From b54bb6abbb5900ce7d39f2e6b67bbd496772fab6 Mon Sep 17 00:00:00 2001
From: Jonah Williams <jonahwilliams@google.com>
Date: Fri, 22 Nov 2019 14:06:05 -0800
Subject: [PATCH] Dont crash if the tool cannot delete asset directory during
 debugging (#45407)

---
 packages/flutter_tools/lib/src/bundle.dart     | 12 +++++++++++-
 .../test/general.shard/asset_bundle_test.dart  | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/packages/flutter_tools/lib/src/bundle.dart b/packages/flutter_tools/lib/src/bundle.dart
index 8d157ea97f9..e86469d49d1 100644
--- a/packages/flutter_tools/lib/src/bundle.dart
+++ b/packages/flutter_tools/lib/src/bundle.dart
@@ -10,6 +10,7 @@ import 'package:pool/pool.dart';
 import 'asset.dart';
 import 'base/common.dart';
 import 'base/file_system.dart';
+import 'base/logger.dart';
 import 'build_info.dart';
 import 'build_system/build_system.dart';
 import 'build_system/depfile.dart';
@@ -173,9 +174,18 @@ Future<AssetBundle> buildAssets({
 Future<void> writeBundle(
   Directory bundleDir,
   Map<String, DevFSContent> assetEntries,
+  { Logger loggerOverride }
 ) async {
+  loggerOverride ??= logger;
   if (bundleDir.existsSync()) {
-    bundleDir.deleteSync(recursive: true);
+    try {
+      bundleDir.deleteSync(recursive: true);
+    } on FileSystemException catch (err) {
+      loggerOverride.printError(
+        'Failed to clean up asset directory ${bundleDir.path}: $err\n'
+        'To clean build artifacts, use the command "flutter clean".'
+      );
+    }
   }
   bundleDir.createSync(recursive: true);
 
diff --git a/packages/flutter_tools/test/general.shard/asset_bundle_test.dart b/packages/flutter_tools/test/general.shard/asset_bundle_test.dart
index c46baba62a2..1bbb35a38fc 100644
--- a/packages/flutter_tools/test/general.shard/asset_bundle_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_test.dart
@@ -9,8 +9,12 @@ import 'package:file/memory.dart';
 
 import 'package:flutter_tools/src/asset.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/platform.dart';
+import 'package:flutter_tools/src/bundle.dart';
 import 'package:flutter_tools/src/cache.dart';
+import 'package:flutter_tools/src/devfs.dart';
+import 'package:mockito/mockito.dart';
 
 import '../src/common.dart';
 import '../src/context.dart';
@@ -179,4 +183,18 @@ flutter:
     });
   });
 
+  test('Failed directory delete shows message', () async {
+    final MockDirectory mockDirectory = MockDirectory();
+    final BufferLogger bufferLogger = BufferLogger();
+    when(mockDirectory.existsSync()).thenReturn(true);
+    when(mockDirectory.deleteSync(recursive: true)).thenThrow(const FileSystemException('ABCD'));
+
+    await writeBundle(mockDirectory, <String, DevFSContent>{}, loggerOverride: bufferLogger);
+
+    verify(mockDirectory.createSync(recursive: true)).called(1);
+    expect(bufferLogger.errorText, contains('ABCD'));
+  });
 }
+
+class MockDirectory extends Mock implements Directory {}
+