      // Check the behavior of a manual validate when the text is already valid.
+      // This should *confirm* the error is cleared, not re-introduce it.
+      formState.currentState!.validate();
+      await tester.pump();
+      expect(find.text('Required'), findsNothing);
+
+      // Resetting should clear form (already cleared, but a safety check).
+      await tester.enterText(find.byType(TextFormField), '');
+      formState.currentState!.reset();
+      await tester.pump();
+      expect(find.text('Required'), findsNothing);
+    },
+  );
+
   // Regression test for https://github.com/flutter/flutter/issues/63753.
   testWidgets('Validate form should return correct validation if the value is composing', (
     WidgetTester tester,
diff --git a/packages/flutter/test/widgets/sliver_main_axis_group_test.dart b/packages/flutter/test/widgets/sliver_main_axis_group_test.dart
index 463050b760dd2..ecdb21ffff049 100644
--- a/packages/flutter/test/widgets/sliver_main_axis_group_test.dart
+++ b/packages/flutter/test/widgets/sliver_main_axis_group_test.dart
@@ -1518,6 +1518,69 @@ void main() {
     expect(semantics.nodesWith(label: 'b'), hasLength(1));
     semantics.dispose();
   });
+
+  testWidgets(
+    'nested SliverMainAxisGroup with multiple PinnedHeaderSlivers positions correctly on scroll',
+    (WidgetTester tester) async {
+      final controller = ScrollController();
+      addTearDown(controller.dispose);
+      final List<Key> keys = [GlobalKey(), GlobalKey(), GlobalKey(), GlobalKey()];
+
+      Future<void> pumpWidget({bool reverse = false}) async {
+        return tester.pumpWidget(
+          _buildSliverMainAxisGroup(
+            controller: controller,
+            reverse: reverse,
+            viewportHeight: 300,
+            precedingSlivers: <Widget>[
+              PinnedHeaderSliver(child: SizedBox(height: 30, key: keys[0])),
+            ],
+            otherSlivers: <Widget>[const SliverToBoxAdapter(child: SizedBox(height: 300))],
+            slivers: <Widget>[
+              PinnedHeaderSliver(child: SizedBox(height: 30, key: keys[1])),
+              SliverMainAxisGroup(
+                slivers: [
+                  PinnedHeaderSliver(child: SizedBox(height: 30, key: keys[2])),
+                  const SliverToBoxAdapter(child: SizedBox(height: 30)),
+                  PinnedHeaderSliver(child: SizedBox(height: 30, key: keys[3])),
+                  const SliverToBoxAdapter(child: SizedBox(height: 30)),
+                ],
+              ),
+              const SliverToBoxAdapter(child: SizedBox(height: 30)),
+            ],
+          ),
+        );
+      }
+
+      Future<void> verifyPositions(Map<double, List<double>> offsetToPositions) async {
+        for (final MapEntry<double, List<double>> entry in offsetToPositions.entries) {
+          controller.jumpTo(entry.key);
+          await tester.pumpAndSettle();
+          for (var i = 0; i < keys.length; i++) {
+            expect(tester.getTopLeft(find.byKey(keys[i])).dy, entry.value[i]);
+          }
+        }
+      }
+
+      // Forward direction
+      await pumpWidget();
+      await verifyPositions({
+        10: [0.0, 30.0, 60.0, 110.0],
+        40: [0.0, 30.0, 60.0, 90.0],
+        70: [0.0, 30.0, 50.0, 80.0],
+        100: [0.0, 30.0, 20.0, 50.0],
+      });
+
+      // Reverse direction
+      await pumpWidget(reverse: true);
+      await verifyPositions({
+        10: [270.0, 240.0, 210.0, 160.0],
+        40: [270.0, 240.0, 210.0, 180.0],
+        70: [270.0, 240.0, 220.0, 190.0],
+        100: [270.0, 240.0, 250.0, 220.0],
+      });
+    },
+  );
 }
 
 Widget _buildSliverList({
@@ -1559,6 +1622,7 @@ Widget _buildSliverMainAxisGroup({
   Axis scrollDirection = Axis.vertical,
   bool reverse = false,
   List<Widget> otherSlivers = const <Widget>[],
+  List<Widget> precedingSlivers = const <Widget>[],
 }) {
   return MaterialApp(
     home: Directionality(
@@ -1573,6 +1637,7 @@ Widget _buildSliverMainAxisGroup({
             reverse: reverse,
             controller: controller,
             slivers: <Widget>[
+              ...precedingSlivers,
               SliverMainAxisGroup(slivers: slivers),
               ...otherSlivers,
             ],
diff --git a/packages/flutter_test/test/matchers_test.dart b/packages/flutter_test/test/matchers_test.dart
index bc9f931211fd3..0e6b42b9aa8ee 100644
--- a/packages/flutter_test/test/matchers_test.dart
+++ b/packages/flutter_test/test/matchers_test.dart
@@ -753,6 +753,7 @@ void main() {
         role: ui.SemanticsRole.none,
         controlsNodes: null,
         validationResult: SemanticsValidationResult.none,
+        hitTestBehavior: ui.SemanticsHitTestBehavior.defer,
         inputType: ui.SemanticsInputType.none,
         locale: null,
       );
@@ -1055,6 +1056,7 @@ void main() {
         role: ui.SemanticsRole.none,
         controlsNodes: null,
         validationResult: SemanticsValidationResult.none,
+        hitTestBehavior: ui.SemanticsHitTestBehavior.defer,
         inputType: ui.SemanticsInputType.none,
         locale: null,
       );
@@ -1157,6 +1159,7 @@ void main() {
         role: ui.SemanticsRole.none,
         controlsNodes: null,
         validationResult: SemanticsValidationResult.none,
+        hitTestBehavior: ui.SemanticsHitTestBehavior.defer,
         inputType: ui.SemanticsInputType.none,
         locale: null,
       );
@@ -1264,6 +1267,7 @@ void main() {
         role: ui.SemanticsRole.none,
         controlsNodes: null,
         validationResult: SemanticsValidationResult.none,
+        hitTestBehavior: ui.SemanticsHitTestBehavior.defer,
         inputType: ui.SemanticsInputType.none,
         locale: null,
       );
@@ -1299,6 +1303,7 @@ void main() {
         role: ui.SemanticsRole.none,
         controlsNodes: null,
         validationResult: SemanticsValidationResult.none,
+        hitTestBehavior: ui.SemanticsHitTestBehavior.defer,
         inputType: ui.SemanticsInputType.none,
         locale: null,
       );
@@ -1433,6 +1438,7 @@ void main() {
         role: ui.SemanticsRole.none,
         controlsNodes: null,
         validationResult: SemanticsValidationResult.none,
+        hitTestBehavior: ui.SemanticsHitTestBehavior.defer,
         inputType: ui.SemanticsInputType.none,
         locale: null,
       );