check if libimobiledevice executables exist (#43767)

packages/flutter_tools/lib/src/cache.dart

@@ -1103,6 +1103,17 @@ class IosUsbArtifacts extends CachedArtifact {
     'libzip',
   ];
 
+  // For unknown reasons, users are getting into bad states where libimobiledevice is
+  // downloaded but some executables are missing from the zip. The names here are
+  // used for additional download checks below, so we can redownload if they are
+  // missing.
+  static const Map<String, List<String>> _kExecutables = <String, List<String>>{
+    'libimobiledevice': <String>[
+      'idevice_id',
+      'ideviceinfo',
+    ],
+  };
+
   @override
   Map<String, String> get environment {
     return <String, String>{
@@ -1110,11 +1121,28 @@ class IosUsbArtifacts extends CachedArtifact {
     };
   }
 
+  @override
+  bool isUpToDateInner() {
+    final List<String> executables =_kExecutables[name];
+    if (executables == null) {
+      return true;
+    }
+    for (String executable in executables) {
+      if (!location.childFile(executable).existsSync()) {
+        return false;
+      }
+    }
+    return true;
+  }
+
   @override
   Future<void> updateInner() {
     if (!platform.isMacOS && !cache.includeAllPlatforms) {
       return Future<void>.value();
     }
+    if (location.existsSync()) {
+      location.deleteSync(recursive: true);
+    }
     return _downloadZipArchive('Downloading $name...', archiveUri, location);
   }
 

packages/flutter_tools/test/general.shard/cache_test.dart

@@ -330,13 +330,45 @@ void main() {
     });
   });
 
-  group('Unsigned mac artifacts', () {
+  group('macOS artifacts', () {
     MockCache mockCache;
 
     setUp(() {
       mockCache = MockCache();
     });
 
+    testUsingContext('verifies executables for libimobiledevice in isUpToDateInner', () async {
+      final IosUsbArtifacts iosUsbArtifacts = IosUsbArtifacts('libimobiledevice', mockCache);
+      when(mockCache.getArtifactDirectory(any)).thenReturn(fs.currentDirectory);
+      iosUsbArtifacts.location.createSync();
+      final File ideviceIdFile = iosUsbArtifacts.location.childFile('idevice_id')
+        ..createSync();
+      iosUsbArtifacts.location.childFile('ideviceinfo')
+        ..createSync();
+
+      expect(iosUsbArtifacts.isUpToDateInner(), true);
+
+      ideviceIdFile.deleteSync();
+
+      expect(iosUsbArtifacts.isUpToDateInner(), false);
+    }, overrides: <Type, Generator>{
+      Cache: () => mockCache,
+      FileSystem: () => MemoryFileSystem(),
+      ProcessManager: () => FakeProcessManager.any(),
+    });
+
+    testUsingContext('Does not verify executables for openssl in isUpToDateInner', () async {
+      final IosUsbArtifacts iosUsbArtifacts = IosUsbArtifacts('openssl', mockCache);
+      when(mockCache.getArtifactDirectory(any)).thenReturn(fs.currentDirectory);
+      iosUsbArtifacts.location.createSync();
+
+      expect(iosUsbArtifacts.isUpToDateInner(), true);
+    }, overrides: <Type, Generator>{
+      Cache: () => mockCache,
+      FileSystem: () => MemoryFileSystem(),
+      ProcessManager: () => FakeProcessManager.any(),
+    });
+
     testUsingContext('use unsigned when specified', () async {
       when(mockCache.useUnsignedMacBinaries).thenReturn(true);