Enable loading snapshots with sound null safety enabled.

common/config.gni

@@ -28,6 +28,7 @@ feature_defines_list = [
   "FLUTTER_RUNTIME_MODE_PROFILE=2",
   "FLUTTER_RUNTIME_MODE_RELEASE=3",
   "FLUTTER_RUNTIME_MODE_JIT_RELEASE=4",
+  "DART_LEGACY_API=[[deprecated]]",
 ]
 
 if (flutter_runtime_mode == "debug") {

common/settings.h

@@ -10,6 +10,7 @@
 #include <chrono>
 #include <cstdint>
 #include <memory>
+#include <optional>
 #include <string>
 #include <vector>
 
@@ -50,12 +51,11 @@ using UnhandledExceptionCallback =
     std::function<bool(const std::string& /* error */,
                        const std::string& /* stack trace */)>;
 
-// TODO(chinmaygarde): Deprecate all the "path" struct members in favor of the
+// TODO(26783): Deprecate all the "path" struct members in favor of the
 // callback that generates the mapping from these paths.
-// https://github.com/flutter/flutter/issues/26783
 using MappingCallback = std::function<std::unique_ptr<fml::Mapping>(void)>;
-using MappingsCallback =
-    std::function<std::vector<std::unique_ptr<const fml::Mapping>>(void)>;
+using Mappings = std::vector<std::unique_ptr<const fml::Mapping>>;
+using MappingsCallback = std::function<Mappings(void)>;
 
 using FrameRasterizedCallback = std::function<void(const FrameTiming&)>;
 

fml/BUILD.gn

@@ -139,7 +139,7 @@ source_set("fml") {
       "platform/darwin/string_range_sanitization.mm",
     ]
 
-    libs += [ "Foundation.framework" ]
+    frameworks = [ "Foundation.framework" ]
   }
 
   if (is_android) {

fml/dart/dart_converter.h

@@ -23,7 +23,11 @@ struct DartConverter<DartConverterMapping> {
       return Dart_Null();
     }
 
-    auto dart_list_handle = Dart_NewListOf(Dart_CoreType_Int, val->GetSize());
+    auto dart_list_handle = Dart_NewListOfTypeFilled(
+        ToDartTypeHandle<size_t>(),                 // type
+        CreateZeroInitializedDartObject<size_t>(),  // sentinel
+        val->GetSize()                              // size
+    );
 
     if (Dart_IsError(dart_list_handle)) {
       FML_LOG(ERROR) << "Error while attempting to allocate a list: "

lib/io/dart_io.cc

@@ -1,6 +1,7 @@
 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+// FLUTTER_NOLINT
 
 #include "flutter/lib/io/dart_io.h"
 
@@ -23,7 +24,7 @@ void DartIO::InitForIsolate(bool may_insecurely_connect_to_all_domains,
   FML_CHECK(!LogIfError(result));
 
   Dart_Handle embedder_config_type =
-      Dart_GetType(io_lib, ToDart("_EmbedderConfig"), 0, nullptr);
+      Dart_GetNonNullableType(io_lib, ToDart("_EmbedderConfig"), 0, nullptr);
   FML_CHECK(!LogIfError(embedder_config_type));
 
   Dart_Handle allow_insecure_connections_result = Dart_SetField(

lib/ui/dart_runtime_hooks.cc

@@ -1,6 +1,7 @@
 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+// FLUTTER_NOLINT
 
 #include "flutter/lib/ui/dart_runtime_hooks.h"
 
@@ -62,17 +63,19 @@ void DartRuntimeHooks::RegisterNatives(tonic::DartLibraryNatives* natives) {
 
 static void PropagateIfError(Dart_Handle result) {
   if (Dart_IsError(result)) {
+    FML_LOG(ERROR) << "Dart Error: " << ::Dart_GetError(result);
     Dart_PropagateError(result);
   }
 }
 
-static Dart_Handle GetFunction(Dart_Handle builtin_library, const char* name) {
+static Dart_Handle InvokeFunction(Dart_Handle builtin_library,
+                                  const char* name) {
   Dart_Handle getter_name = ToDart(name);
   return Dart_Invoke(builtin_library, getter_name, 0, nullptr);
 }
 
 static void InitDartInternal(Dart_Handle builtin_library, bool is_ui_isolate) {
-  Dart_Handle print = GetFunction(builtin_library, "_getPrintClosure");
+  Dart_Handle print = InvokeFunction(builtin_library, "_getPrintClosure");
 
   Dart_Handle internal_library = Dart_LookupLibrary(ToDart("dart:_internal"));
 
@@ -112,7 +115,7 @@ static void InitDartAsync(Dart_Handle builtin_library, bool is_ui_isolate) {
   Dart_Handle schedule_microtask;
   if (is_ui_isolate) {
     schedule_microtask =
-        GetFunction(builtin_library, "_getScheduleMicrotaskClosure");
+        InvokeFunction(builtin_library, "_getScheduleMicrotaskClosure");
   } else {
     Dart_Handle isolate_lib = Dart_LookupLibrary(ToDart("dart:isolate"));
     Dart_Handle method_name =
@@ -130,21 +133,24 @@ static void InitDartIO(Dart_Handle builtin_library,
                        const std::string& script_uri) {
   Dart_Handle io_lib = Dart_LookupLibrary(ToDart("dart:io"));
   Dart_Handle platform_type =
-      Dart_GetType(io_lib, ToDart("_Platform"), 0, nullptr);
+      Dart_GetNonNullableType(io_lib, ToDart("_Platform"), 0, nullptr);
   if (!script_uri.empty()) {
     Dart_Handle result = Dart_SetField(platform_type, ToDart("_nativeScript"),
                                        ToDart(script_uri));
     PropagateIfError(result);
   }
-  Dart_Handle locale_closure =
-      GetFunction(builtin_library, "_getLocaleClosure");
+  // typedef _LocaleClosure = String Function();
+  Dart_Handle /* _LocaleClosure? */ locale_closure =
+      InvokeFunction(builtin_library, "_getLocaleClosure");
+  PropagateIfError(locale_closure);
+  //   static String Function()? _localeClosure;
   Dart_Handle result =
       Dart_SetField(platform_type, ToDart("_localeClosure"), locale_closure);
   PropagateIfError(result);
 
   // Register dart:io service extensions used for network profiling.
   Dart_Handle network_profiling_type =
-      Dart_GetType(io_lib, ToDart("_NetworkProfiling"), 0, nullptr);
+      Dart_GetNonNullableType(io_lib, ToDart("_NetworkProfiling"), 0, nullptr);
   PropagateIfError(network_profiling_type);
   result = Dart_Invoke(network_profiling_type,
                        ToDart("_registerServiceExtension"), 0, nullptr);

lib/ui/hooks.dart

@@ -53,15 +53,15 @@ void _updateWindowMetrics(
   _invoke(window.onMetricsChanged, window._onMetricsChangedZone);
 }
 
-typedef _LocaleClosure = String? Function();
-
-String? _localeClosure() {
+String _localeClosure() {
   if (window.locale == null) {
-    return null;
+    return '';
   }
   return window.locale.toString();
 }
 
+typedef _LocaleClosure = String Function();
+
 @pragma('vm:entry-point')
 // ignore: unused_element
 _LocaleClosure? _getLocaleClosure() => _localeClosure;
@@ -210,9 +210,7 @@ void _drawFrame() {
 }
 
 // ignore: always_declare_return_types, prefer_generic_function_type_aliases
-typedef _UnaryFunction(Null args);
-// ignore: always_declare_return_types, prefer_generic_function_type_aliases
-typedef _BinaryFunction(Null args, Null message);
+typedef _ListStringArgFunction(List<String> args);
 
 @pragma('vm:entry-point')
 // ignore: unused_element
@@ -221,11 +219,7 @@ void _runMainZoned(Function startMainIsolateFunction,
                    List<String> args) {
   startMainIsolateFunction((){
     runZonedGuarded<void>(() {
-      if (userMainFunction is _BinaryFunction) {
-        // This seems to be undocumented but supported by the command line VM.
-        // Let's do the same in case old entry-points are ported to Flutter.
-        (userMainFunction as dynamic)(args, '');
-      } else if (userMainFunction is _UnaryFunction) {
+      if (userMainFunction is _ListStringArgFunction) {
         (userMainFunction as dynamic)(args);
       } else {
         userMainFunction();

lib/ui/text/paragraph.cc

@@ -1,6 +1,7 @@
 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+// FLUTTER_NOLINT
 
 #include "flutter/lib/ui/text/paragraph.h"
 
@@ -132,20 +133,19 @@ tonic::Float32List Paragraph::getRectsForPlaceholders() {
 }
 
 Dart_Handle Paragraph::getPositionForOffset(double dx, double dy) {
-  Dart_Handle result = Dart_NewListOf(Dart_CoreType_Int, 2);
   txt::Paragraph::PositionWithAffinity pos =
       m_paragraph->GetGlyphPositionAtCoordinate(dx, dy);
-  Dart_ListSetAt(result, 0, ToDart(pos.position));
-  Dart_ListSetAt(result, 1, ToDart(static_cast<int>(pos.affinity)));
-  return result;
+  std::vector<size_t> result = {
+      pos.position,                      // size_t already
+      static_cast<size_t>(pos.affinity)  // affinity (enum)
+  };
+  return tonic::DartConverter<decltype(result)>::ToDart(result);
 }
 
 Dart_Handle Paragraph::getWordBoundary(unsigned offset) {
   txt::Paragraph::Range<size_t> point = m_paragraph->GetWordBoundary(offset);
-  Dart_Handle result = Dart_NewListOf(Dart_CoreType_Int, 2);
-  Dart_ListSetAt(result, 0, ToDart(point.start));
-  Dart_ListSetAt(result, 1, ToDart(point.end));
-  return result;
+  std::vector<size_t> result = {point.start, point.end};
+  return tonic::DartConverter<decltype(result)>::ToDart(result);
 }
 
 Dart_Handle Paragraph::getLineBoundary(unsigned offset) {
@@ -159,10 +159,8 @@ Dart_Handle Paragraph::getLineBoundary(unsigned offset) {
       break;
     }
   }
-  Dart_Handle result = Dart_NewListOf(Dart_CoreType_Int, 2);
-  Dart_ListSetAt(result, 0, ToDart(line_start));
-  Dart_ListSetAt(result, 1, ToDart(line_end));
-  return result;
+  std::vector<int> result = {line_start, line_end};
+  return tonic::DartConverter<decltype(result)>::ToDart(result);
 }
 
 tonic::Float64List Paragraph::computeLineMetrics() {

lib/ui/window/platform_configuration.h

@@ -19,20 +19,6 @@
 #include "flutter/lib/ui/window/window.h"
 #include "third_party/tonic/dart_persistent_value.h"
 
-namespace tonic {
-class DartLibraryNatives;
-
-// So tonic::ToDart<std::vector<int64_t>> returns List<int> instead of
-// List<dynamic>.
-template <>
-struct DartListFactory<int64_t> {
-  static Dart_Handle NewList(intptr_t length) {
-    return Dart_NewListOf(Dart_CoreType_Int, length);
-  }
-};
-
-}  // namespace tonic
-
 namespace flutter {
 class FontCollection;
 class PlatformMessage;

runtime/BUILD.gn

@@ -53,6 +53,8 @@ source_set("runtime") {
     "dart_vm_lifecycle.h",
     "embedder_resources.cc",
     "embedder_resources.h",
+    "isolate_configuration.cc",
+    "isolate_configuration.h",
     "platform_data.cc",
     "platform_data.h",
     "ptrace_check.h",
@@ -112,6 +114,7 @@ if (enable_unittests) {
       "dart_lifecycle_unittests.cc",
       "dart_service_isolate_unittests.cc",
       "dart_vm_unittests.cc",
+      "type_conversions_unittests.cc",
     ]
 
     public_configs = [ "//flutter:export_dynamic_symbols" ]