flutter · auto-submit · Jun 7, 2023 · Jun 2, 2023 · Jun 3, 2023 · Jun 3, 2023
diff --git 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/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);
 }
 
@@ -73,22 +73,21 @@ 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 as double?,
+            main: key == asset,
+          );
+        })
         .toList();
 
       _data.remove(key);
     }
 
-    final AssetMetadata mainAsset = AssetMetadata(key: key,
-      targetDevicePixelRatio: null,
-      main: true
-    );
-
-    return <AssetMetadata>[mainAsset, ..._typeCastedData[key]!];
+    return _typeCastedData[key]!;
   }
 
   @override

diff --git 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),
@@ -160,15 +158,17 @@ 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/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';
 
@@ -11,12 +13,19 @@ 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)!;
@@ -32,7 +41,6 @@ class TestAssetBundle extends AssetBundle {
   }
 }
 
-
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
@@ -65,3 +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/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 {

diff --git 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;