From ffcaa994730dd6aa155a2e6f6a2a327d1158aea8 Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Fri, 2 Jun 2023 13:31:09 -0700
Subject: [PATCH 1/9] improve clarity of existing test title

---
 .../test/general.shard/asset_bundle_variant_test.dart           | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
index 46c7caef6ca87..09f8f5a27a66f 100644
--- a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
@@ -96,7 +96,7 @@ flutter:
       expect(manifest[imageNonVariant], equals(<String>[imageNonVariant]));
     });
 
-    testWithoutContext('Asset directories are recursively searched for assets', () async {
+    testWithoutContext('Asset directories have their subdirectories searched for asset variants', () async {
       const String topLevelImage = 'assets/image.jpg';
       const String secondLevelImage = 'assets/folder/secondLevel.jpg';
       const String secondLevel2xVariant = 'assets/folder/2x/secondLevel.jpg';

From 9c80bf249aaf9879cd5576a0632f21a28a8da25c Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Fri, 2 Jun 2023 18:05:33 -0700
Subject: [PATCH 2/9] stop automatically including main asset when looking for
 candidate variants in image resolution

This _should_ break tests.
---
 packages/flutter/lib/src/services/asset_manifest.dart | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/packages/flutter/lib/src/services/asset_manifest.dart b/packages/flutter/lib/src/services/asset_manifest.dart
index dd62c7d0b8467..c89522919b4a1 100644
--- a/packages/flutter/lib/src/services/asset_manifest.dart
+++ b/packages/flutter/lib/src/services/asset_manifest.dart
@@ -33,8 +33,8 @@ abstract class AssetManifest {
   /// Retrieves metadata about an asset and its variants. Returns null if the
   /// key was not found in the asset manifest.
   ///
-  /// This method considers a main asset to be a variant of itself and
-  /// includes it in the returned list.
+  /// This method considers a main asset to be a variant of itself. The returned
+  /// list will include it if it exists.
   List<AssetMetadata>? getAssetVariants(String key);
 }
 
@@ -83,12 +83,7 @@ class _AssetManifestBin implements AssetManifest {
       _data.remove(key);
     }
 
-    final AssetMetadata mainAsset = AssetMetadata(key: key,
-      targetDevicePixelRatio: null,
-      main: true
-    );
-
-    return <AssetMetadata>[mainAsset, ..._typeCastedData[key]!];
+    return _typeCastedData[key]!;
   }
 
   @override

From a36481e46406b312c6a387ba92f40b7b3ffd4225 Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Sat, 3 Jun 2023 15:09:21 -0700
Subject: [PATCH 3/9] make dpr a non-required field in the underlying asset
 manifest datastructure

---
 .../lib/src/services/asset_manifest.dart      | 12 +++--
 .../test/services/asset_manifest_test.dart    | 11 ++++-
 .../asset_bundle_variant_test.dart            | 48 +++++++++++++++++--
 3 files changed, 60 insertions(+), 11 deletions(-)

diff --git a/packages/flutter/lib/src/services/asset_manifest.dart b/packages/flutter/lib/src/services/asset_manifest.dart
index c89522919b4a1..7451782eaad34 100644
--- a/packages/flutter/lib/src/services/asset_manifest.dart
+++ b/packages/flutter/lib/src/services/asset_manifest.dart
@@ -73,11 +73,15 @@ class _AssetManifestBin implements AssetManifest {
       }
       _typeCastedData[key] = ((_data[key] ?? <Object?>[]) as Iterable<Object?>)
         .cast<Map<Object?, Object?>>()
-        .map((Map<Object?, Object?> data) => AssetMetadata(
+        .map((Map<Object?, Object?> data) {
+          final String asset = data['asset']! as String;
+          final Object? dpr = data['dpr'];
+          return AssetMetadata(
             key: data['asset']! as String,
-            targetDevicePixelRatio: data['dpr']! as double,
-            main: false,
-        ))
+            targetDevicePixelRatio: dpr == null ? null : dpr as double,
+            main: key == asset,
+          );
+        })
         .toList();
 
       _data.remove(key);
diff --git a/packages/flutter/test/services/asset_manifest_test.dart b/packages/flutter/test/services/asset_manifest_test.dart
index e715ba6b352cf..736f62e8d0d1e 100644
--- a/packages/flutter/test/services/asset_manifest_test.dart
+++ b/packages/flutter/test/services/asset_manifest_test.dart
@@ -11,12 +11,19 @@ class TestAssetBundle extends AssetBundle {
     if (key == 'AssetManifest.smcbin') {
       final Map<String, List<Object>> binManifestData = <String, List<Object>>{
         'assets/foo.png': <Object>[
+          <String, Object>{
+            'asset': 'assets/foo.png',
+          },
           <String, Object>{
             'asset': 'assets/2x/foo.png',
             'dpr': 2.0
-          }
+          },
+        ],
+        'assets/bar.png': <Object>[
+          <String, Object>{
+            'asset': 'assets/bar.png',
+          },
         ],
-        'assets/bar.png': <Object>[],
       };
 
       final ByteData data = const StandardMessageCodec().encodeMessage(binManifestData)!;
diff --git a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
index 09f8f5a27a66f..463c60e0e3aff 100644
--- a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
@@ -44,7 +44,11 @@ void main() {
       );
 
       fs.file('.packages').createSync();
+    });
 
+    void createPubspec({
+      required List<String> assets,
+    }) {
       fs.file('pubspec.yaml').writeAsStringSync(
 '''
 name: test
@@ -53,15 +57,14 @@ dependencies:
     sdk: flutter
 flutter:
   assets:
-    - assets/
-    - assets/notAVariant/
-    - assets/folder/
-    - assets/normalFolder/
+${assets.map((String entry) => '    - $entry').join('\n')}
 '''
       );
-    });
+    }
 
     testWithoutContext('Only images in folders named with device pixel ratios (e.g. 2x, 3.0x) should be considered as variants of other images', () async {
+      createPubspec(assets: <String>['assets/', 'assets/notAVariant/']);
+
       const String image = 'assets/image.jpg';
       const String image2xVariant = 'assets/2x/image.jpg';
       const String imageNonVariant = 'assets/notAVariant/image.jpg';
@@ -97,6 +100,8 @@ flutter:
     });
 
     testWithoutContext('Asset directories have their subdirectories searched for asset variants', () async {
+      createPubspec(assets: <String>['assets', 'assets/folder']);
+
       const String topLevelImage = 'assets/image.jpg';
       const String secondLevelImage = 'assets/folder/secondLevel.jpg';
       const String secondLevel2xVariant = 'assets/folder/2x/secondLevel.jpg';
@@ -131,6 +136,8 @@ flutter:
     });
 
     testWithoutContext('Asset paths should never be URI-encoded', () async {
+      createPubspec(assets: <String>['assets/normalFolder']);
+
       const String image = 'assets/normalFolder/i have URI-reserved_characters.jpg';
       const String imageVariant = 'assets/normalFolder/3x/i have URI-reserved_characters.jpg';
 
@@ -160,6 +167,37 @@ flutter:
       expect(manifest, hasLength(1));
       expect(manifest[image], equals(<String>[image, imageVariant]));
     });
+
+    testWithoutContext('Main assets are not included if the file does not exist', () async {
+      createPubspec(assets: <String>['assets/image.png']);
+
+      // We intentionally do not add a 'assets/image.png'.
+      const String imageVariant = 'assets/2x/image.png';
+      final List<String> assets = <String>[
+        imageVariant,
+      ];
+
+      for (final String asset in assets) {
+        final File assetFile = fs.file(asset);
+        assetFile.createSync(recursive: true);
+        assetFile.writeAsStringSync(asset);
+      }
+
+      final ManifestAssetBundle bundle = ManifestAssetBundle(
+        logger: BufferLogger.test(),
+        fileSystem: fs,
+        platform: platform,
+      );
+
+      await bundle.build(
+        packagesPath: '.packages',
+        flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
+      );
+
+      final Map<String, List<String>> manifest = await extractAssetManifestFromBundle(bundle);
+      expect(manifest, hasLength(1));
+      expect(manifest['assets/image.png'], equals(<String>[imageVariant]));
+    });
   });
 
 

From b2dc81cc87bb85d1831a86b95ea827c79f5117f0 Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Sat, 3 Jun 2023 15:12:08 -0700
Subject: [PATCH 4/9] add main asset to variants list, remove default dpr

Let the framework decide what the default DPR is
---
 packages/flutter_tools/lib/src/asset.dart     |  17 +--
 .../asset_bundle_variant_test.dart            | 133 ++++++++++++++++--
 2 files changed, 127 insertions(+), 23 deletions(-)

diff --git a/packages/flutter_tools/lib/src/asset.dart b/packages/flutter_tools/lib/src/asset.dart
index b5a6c8b75dd4d..4eb71f8b8914c 100644
--- a/packages/flutter_tools/lib/src/asset.dart
+++ b/packages/flutter_tools/lib/src/asset.dart
@@ -166,7 +166,6 @@ class ManifestAssetBundle implements AssetBundle {
   DateTime? _lastBuildTimestamp;
 
   // We assume the main asset is designed for a device pixel ratio of 1.0.
-  static const double _defaultResolution = 1.0;
   static const String _kAssetManifestJsonFilename = 'AssetManifest.json';
   static const String _kAssetManifestBinFilename = 'AssetManifest.smcbin';
 
@@ -688,7 +687,7 @@ class ManifestAssetBundle implements AssetBundle {
   DevFSByteContent _createAssetManifestBinary(
     Map<String, List<String>> assetManifest
   ) {
-    double parseScale(String key) {
+    double? parseScale(String key) {
       final Uri assetUri = Uri.parse(key);
       String directoryPath = '';
       if (assetUri.pathSegments.length > 1) {
@@ -699,7 +698,8 @@ class ManifestAssetBundle implements AssetBundle {
       if (match != null && match.groupCount > 0) {
         return double.parse(match.group(1)!);
       }
-      return _defaultResolution;
+
+      return null;
     }
 
     final Map<String, dynamic> result = <String, dynamic>{};
@@ -708,15 +708,12 @@ class ManifestAssetBundle implements AssetBundle {
       final List<dynamic> resultVariants = <dynamic>[];
       final List<String> entries = (manifestEntry.value as List<dynamic>).cast<String>();
       for (final String variant in entries) {
-        if (variant == manifestEntry.key) {
-          // With the newer binary format, don't include the main asset in it's
-          // list of variants. This reduces parsing time at runtime.
-          continue;
-        }
         final Map<String, dynamic> resultVariant = <String, dynamic>{};
-        final double variantDevicePixelRatio = parseScale(variant);
+        final double? variantDevicePixelRatio = parseScale(variant);
         resultVariant['asset'] = variant;
-        resultVariant['dpr'] = variantDevicePixelRatio;
+        if (variantDevicePixelRatio != null) {
+          resultVariant['dpr'] = variantDevicePixelRatio;
+        }
         resultVariants.add(resultVariant);
       }
       result[manifestEntry.key] = resultVariants;
diff --git a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
index 463c60e0e3aff..d09eaf89172ae 100644
--- a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'dart:convert';
+import 'dart:typed_data';
 
 import 'package:file/file.dart';
 import 'package:file/memory.dart';
@@ -15,12 +16,13 @@ import 'package:flutter_tools/src/base/user_messages.dart';
 import 'package:flutter_tools/src/cache.dart';
 
 import 'package:flutter_tools/src/project.dart';
+import 'package:standard_message_codec/standard_message_codec.dart';
 
 import '../src/common.dart';
 
 void main() {
 
-  Future<Map<String, List<String>>> extractAssetManifestFromBundle(ManifestAssetBundle bundle) async {
+  Future<Map<String, List<String>>> extractAssetManifestJsonFromBundle(ManifestAssetBundle bundle) async {
     final String manifestJson = utf8.decode(await bundle.entries['AssetManifest.json']!.contentsAsBytes());
     final Map<String, dynamic> parsedJson = json.decode(manifestJson) as Map<String, dynamic>;
     final Iterable<String> keys = parsedJson.keys;
@@ -30,6 +32,13 @@ void main() {
     return parsedManifest;
   }
 
+  Future<Map<Object?, Object?>> extractAssetManifestSmcBinFromBundle(ManifestAssetBundle bundle) async {
+    final List<int> manifest = await bundle.entries['AssetManifest.smcbin']!.contentsAsBytes();
+    final ByteData asByteData = ByteData.view(Uint8List.fromList(manifest).buffer);
+    final Map<Object?, Object?> decoded = const StandardMessageCodec().decodeMessage(asByteData)! as Map<Object?, Object?>;
+    return decoded;
+  }
+
   group('AssetBundle asset variants (with Unix-style paths)', () {
     late Platform platform;
     late FileSystem fs;
@@ -92,15 +101,37 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestFromBundle(bundle);
-
-      expect(manifest, hasLength(2));
-      expect(manifest[image], equals(<String>[image, image2xVariant]));
-      expect(manifest[imageNonVariant], equals(<String>[imageNonVariant]));
+      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
+
+      expect(jsonManifest, hasLength(2));
+      expect(jsonManifest[image], equals(<String>[image, image2xVariant]));
+      expect(jsonManifest[imageNonVariant], equals(<String>[imageNonVariant]));
+
+      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
+
+      expect(smcBinManifest, equals(
+          <String, List<Map<String, Object>>>{
+            image: <Map<String, Object>>[
+              <String, String>{
+                'asset': image,
+              },
+              <String, Object>{
+                'asset': image2xVariant,
+                'dpr': 2.0,
+              }
+            ],
+            imageNonVariant: <Map<String, String>>[
+              <String, String>{
+                'asset': imageNonVariant,
+              }
+            ],
+          }
+        )
+      );
     });
 
     testWithoutContext('Asset directories have their subdirectories searched for asset variants', () async {
-      createPubspec(assets: <String>['assets', 'assets/folder']);
+      createPubspec(assets: <String>['assets/', 'assets/folder/']);
 
       const String topLevelImage = 'assets/image.jpg';
       const String secondLevelImage = 'assets/folder/secondLevel.jpg';
@@ -129,14 +160,36 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestFromBundle(bundle);
+      final Map<String, List<String>> manifest = await extractAssetManifestJsonFromBundle(bundle);
       expect(manifest, hasLength(2));
       expect(manifest[topLevelImage], equals(<String>[topLevelImage]));
       expect(manifest[secondLevelImage], equals(<String>[secondLevelImage, secondLevel2xVariant]));
+
+      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
+
+      expect(smcBinManifest, equals(
+          <String, List<Map<String, Object>>>{
+            topLevelImage: <Map<String, Object>>[
+              <String, String>{
+                'asset': topLevelImage,
+              },
+            ],
+            secondLevelImage: <Map<String, Object>>[
+              <String, String>{
+                'asset': secondLevelImage,
+              },
+              <String, Object>{
+                'asset': secondLevel2xVariant,
+                'dpr': 2.0,
+              },
+            ],
+          }
+        )
+      );
     });
 
     testWithoutContext('Asset paths should never be URI-encoded', () async {
-      createPubspec(assets: <String>['assets/normalFolder']);
+      createPubspec(assets: <String>['assets/normalFolder/']);
 
       const String image = 'assets/normalFolder/i have URI-reserved_characters.jpg';
       const String imageVariant = 'assets/normalFolder/3x/i have URI-reserved_characters.jpg';
@@ -163,9 +216,26 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestFromBundle(bundle);
+      final Map<String, List<String>> manifest = await extractAssetManifestJsonFromBundle(bundle);
       expect(manifest, hasLength(1));
       expect(manifest[image], equals(<String>[image, imageVariant]));
+
+      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
+
+      expect(smcBinManifest, equals(
+          <String, List<Map<String, Object>>>{
+            image: <Map<String, Object>>[
+              <String, Object>{
+                'asset': image,
+              },
+              <String, Object>{
+                'asset': imageVariant,
+                'dpr': 3.0
+              },
+            ],
+          }
+        )
+      );
     });
 
     testWithoutContext('Main assets are not included if the file does not exist', () async {
@@ -194,13 +264,25 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestFromBundle(bundle);
+      final Map<String, List<String>> manifest = await extractAssetManifestJsonFromBundle(bundle);
       expect(manifest, hasLength(1));
       expect(manifest['assets/image.png'], equals(<String>[imageVariant]));
+
+      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
+      expect(smcBinManifest, equals(
+          <String, List<Map<String, Object>>>{
+            'assets/image.png': <Map<String, Object>>[
+              <String, Object>{
+                'asset': imageVariant,
+                'dpr': 2.0
+              },
+            ],
+          }
+        )
+      );
     });
   });
 
-
   group('AssetBundle asset variants (with Windows-style filepaths)', () {
     late final Platform platform;
     late final FileSystem fs;
@@ -255,11 +337,36 @@ flutter:
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestFromBundle(bundle);
+      final Map<String, List<String>> manifest = await extractAssetManifestJsonFromBundle(bundle);
 
       expect(manifest, hasLength(2));
       expect(manifest['assets/foo.jpg'], equals(<String>['assets/foo.jpg', 'assets/2x/foo.jpg']));
       expect(manifest['assets/somewhereElse/bar.jpg'], equals(<String>['assets/somewhereElse/bar.jpg', 'assets/somewhereElse/2x/bar.jpg']));
+
+      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
+      expect(smcBinManifest, equals(
+          <String, List<Map<String, Object>>>{
+            'assets/foo.jpg': <Map<String, Object>>[
+              <String, Object>{
+                'asset': 'assets/foo.jpg',
+              },
+              <String, Object>{
+                'asset': 'assets/2x/foo.jpg',
+                'dpr': 2.0,
+              },
+            ],
+            'assets/somewhereElse/bar.jpg': <Map<String, Object>>[
+              <String, Object>{
+                'asset': 'assets/somewhereElse/bar.jpg',
+              },
+              <String, Object>{
+                'asset': 'assets/somewhereElse/2x/bar.jpg',
+                'dpr': 2.0,
+              },
+            ],
+          }
+        )
+      );
     });
   });
 }

From 1183970879cc4de5dd6abe014f93fefbc3d9c30a Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Sat, 3 Jun 2023 19:51:31 -0700
Subject: [PATCH 5/9] fix and tidy up some tests

---
 .../test/services/asset_manifest_test.dart    |  29 +-
 .../asset_bundle_package_test.dart            | 264 +++++++++---------
 .../asset_bundle_variant_test.dart            | 206 +++++++-------
 3 files changed, 255 insertions(+), 244 deletions(-)

diff --git a/packages/flutter/test/services/asset_manifest_test.dart b/packages/flutter/test/services/asset_manifest_test.dart
index 736f62e8d0d1e..11342333ac706 100644
--- a/packages/flutter/test/services/asset_manifest_test.dart
+++ b/packages/flutter/test/services/asset_manifest_test.dart
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:convert';
+
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
@@ -39,7 +41,6 @@ class TestAssetBundle extends AssetBundle {
   }
 }
 
-
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
@@ -72,3 +73,29 @@ void main() {
     expect(manifest.getAssetVariants('invalid asset key'), isNull);
   });
 }
+
+String createAssetManifestJson(Map<String, List<AssetMetadata>> manifest) {
+  final Map<Object, Object> jsonObject = manifest.map(
+    (String key, List<AssetMetadata> value) {
+      final List<String> variants = value.map((AssetMetadata e) => e.key).toList();
+      return MapEntry<String, List<String>>(key, variants);
+    }
+  );
+
+  return json.encode(jsonObject);
+}
+
+ByteData createAssetManifestSmcBin(Map<String, List<AssetMetadata>> manifest) {
+  final Map<Object, Object> smcObject  = manifest.map(
+    (String key, List<AssetMetadata> value) {
+      final List<Object> variants = value.map((AssetMetadata variant) => <String, Object?>{
+        'asset': variant.key,
+        'dpr': variant.targetDevicePixelRatio,
+      }).toList();
+
+      return MapEntry<String, List<Object>>(key, variants);
+    }
+  );
+
+  return const StandardMessageCodec().encodeMessage(smcObject)!;
+}
diff --git a/packages/flutter_tools/test/general.shard/asset_bundle_package_test.dart b/packages/flutter_tools/test/general.shard/asset_bundle_package_test.dart
index c8bb1339efa1b..7220d9c991d25 100644
--- a/packages/flutter_tools/test/general.shard/asset_bundle_package_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_package_test.dart
@@ -16,6 +16,7 @@ import 'package:standard_message_codec/standard_message_codec.dart';
 
 import '../src/common.dart';
 import '../src/context.dart';
+import 'asset_bundle_variant_test.dart';
 
 void main() {
   String fixPath(String path) {
@@ -26,6 +27,7 @@ void main() {
     // rolls into Flutter.
     return path.replaceAll('/', globals.fs.path.separator);
   }
+
   void writePubspecFile(String path, String name, { List<String>? assets }) {
     String assetsSection;
     if (assets == null) {
@@ -65,16 +67,8 @@ $assetsSection
   Future<void> buildAndVerifyAssets(
     List<String> assets,
     List<String> packages,
-    String? expectedJsonAssetManifest,
-    String? expectedBinAssetManifestAsJson, {
-    bool expectExists = true,
-  }) async {
-    Future<String> extractAssetManifestBinFromBundleAsJson(AssetBundle bundle) async {
-      final List<int> manifestBytes = await bundle.entries['AssetManifest.smcbin']!.contentsAsBytes();
-      return json.encode(const StandardMessageCodec().decodeMessage(
-        ByteData.sublistView(Uint8List.fromList(manifestBytes))
-      ));
-    }
+    Map<Object,Object> expectedAssetManifest
+  ) async {
 
     final AssetBundle bundle = AssetBundleFactory.instance.createBundle();
     await bundle.build(packagesPath: '.packages');
@@ -82,28 +76,33 @@ $assetsSection
     for (final String packageName in packages) {
       for (final String asset in assets) {
         final String entryKey = Uri.encodeFull('packages/$packageName/$asset');
-        expect(bundle.entries.containsKey(entryKey), expectExists,
+        expect(bundle.entries, contains(entryKey),
           reason: 'Cannot find key on bundle: $entryKey');
-        if (expectExists) {
-          expect(
-            utf8.decode(await bundle.entries[entryKey]!.contentsAsBytes()),
-            asset,
-          );
-        }
+        expect(
+          utf8.decode(await bundle.entries[entryKey]!.contentsAsBytes()),
+          asset,
+        );
       }
     }
 
-    if (expectExists) {
+    final Map<Object?, Object?> assetManifest =
+      const StandardMessageCodec().decodeMessage(
+        ByteData.sublistView(
+          Uint8List.fromList(
+            await bundle.entries['AssetManifest.smcbin']!.contentsAsBytes()
+          )
+        )
+      ) as Map<Object?, Object?>;
+
       expect(
-        utf8.decode(await bundle.entries['AssetManifest.json']!.contentsAsBytes()),
-        expectedJsonAssetManifest,
+        json.decode(utf8.decode(await bundle.entries['AssetManifest.json']!.contentsAsBytes())),
+        assetManifestBinToJson(expectedAssetManifest),
       );
       expect(
-        await extractAssetManifestBinFromBundleAsJson(bundle),
-        expectedBinAssetManifestAsJson
+        assetManifest,
+        expectedAssetManifest
       );
     }
-  }
 
   void writeAssets(String path, List<String> assets) {
     for (final String asset in assets) {
@@ -190,14 +189,18 @@ $assetsSection
 
       writeAssets('p/p/', assets);
 
-      const String expectedJsonAssetManifest = '{"packages/test_package/a/foo":'
-          '["packages/test_package/a/foo"]}';
-      const String expectedBinAssetManifest = '{"packages/test_package/a/foo":[]}';
+      final Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/foo': <Map<Object, Object>>[
+          <Object, Object>{
+            'asset': 'packages/test_package/a/foo',
+          }
+        ]
+      };
+
       await buildAndVerifyAssets(
         assets,
         <String>['test_package'],
-        expectedJsonAssetManifest,
-        expectedBinAssetManifest
+        expectedAssetManifest,
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -218,14 +221,16 @@ $assetsSection
       final List<String> assets = <String>['a/foo'];
       writeAssets('p/p/lib/', assets);
 
-      const String expectedAssetManifest = '{"packages/test_package/a/foo":'
-          '["packages/test_package/a/foo"]}';
-      const String expectedBinAssetManifest = '{"packages/test_package/a/foo":[]}';
+
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'}
+        ]
+      };
       await buildAndVerifyAssets(
         assets,
         <String>['test_package'],
-        expectedAssetManifest,
-        expectedBinAssetManifest
+        expectedAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -245,25 +250,20 @@ $assetsSection
       final List<String> assets = <String>['a/foo', 'a/2x/foo', 'a/bar'];
       writeAssets('p/p/', assets);
 
-      const String expectedManifest = '{'
-          '"packages/test_package/a/bar":'
-          '["packages/test_package/a/bar"],'
-          '"packages/test_package/a/foo":'
-          '["packages/test_package/a/foo","packages/test_package/a/2x/foo"]'
-          '}';
-
-      const String expectedBinManifest = '{'
-          '"packages/test_package/a/bar":[],'
-          '"packages/test_package/a/foo":'
-          '[{"asset":"packages/test_package/a/2x/foo","dpr":2.0}]'
-          '}';
-
+      const Map<Object, Object> expectedManifest = <Object, Object>{
+        'packages/test_package/a/bar': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/bar'}
+        ],
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'},
+          <String, Object>{'asset': 'packages/test_package/a/2x/foo', 'dpr': 2.0}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assets,
         <String>['test_package'],
         expectedManifest,
-        expectedBinManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -286,17 +286,17 @@ $assetsSection
       final List<String> assets = <String>['a/foo', 'a/2x/foo'];
       writeAssets('p/p/lib/', assets);
 
-      const String expectedManifest = '{"packages/test_package/a/foo":'
-        '["packages/test_package/a/foo","packages/test_package/a/2x/foo"]}';
-
-      const String expectedBinManifest = '{"packages/test_package/a/foo":'
-        '[{"asset":"packages/test_package/a/2x/foo","dpr":2.0}]}';
+      const Map<Object, Object> expectedManifest = <Object, Object>{
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'},
+          <String, Object>{'asset': 'packages/test_package/a/2x/foo', 'dpr': 2.0}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assets,
         <String>['test_package'],
         expectedManifest,
-        expectedBinManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -316,19 +316,19 @@ $assetsSection
       );
 
       writeAssets('p/p/', assets);
-      const String expectedAssetManifest =
-          '{"packages/test_package/a/bar":["packages/test_package/a/bar"],'
-          '"packages/test_package/a/foo":["packages/test_package/a/foo"]}';
-      const String expectedBinAssetManifest =
-          '{"packages/test_package/a/bar":[],'
-          '"packages/test_package/a/foo":[]}';
-
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/bar': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/bar'}
+        ],
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assets,
         <String>['test_package'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -354,18 +354,19 @@ $assetsSection
       );
 
       writeAssets('p/p/lib/', assets);
-      const String expectedAssetManifest =
-          '{"packages/test_package/a/bar":["packages/test_package/a/bar"],'
-          '"packages/test_package/a/foo":["packages/test_package/a/foo"]}';
-      const String expectedBinAssetManifest =
-          '{"packages/test_package/a/bar":[],'
-          '"packages/test_package/a/foo":[]}';
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/bar': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/bar'}
+        ],
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assets,
         <String>['test_package'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -393,22 +394,21 @@ $assetsSection
       writeAssets('p/p/', assets);
       writeAssets('p2/p/', assets);
 
-      const String expectedAssetManifest =
-          '{"packages/test_package/a/foo":'
-          '["packages/test_package/a/foo","packages/test_package/a/2x/foo"],'
-          '"packages/test_package2/a/foo":'
-          '["packages/test_package2/a/foo","packages/test_package2/a/2x/foo"]}';
-      const String expectedBinAssetManifest =
-          '{"packages/test_package/a/foo":'
-          '[{"asset":"packages/test_package/a/2x/foo","dpr":2.0}],'
-          '"packages/test_package2/a/foo":'
-          '[{"asset":"packages/test_package2/a/2x/foo","dpr":2.0}]}';
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'},
+          <String, Object>{'asset': 'packages/test_package/a/2x/foo', 'dpr': 2.0}
+        ],
+        'packages/test_package2/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package2/a/foo'},
+          <String, Object>{'asset': 'packages/test_package2/a/2x/foo', 'dpr': 2.0}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assets,
         <String>['test_package', 'test_package2'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -439,23 +439,21 @@ $assetsSection
       writeAssets('p/p/lib/', assets);
       writeAssets('p2/p/lib/', assets);
 
-      const String expectedAssetManifest =
-          '{"packages/test_package/a/foo":'
-          '["packages/test_package/a/foo","packages/test_package/a/2x/foo"],'
-          '"packages/test_package2/a/foo":'
-          '["packages/test_package2/a/foo","packages/test_package2/a/2x/foo"]}';
-
-      const String expectedBinAssetManifest =
-          '{"packages/test_package/a/foo":'
-          '[{"asset":"packages/test_package/a/2x/foo","dpr":2.0}],'
-          '"packages/test_package2/a/foo":'
-          '[{"asset":"packages/test_package2/a/2x/foo","dpr":2.0}]}';
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'},
+          <String, Object>{'asset': 'packages/test_package/a/2x/foo', 'dpr': 2.0}
+        ],
+        'packages/test_package2/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package2/a/foo'},
+          <String, Object>{'asset': 'packages/test_package2/a/2x/foo', 'dpr': 2.0}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assets,
         <String>['test_package', 'test_package2'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -482,18 +480,17 @@ $assetsSection
       final List<String> assets = <String>['a/foo', 'a/2x/foo'];
       writeAssets('p2/p/lib/', assets);
 
-      const String expectedAssetManifest =
-          '{"packages/test_package2/a/foo":'
-          '["packages/test_package2/a/foo","packages/test_package2/a/2x/foo"]}';
-      const String expectedBinAssetManifest =
-          '{"packages/test_package2/a/foo":'
-          '[{"asset":"packages/test_package2/a/2x/foo","dpr":2.0}]}';
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package2/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package2/a/foo'},
+          <String, Object>{'asset': 'packages/test_package2/a/2x/foo', 'dpr': 2.0}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assets,
         <String>['test_package2'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -513,18 +510,19 @@ $assetsSection
     );
 
     writeAssets('p/p/', assets);
-    const String expectedAssetManifest =
-        '{"packages/test_package/a/foo":["packages/test_package/a/foo"],'
-        '"packages/test_package/a/foo [x]":["packages/test_package/a/foo [x]"]}';
-    const String expectedBinAssetManifest =
-        '{"packages/test_package/a/foo":[],'
-        '"packages/test_package/a/foo [x]":[]}';
+    const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+      'packages/test_package/a/foo': <Map<String, Object>>[
+        <String, Object>{'asset': 'packages/test_package/a/foo'}
+      ],
+      'packages/test_package/a/foo [x]': <Map<String, Object>>[
+        <String, Object>{'asset': 'packages/test_package/a/foo [x]'}
+      ]
+    };
 
     await buildAndVerifyAssets(
       assets,
       <String>['test_package'],
       expectedAssetManifest,
-      expectedBinAssetManifest
     );
   }, overrides: <Type, Generator>{
     FileSystem: () => testFileSystem,
@@ -546,18 +544,19 @@ $assetsSection
       );
 
       writeAssets('p/p/', assetsOnDisk);
-      const String expectedAssetManifest =
-          '{"packages/test_package/a/bar":["packages/test_package/a/bar"],'
-          '"packages/test_package/a/foo":["packages/test_package/a/foo"]}';
-      const String expectedBinAssetManifest =
-          '{"packages/test_package/a/bar":[],'
-          '"packages/test_package/a/foo":[]}';
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/bar': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/bar'}
+        ],
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assetsOnDisk,
         <String>['test_package'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -578,18 +577,19 @@ $assetsSection
       );
 
       writeAssets('p/p/', assetsOnDisk);
-      const String expectedAssetManifest =
-          '{"packages/test_package/a/foo":["packages/test_package/a/foo"],'
-          '"packages/test_package/abc/bar":["packages/test_package/abc/bar"]}';
-      const String expectedBinAssetManifest =
-          '{"packages/test_package/a/foo":[],'
-          '"packages/test_package/abc/bar":[]}';
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'}
+        ],
+        'packages/test_package/abc/bar': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/abc/bar'}
+        ]
+      };
 
       await buildAndVerifyAssets(
         assetsOnDisk,
         <String>['test_package'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -637,16 +637,16 @@ $assetsSection
       );
 
       writeAssets('p/p/', assetsOnDisk);
-      const String expectedAssetManifest =
-          '{"packages/test_package/a/foo":["packages/test_package/a/foo","packages/test_package/a/2x/foo"]}';
-      const String expectedBinAssetManifest =
-          '{"packages/test_package/a/foo":[{"asset":"packages/test_package/a/2x/foo","dpr":2.0}]}';
-
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{
+        'packages/test_package/a/foo': <Map<String, Object>>[
+          <String, Object>{'asset': 'packages/test_package/a/foo'},
+          <String, Object>{'asset': 'packages/test_package/a/2x/foo', 'dpr': 2.0}
+        ]
+      };
       await buildAndVerifyAssets(
         assetsOnDisk,
         <String>['test_package'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -667,15 +667,12 @@ $assetsSection
       );
 
       writeAssets('p/p/', assetsOnDisk);
-      const String expectedAssetManifest = '{}';
-      const String expectedBinAssetManifest = '{}';
-
+      const Map<Object, Object> expectedAssetManifest = <Object, Object>{};
 
       await buildAndVerifyAssets(
         assetOnManifest,
         <String>['test_package'],
         expectedAssetManifest,
-        expectedBinAssetManifest
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
@@ -694,13 +691,8 @@ $assetsSection
         assets: assetOnManifest,
       );
 
-      await buildAndVerifyAssets(
-        assetOnManifest,
-        <String>['test_package'],
-        null,
-        null,
-        expectExists: false,
-      );
+    final AssetBundle bundle = AssetBundleFactory.instance.createBundle();
+    await bundle.build(packagesPath: '.packages');
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
       ProcessManager: () => FakeProcessManager.any(),
diff --git a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
index d09eaf89172ae..94937b6ca9d03 100644
--- a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
@@ -102,32 +102,27 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
       );
 
       final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
-
-      expect(jsonManifest, hasLength(2));
-      expect(jsonManifest[image], equals(<String>[image, image2xVariant]));
-      expect(jsonManifest[imageNonVariant], equals(<String>[imageNonVariant]));
-
       final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
 
-      expect(smcBinManifest, equals(
-          <String, List<Map<String, Object>>>{
-            image: <Map<String, Object>>[
-              <String, String>{
-                'asset': image,
-              },
-              <String, Object>{
-                'asset': image2xVariant,
-                'dpr': 2.0,
-              }
-            ],
-            imageNonVariant: <Map<String, String>>[
-              <String, String>{
-                'asset': imageNonVariant,
-              }
-            ],
+      final Map<String, List<Map<String, Object>>> expectedAssetManifest = <String, List<Map<String, Object>>>{
+        image: <Map<String, Object>>[
+          <String, String>{
+            'asset': image,
+          },
+          <String, Object>{
+            'asset': image2xVariant,
+            'dpr': 2.0,
           }
-        )
-      );
+        ],
+        imageNonVariant: <Map<String, String>>[
+          <String, String>{
+            'asset': imageNonVariant,
+          }
+        ],
+      };
+
+      expect(smcBinManifest, equals(expectedAssetManifest));
+      expect(jsonManifest, equals(assetManifestBinToJson(expectedAssetManifest)));
     });
 
     testWithoutContext('Asset directories have their subdirectories searched for asset variants', () async {
@@ -160,32 +155,31 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestJsonFromBundle(bundle);
-      expect(manifest, hasLength(2));
-      expect(manifest[topLevelImage], equals(<String>[topLevelImage]));
-      expect(manifest[secondLevelImage], equals(<String>[secondLevelImage, secondLevel2xVariant]));
+      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
+      expect(jsonManifest, hasLength(2));
+      expect(jsonManifest[topLevelImage], equals(<String>[topLevelImage]));
+      expect(jsonManifest[secondLevelImage], equals(<String>[secondLevelImage, secondLevel2xVariant]));
 
       final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
 
-      expect(smcBinManifest, equals(
-          <String, List<Map<String, Object>>>{
-            topLevelImage: <Map<String, Object>>[
-              <String, String>{
-                'asset': topLevelImage,
-              },
-            ],
-            secondLevelImage: <Map<String, Object>>[
-              <String, String>{
-                'asset': secondLevelImage,
-              },
-              <String, Object>{
-                'asset': secondLevel2xVariant,
-                'dpr': 2.0,
-              },
-            ],
-          }
-        )
-      );
+      final Map<String, List<Map<String, Object>>> expectedAssetManifest = <String, List<Map<String, Object>>>{
+        topLevelImage: <Map<String, Object>>[
+          <String, String>{
+            'asset': topLevelImage,
+          },
+        ],
+        secondLevelImage: <Map<String, Object>>[
+          <String, String>{
+            'asset': secondLevelImage,
+          },
+          <String, Object>{
+            'asset': secondLevel2xVariant,
+            'dpr': 2.0,
+          },
+        ],
+      };
+      expect(jsonManifest, equals(assetManifestBinToJson(expectedAssetManifest)));
+      expect(smcBinManifest, equals(expectedAssetManifest));
     });
 
     testWithoutContext('Asset paths should never be URI-encoded', () async {
@@ -216,26 +210,23 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestJsonFromBundle(bundle);
-      expect(manifest, hasLength(1));
-      expect(manifest[image], equals(<String>[image, imageVariant]));
-
+      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
       final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
 
-      expect(smcBinManifest, equals(
-          <String, List<Map<String, Object>>>{
-            image: <Map<String, Object>>[
-              <String, Object>{
-                'asset': image,
-              },
-              <String, Object>{
-                'asset': imageVariant,
-                'dpr': 3.0
-              },
-            ],
-          }
-        )
-      );
+      final Map<String, List<Map<String, Object>>> expectedAssetManifest = <String, List<Map<String, Object>>>{
+        image: <Map<String, Object>>[
+          <String, Object>{
+            'asset': image,
+          },
+          <String, Object>{
+            'asset': imageVariant,
+            'dpr': 3.0
+          },
+        ],
+      };
+
+      expect(jsonManifest, equals(assetManifestBinToJson(expectedAssetManifest)));
+      expect(smcBinManifest, equals(expectedAssetManifest));
     });
 
     testWithoutContext('Main assets are not included if the file does not exist', () async {
@@ -264,22 +255,19 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestJsonFromBundle(bundle);
-      expect(manifest, hasLength(1));
-      expect(manifest['assets/image.png'], equals(<String>[imageVariant]));
-
+      final Map<String, List<Map<String, Object>>> expectedManifest = <String, List<Map<String, Object>>>{
+        'assets/image.png': <Map<String, Object>>[
+          <String, Object>{
+            'asset': imageVariant,
+            'dpr': 2.0
+          },
+        ],
+      };
+      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
       final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
-      expect(smcBinManifest, equals(
-          <String, List<Map<String, Object>>>{
-            'assets/image.png': <Map<String, Object>>[
-              <String, Object>{
-                'asset': imageVariant,
-                'dpr': 2.0
-              },
-            ],
-          }
-        )
-      );
+
+      expect(jsonManifest, equals(assetManifestBinToJson(expectedManifest)));
+      expect(smcBinManifest, equals(expectedManifest));
     });
   });
 
@@ -337,36 +325,40 @@ flutter:
         flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
       );
 
-      final Map<String, List<String>> manifest = await extractAssetManifestJsonFromBundle(bundle);
-
-      expect(manifest, hasLength(2));
-      expect(manifest['assets/foo.jpg'], equals(<String>['assets/foo.jpg', 'assets/2x/foo.jpg']));
-      expect(manifest['assets/somewhereElse/bar.jpg'], equals(<String>['assets/somewhereElse/bar.jpg', 'assets/somewhereElse/2x/bar.jpg']));
+      final Map<String, List<Map<String, Object>>> expectedAssetManifest = <String, List<Map<String, Object>>>{
+        'assets/foo.jpg': <Map<String, Object>>[
+          <String, Object>{
+            'asset': 'assets/foo.jpg',
+          },
+          <String, Object>{
+            'asset': 'assets/2x/foo.jpg',
+            'dpr': 2.0,
+          },
+        ],
+        'assets/somewhereElse/bar.jpg': <Map<String, Object>>[
+          <String, Object>{
+            'asset': 'assets/somewhereElse/bar.jpg',
+          },
+          <String, Object>{
+            'asset': 'assets/somewhereElse/2x/bar.jpg',
+            'dpr': 2.0,
+          },
+        ],
+      };
 
+      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
       final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
-      expect(smcBinManifest, equals(
-          <String, List<Map<String, Object>>>{
-            'assets/foo.jpg': <Map<String, Object>>[
-              <String, Object>{
-                'asset': 'assets/foo.jpg',
-              },
-              <String, Object>{
-                'asset': 'assets/2x/foo.jpg',
-                'dpr': 2.0,
-              },
-            ],
-            'assets/somewhereElse/bar.jpg': <Map<String, Object>>[
-              <String, Object>{
-                'asset': 'assets/somewhereElse/bar.jpg',
-              },
-              <String, Object>{
-                'asset': 'assets/somewhereElse/2x/bar.jpg',
-                'dpr': 2.0,
-              },
-            ],
-          }
-        )
-      );
+
+      expect(jsonManifest, equals(assetManifestBinToJson(expectedAssetManifest)));
+      expect(smcBinManifest, equals(expectedAssetManifest));
     });
   });
 }
+
+Map<Object, Object> assetManifestBinToJson(Map<Object, Object> manifest) {
+  List<Object> convertList(List<Object> variants) => variants
+    .map((Object variant) => (variant as Map<Object?, Object?>)['asset']!)
+    .toList();
+
+  return manifest.map((Object key, Object value) => MapEntry<Object, Object>(key, convertList(value as List<Object>)));
+}

From 3dde74bd5d8bedaf83ad51a82790393cec03e62a Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Sat, 3 Jun 2023 20:51:40 -0700
Subject: [PATCH 6/9] fix some tests

---
 .../test/painting/image_resolution_test.dart  | 20 ++++++------
 .../test/widgets/image_resolution_test.dart   | 32 +++++++++----------
 2 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/packages/flutter/test/painting/image_resolution_test.dart b/packages/flutter/test/painting/image_resolution_test.dart
index fd64c06bd01c0..eacbe36740b45 100644
--- a/packages/flutter/test/painting/image_resolution_test.dart
+++ b/packages/flutter/test/painting/image_resolution_test.dart
@@ -160,15 +160,17 @@ void main() {
       double chosenAssetRatio,
       String expectedAssetPath,
     ) {
-      final Map<String, List<Map<Object?, Object?>>> assetBundleMap =
-        <String, List<Map<Object?, Object?>>>{};
-
-      final Map<Object?, Object?> mainAssetVariantManifestEntry = <Object?, Object?>{};
-      mainAssetVariantManifestEntry['asset'] = variantPath;
-      mainAssetVariantManifestEntry['dpr'] = 3.0;
-      assetBundleMap[mainAssetPath] = <Map<Object?, Object?>>[mainAssetVariantManifestEntry];
-
-      final TestAssetBundle testAssetBundle = TestAssetBundle(assetBundleMap);
+      const Map<String, List<Map<Object?, Object?>>> assetManifest =
+          <String, List<Map<Object?, Object?>>>{
+        'assets/normalFolder/normalFile.png': <Map<Object?, Object?>>[
+          <Object?, Object?>{'asset': 'assets/normalFolder/normalFile.png'},
+          <Object?, Object?>{
+            'asset': 'assets/normalFolder/3.0x/normalFile.png',
+            'dpr': 3.0
+          },
+        ]
+      };
+      final TestAssetBundle testAssetBundle = TestAssetBundle(assetManifest);
 
       final AssetImage assetImage = AssetImage(
         mainAssetPath,
diff --git a/packages/flutter/test/widgets/image_resolution_test.dart b/packages/flutter/test/widgets/image_resolution_test.dart
index dedd14adcd793..620cbdff8f8ef 100644
--- a/packages/flutter/test/widgets/image_resolution_test.dart
+++ b/packages/flutter/test/widgets/image_resolution_test.dart
@@ -19,16 +19,15 @@ import '../image_data.dart';
 ByteData testByteData(double scale) => ByteData(8)..setFloat64(0, scale);
 double scaleOf(ByteData data) => data.getFloat64(0);
 
-final Map<Object?, Object?> testManifest = json.decode('''
-{
-  "assets/image.png" : [
-    {"asset": "assets/1.5x/image.png", "dpr": 1.5},
-    {"asset": "assets/2.0x/image.png", "dpr": 2.0},
-    {"asset": "assets/3.0x/image.png", "dpr": 3.0},
-    {"asset": "assets/4.0x/image.png", "dpr": 4.0}
-  ]
-}
-''') as Map<Object?, Object?>;
+final Map<Object?, Object?> testManifest = <Object?, Object?>{
+  'assets/image.png' : <Map<String, Object>>[
+    <String, String>{'asset': 'assets/image.png'},
+    <String, Object>{'asset': 'assets/1.5x/image.png', 'dpr': 1.5},
+    <String, Object>{'asset': 'assets/2.0x/image.png', 'dpr': 2.0},
+    <String, Object>{'asset': 'assets/3.0x/image.png', 'dpr': 3.0},
+    <String, Object>{'asset': 'assets/4.0x/image.png', 'dpr': 4.0}
+  ],
+};
 
 class TestAssetBundle extends CachingAssetBundle {
   TestAssetBundle({ required Map<Object?, Object?> manifest }) {
@@ -303,13 +302,12 @@ void main() {
   // if higher resolution assets are not available we will pick the best
   // available.
   testWidgets('Low-resolution assets', (WidgetTester tester) async {
-    final Map<Object?, Object?> manifest = json.decode('''
-      {
-        "assets/image.png" : [
-          {"asset": "assets/1.5x/image.png", "dpr": 1.5}
-        ]
-      }
-    ''') as Map<Object?, Object?>;
+    const Map<Object?, Object?> manifest = <Object?, Object?>{
+      'assets/image.png': <Map<String, Object>>[
+        <String, Object>{'asset': 'assets/image.png'},
+        <String, Object>{'asset': 'assets/1.5x/image.png', 'dpr': 1.5},
+      ],
+    };
     final AssetBundle bundle = TestAssetBundle(manifest: manifest);
 
     Future<void> testRatio({required double ratio, required double expectedScale}) async {

From c1462195f9d932b3a68646493c7f9813573f48c0 Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Sat, 3 Jun 2023 22:26:32 -0700
Subject: [PATCH 7/9] fix test

---
 packages/flutter/lib/src/painting/image_resolution.dart   | 6 +-----
 packages/flutter/test/painting/image_resolution_test.dart | 2 --
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/packages/flutter/lib/src/painting/image_resolution.dart b/packages/flutter/lib/src/painting/image_resolution.dart
index 58d3acf71af3d..2644a05f72583 100644
--- a/packages/flutter/lib/src/painting/image_resolution.dart
+++ b/packages/flutter/lib/src/painting/image_resolution.dart
@@ -327,14 +327,10 @@ class AssetImage extends AssetBundleImageProvider {
   }
 
   AssetMetadata _chooseVariant(String mainAssetKey, ImageConfiguration config, Iterable<AssetMetadata>? candidateVariants) {
-    if (candidateVariants == null) {
+    if (candidateVariants == null || candidateVariants.isEmpty || config.devicePixelRatio == null) {
       return AssetMetadata(key: mainAssetKey, targetDevicePixelRatio: null, main: true);
     }
 
-    if (config.devicePixelRatio == null) {
-      return candidateVariants.firstWhere((AssetMetadata variant) => variant.main);
-    }
-
     final SplayTreeMap<double, AssetMetadata> candidatesByDevicePixelRatio =
       SplayTreeMap<double, AssetMetadata>();
     for (final AssetMetadata candidate in candidateVariants) {
diff --git a/packages/flutter/test/painting/image_resolution_test.dart b/packages/flutter/test/painting/image_resolution_test.dart
index eacbe36740b45..bfc9c6ede13f6 100644
--- a/packages/flutter/test/painting/image_resolution_test.dart
+++ b/packages/flutter/test/painting/image_resolution_test.dart
@@ -43,8 +43,6 @@ void main() {
       final Map<String, List<Map<Object?, Object?>>> assetBundleMap =
         <String, List<Map<Object?, Object?>>>{};
 
-      assetBundleMap[mainAssetPath] = <Map<Object?, Object?>>[];
-
       final AssetImage assetImage = AssetImage(
         mainAssetPath,
         bundle: TestAssetBundle(assetBundleMap),

From 5c773935b5c2015d04b2b67e1e0a2208c77a88b4 Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Sat, 3 Jun 2023 22:51:57 -0700
Subject: [PATCH 8/9] lint

---
 .../asset_bundle_package_test.dart            | 40 +++++++++++--------
 .../asset_bundle_variant_test.dart            | 12 +++---
 2 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/packages/flutter_tools/test/general.shard/asset_bundle_package_test.dart b/packages/flutter_tools/test/general.shard/asset_bundle_package_test.dart
index 7220d9c991d25..c45d4e0647ea9 100644
--- a/packages/flutter_tools/test/general.shard/asset_bundle_package_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_package_test.dart
@@ -16,7 +16,6 @@ import 'package:standard_message_codec/standard_message_codec.dart';
 
 import '../src/common.dart';
 import '../src/context.dart';
-import 'asset_bundle_variant_test.dart';
 
 void main() {
   String fixPath(String path) {
@@ -64,6 +63,14 @@ $assetsSection
       ..writeAsStringSync(packages);
   }
 
+  Map<Object, Object> assetManifestBinToJson(Map<Object, Object> manifest) {
+    List<Object> convertList(List<Object> variants) => variants
+      .map((Object variant) => (variant as Map<Object?, Object?>)['asset']!)
+      .toList();
+
+    return manifest.map((Object key, Object value) => MapEntry<Object, Object>(key, convertList(value as List<Object>)));
+  }
+
   Future<void> buildAndVerifyAssets(
     List<String> assets,
     List<String> packages,
@@ -85,24 +92,23 @@ $assetsSection
       }
     }
 
-    final Map<Object?, Object?> assetManifest =
-      const StandardMessageCodec().decodeMessage(
-        ByteData.sublistView(
-          Uint8List.fromList(
-            await bundle.entries['AssetManifest.smcbin']!.contentsAsBytes()
-          )
+    final Map<Object?, Object?> assetManifest = const StandardMessageCodec().decodeMessage(
+      ByteData.sublistView(
+        Uint8List.fromList(
+          await bundle.entries['AssetManifest.smcbin']!.contentsAsBytes()
         )
-      ) as Map<Object?, Object?>;
+      )
+    ) as Map<Object?, Object?>;
 
-      expect(
-        json.decode(utf8.decode(await bundle.entries['AssetManifest.json']!.contentsAsBytes())),
-        assetManifestBinToJson(expectedAssetManifest),
-      );
-      expect(
-        assetManifest,
-        expectedAssetManifest
-      );
-    }
+    expect(
+      json.decode(utf8.decode(await bundle.entries['AssetManifest.json']!.contentsAsBytes())),
+      assetManifestBinToJson(expectedAssetManifest),
+    );
+    expect(
+      assetManifest,
+      expectedAssetManifest
+    );
+  }
 
   void writeAssets(String path, List<String> assets) {
     for (final String asset in assets) {
diff --git a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
index 94937b6ca9d03..93c1e5c21c062 100644
--- a/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart
@@ -122,7 +122,7 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
       };
 
       expect(smcBinManifest, equals(expectedAssetManifest));
-      expect(jsonManifest, equals(assetManifestBinToJson(expectedAssetManifest)));
+      expect(jsonManifest, equals(_assetManifestBinToJson(expectedAssetManifest)));
     });
 
     testWithoutContext('Asset directories have their subdirectories searched for asset variants', () async {
@@ -178,7 +178,7 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
           },
         ],
       };
-      expect(jsonManifest, equals(assetManifestBinToJson(expectedAssetManifest)));
+      expect(jsonManifest, equals(_assetManifestBinToJson(expectedAssetManifest)));
       expect(smcBinManifest, equals(expectedAssetManifest));
     });
 
@@ -225,7 +225,7 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
         ],
       };
 
-      expect(jsonManifest, equals(assetManifestBinToJson(expectedAssetManifest)));
+      expect(jsonManifest, equals(_assetManifestBinToJson(expectedAssetManifest)));
       expect(smcBinManifest, equals(expectedAssetManifest));
     });
 
@@ -266,7 +266,7 @@ ${assets.map((String entry) => '    - $entry').join('\n')}
       final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
       final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
 
-      expect(jsonManifest, equals(assetManifestBinToJson(expectedManifest)));
+      expect(jsonManifest, equals(_assetManifestBinToJson(expectedManifest)));
       expect(smcBinManifest, equals(expectedManifest));
     });
   });
@@ -349,13 +349,13 @@ flutter:
       final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
       final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);
 
-      expect(jsonManifest, equals(assetManifestBinToJson(expectedAssetManifest)));
+      expect(jsonManifest, equals(_assetManifestBinToJson(expectedAssetManifest)));
       expect(smcBinManifest, equals(expectedAssetManifest));
     });
   });
 }
 
-Map<Object, Object> assetManifestBinToJson(Map<Object, Object> manifest) {
+Map<Object, Object> _assetManifestBinToJson(Map<Object, Object> manifest) {
   List<Object> convertList(List<Object> variants) => variants
     .map((Object variant) => (variant as Map<Object?, Object?>)['asset']!)
     .toList();

From 56ab42cb2abb44540e89c702b5514ef49008a66c Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Tue, 6 Jun 2023 10:39:50 -0700
Subject: [PATCH 9/9] Update
 packages/flutter/lib/src/services/asset_manifest.dart

Co-authored-by: Jonah Williams <jonahwilliams@google.com>
---
 packages/flutter/lib/src/services/asset_manifest.dart | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/flutter/lib/src/services/asset_manifest.dart b/packages/flutter/lib/src/services/asset_manifest.dart
index 7451782eaad34..1fb06dba8a6cd 100644
--- a/packages/flutter/lib/src/services/asset_manifest.dart
+++ b/packages/flutter/lib/src/services/asset_manifest.dart
@@ -78,7 +78,7 @@ class _AssetManifestBin implements AssetManifest {
           final Object? dpr = data['dpr'];
           return AssetMetadata(
             key: data['asset']! as String,
-            targetDevicePixelRatio: dpr == null ? null : dpr as double,
+            targetDevicePixelRatio: dpr as double?,
             main: key == asset,
           );
         })