Support for building dynamic patches in AOT mode. (#27672)

packages/flutter_tools/lib/src/android/gradle.dart

@@ -503,13 +503,21 @@ Future<void> _buildGradleProjectV2(
 
       final Archive update = Archive();
       for (ArchiveFile newFile in newApk) {
-        if (!newFile.isFile || !newFile.name.startsWith('assets/flutter_assets/'))
+        if (!newFile.isFile)
+          continue;
+
+        // Ignore changes to signature manifests.
+        if (newFile.name.startsWith('META-INF/'))
           continue;
 
         final ArchiveFile oldFile = oldApk.findFile(newFile.name);
         if (oldFile != null && oldFile.crc32 == newFile.crc32)
           continue;
 
+        // Only allow changes under assets/.
+        if (!newFile.name.startsWith('assets/'))
+          throwToolExit("Error: Dynamic patching doesn't support changes to ${newFile.name}.");
+
         final String name = fs.path.relative(newFile.name, from: 'assets/');
         update.addFile(ArchiveFile(name, newFile.content.length, newFile.content));
       }
@@ -527,11 +535,21 @@ Future<void> _buildGradleProjectV2(
         printStatus('No changes detected, creating rollback patch.');
       }
 
-      final ArchiveFile oldFile = oldApk.findFile('assets/flutter_assets/isolate_snapshot_data');
-      if (oldFile == null)
-        throwToolExit('Error: Could not find baseline assets/flutter_assets/isolate_snapshot_data.');
+      final List<String> checksumFiles = <String>[
+        'assets/isolate_snapshot_data',
+        'assets/isolate_snapshot_instr',
+        'assets/flutter_assets/isolate_snapshot_data',
+      ];
+
+      int baselineChecksum = 0;
+      for (String fn in checksumFiles) {
+        final ArchiveFile oldFile = oldApk.findFile(fn);
+        if (oldFile != null)
+          baselineChecksum = getCrc32(oldFile.content, baselineChecksum);
+      }
+      if (baselineChecksum == 0)
+        throwToolExit('Error: Could not find baseline VM snapshot.');
 
-      final int baselineChecksum = getCrc32(oldFile.content);
       final Map<String, dynamic> manifest = <String, dynamic>{
         'baselineChecksum': baselineChecksum,
         'buildNumber': package.versionCode,

packages/flutter_tools/lib/src/base/build.dart

@@ -440,6 +440,15 @@ class JITSnapshotter {
           }
         }
       }
+
+      {
+        final ArchiveFile af = baselinePkg.findFile(
+            fs.path.join('assets/flutter_assets/vm_snapshot_instr'));
+        if (af != null) {
+          printError('Error: Invalid baseline package ${baselineApk.path}.');
+          return 1;
+        }
+      }
     }
 
     final String depfilePath = fs.path.join(outputDir.path, 'snapshot.d');

packages/flutter_tools/lib/src/base/user_messages.dart

@@ -229,9 +229,7 @@ class UserMessages {
       'https://github.com/flutter/flutter/blob/master/examples/flutter_gallery/pubspec.yaml\n';
   String flutterTargetFileMissing(String path) => 'Target file "$path" not found.';
   String get flutterBasePatchFlagsExclusive => 'Error: Only one of --baseline, --patch is allowed.';
-  String get flutterBaselineRequiresDynamic => 'Error: --baseline is allowed only when --dynamic is specified.';
   String get flutterBaselineRequiresTraceFile => 'Error: --baseline requires --compilation-trace-file to be specified.';
-  String get flutterPatchRequiresDynamic => 'Error: --patch is allowed only when --dynamic is specified.';
   String get flutterPatchRequiresTraceFile => 'Error: --patch requires --compilation-trace-file to be specified.';
 
   // Messages used in FlutterCommandRunner

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -647,8 +647,6 @@ abstract class FlutterCommand extends Command<void> {
         throw ToolExit(userMessages.flutterTargetFileMissing(targetPath));
     }
 
-    final bool dynamicFlag = argParser.options.containsKey('dynamic')
-        ? argResults['dynamic'] : false;
     final String compilationTraceFilePath = argParser.options.containsKey('compilation-trace-file')
         ? argResults['compilation-trace-file'] : null;
     final bool createBaseline = argParser.options.containsKey('baseline')
@@ -658,12 +656,8 @@ abstract class FlutterCommand extends Command<void> {
 
     if (createBaseline && createPatch)
       throw ToolExit(userMessages.flutterBasePatchFlagsExclusive);
-    if (createBaseline && !dynamicFlag)
-      throw ToolExit(userMessages.flutterBaselineRequiresDynamic);
     if (createBaseline && compilationTraceFilePath == null)
       throw ToolExit(userMessages.flutterBaselineRequiresTraceFile);
-    if (createPatch && !dynamicFlag)
-      throw ToolExit(userMessages.flutterPatchRequiresDynamic);
     if (createPatch && compilationTraceFilePath == null)
       throw ToolExit(userMessages.flutterPatchRequiresTraceFile);
   }