fix(shorebird_cli): gracefully handle failure to generate an aab diff (#922)

packages/shorebird_cli/lib/src/archive_analysis/aab_differ.dart

@@ -2,8 +2,10 @@ import 'dart:convert';
 import 'dart:io';
 
 import 'package:archive/archive_io.dart';
+import 'package:collection/collection.dart';
 import 'package:shorebird_cli/src/archive_analysis/android_archive_differ.dart';
 import 'package:shorebird_cli/src/archive_analysis/archive_analysis.dart';
+import 'package:shorebird_cli/src/archive_analysis/archive_differ.dart';
 import 'package:shorebird_cli/src/archive_analysis/mf_reader.dart';
 
 /// Finds differences between two AABs.
@@ -45,10 +47,14 @@ class AabDiffer extends AndroidArchiveDiffer {
   String _metaInfMfContent(File aab) {
     final inputStream = InputFileStream(aab.path);
     final archive = ZipDecoder().decodeBuffer(inputStream);
-    return utf8.decode(
-      archive.files
-          .firstWhere((file) => file.name == 'META-INF/MANIFEST.MF')
-          .content as List<int>,
+    final manifestFile = archive.files.firstWhereOrNull(
+      (file) => file.name == 'META-INF/MANIFEST.MF',
     );
+
+    if (manifestFile == null) {
+      throw DiffFailedException();
+    }
+
+    return utf8.decode(manifestFile.content as List<int>);
   }
 }

packages/shorebird_cli/lib/src/archive_analysis/archive_differ.dart

@@ -1,5 +1,8 @@
 import 'package:shorebird_cli/src/archive_analysis/archive_analysis.dart';
 
+/// Thrown when an [ArchiveDiffer] fails to generate a [FileSetDiff].
+class DiffFailedException implements Exception {}
+
 /// Computes content differences between two archives.
 abstract class ArchiveDiffer {
   /// Files that have been added, removed, or that have changed between the

packages/shorebird_cli/lib/src/commands/patch/patch_android_command.dart

@@ -5,6 +5,7 @@ import 'package:http/http.dart' as http;
 import 'package:mason_logger/mason_logger.dart';
 import 'package:path/path.dart' as p;
 import 'package:shorebird_cli/src/archive_analysis/archive_analysis.dart';
+import 'package:shorebird_cli/src/archive_analysis/archive_differ.dart';
 import 'package:shorebird_cli/src/cache.dart';
 import 'package:shorebird_cli/src/code_push_client_wrapper.dart';
 import 'package:shorebird_cli/src/command.dart';
@@ -242,10 +243,19 @@ https://github.com/shorebirdtech/shorebird/issues/472
 
     downloadReleaseArtifactProgress.complete();
 
-    final contentDiffs = _aabDiffer.changedFiles(
-      releaseAabPath,
-      bundlePath,
-    );
+    FileSetDiff contentDiffs;
+    try {
+      contentDiffs = _aabDiffer.changedFiles(
+        releaseAabPath,
+        bundlePath,
+      );
+    } on DiffFailedException catch (_) {
+      logger.warn(
+        '''
+Could not determine whether patch contains asset changes. If you have added or removed assets, you will need to create a new release.''',
+      );
+      contentDiffs = FileSetDiff.empty();
+    }
 
     logger.detail('aab content differences: $contentDiffs');
 

packages/shorebird_cli/test/src/archive_analysis/aab_differ_test.dart

@@ -1,5 +1,6 @@
 import 'package:path/path.dart' as p;
 import 'package:shorebird_cli/src/archive_analysis/archive_analysis.dart';
+import 'package:shorebird_cli/src/archive_analysis/archive_differ.dart';
 import 'package:test/test.dart';
 
 void main() {
@@ -13,6 +14,7 @@ void main() {
         p.join(aabFixturesBasePath, 'changed_kotlin.aab');
     final changedDartAndAssetAabPath =
         p.join(aabFixturesBasePath, 'changed_dart_and_asset.aab');
+    final noManifestAabPath = p.join(aabFixturesBasePath, 'no_manifest.aab');
 
     late AabDiffer differ;
 
@@ -38,6 +40,13 @@ void main() {
       });
     });
 
+    test('does not crash if MANIFEST.MF is missing', () {
+      expect(
+        () => differ.changedFiles(baseAabPath, noManifestAabPath),
+        throwsA(isA<DiffFailedException>()),
+      );
+    });
+
     group('contentDifferences', () {
       test('detects no differences between the same aab', () {
         expect(differ.changedFiles(baseAabPath, baseAabPath), isEmpty);

packages/shorebird_cli/test/src/commands/patch/patch_android_command_test.dart

@@ -8,6 +8,7 @@ import 'package:path/path.dart' as p;
 import 'package:platform/platform.dart';
 import 'package:scoped/scoped.dart';
 import 'package:shorebird_cli/src/archive_analysis/archive_analysis.dart';
+import 'package:shorebird_cli/src/archive_analysis/archive_differ.dart';
 import 'package:shorebird_cli/src/auth/auth.dart';
 import 'package:shorebird_cli/src/bundletool.dart';
 import 'package:shorebird_cli/src/cache.dart' show Cache, cacheRef;
@@ -622,6 +623,27 @@ https://github.com/shorebirdtech/shorebird/issues/472
       expect(exitCode, ExitCode.software.code);
     });
 
+    test(
+      'prints warning if differ cannot determine patch differences',
+      () async {
+        when(() => aabDiffer.changedFiles(any(), any()))
+            .thenThrow(DiffFailedException());
+        final tempDir = setUpTempDir();
+        setUpTempArtifacts(tempDir);
+        final exitCode = await IOOverrides.runZoned(
+          () => runWithOverrides(command.run),
+          getCurrentDirectory: () => tempDir,
+        );
+
+        expect(exitCode, ExitCode.success.code);
+        verify(
+          () => logger.warn(
+            '''Could not determine whether patch contains asset changes. If you have added or removed assets, you will need to create a new release.''',
+          ),
+        ).called(1);
+      },
+    );
+
     test('prompts user to continue when Java/Kotlin code changes are detected',
         () async {
       when(() => aabDiffer.containsPotentiallyBreakingNativeDiffs(any()))