catch errors during gradle update (#37526)

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

@@ -12,6 +12,7 @@ import '../artifacts.dart';
 import '../base/common.dart';
 import '../base/context.dart';
 import '../base/file_system.dart';
+import '../base/io.dart';
 import '../base/logger.dart';
 import '../base/os.dart';
 import '../base/platform.dart';
@@ -310,7 +311,16 @@ Future<String> _initializeGradle(FlutterProject project) async {
   printTrace('Using gradle from $gradle.');
   // Validates the Gradle executable by asking for its version.
   // Makes Gradle Wrapper download and install Gradle distribution, if needed.
-  await runCheckedAsync(<String>[gradle, '-v'], environment: _gradleEnv);
+  try {
+    await runCheckedAsync(<String>[gradle, '-v'], environment: _gradleEnv);
+  } catch (e) {
+    if (e is ProcessException &&
+        e.toString().contains('java.io.FileNotFoundException: https://downloads.gradle.org') ||
+        e.toString().contains('java.io.IOException: Unable to tunnel through proxy')) {
+      throwToolExit('$gradle threw an error while trying to update itself.\n$e');
+    }
+    rethrow;
+  }
   status.stop();
   return gradle;
 }

packages/flutter_tools/test/general.shard/android/gradle_test.dart

@@ -14,6 +14,7 @@ import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/common.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/os.dart';
+import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/ios/xcodeproj.dart';
@@ -849,6 +850,109 @@ flutter:
     });
   });
 
+  group('Gradle HTTP failures', () {
+    MemoryFileSystem fs;
+    Directory tempDir;
+    Directory gradleWrapperDirectory;
+    MockProcessManager mockProcessManager;
+    String gradleBinary;
+
+    setUp(() {
+      fs = MemoryFileSystem();
+      tempDir = fs.systemTempDirectory.createTempSync('artifacts_test.');
+      gradleBinary = platform.isWindows ? 'gradlew.bat' : 'gradlew';
+      gradleWrapperDirectory = fs.directory(
+        fs.path.join(tempDir.path, 'bin', 'cache', 'artifacts', 'gradle_wrapper'));
+      gradleWrapperDirectory.createSync(recursive: true);
+      gradleWrapperDirectory
+        .childFile(gradleBinary)
+        .writeAsStringSync('irrelevant');
+      gradleWrapperDirectory
+        .childDirectory('gradle')
+        .childDirectory('wrapper')
+        .createSync(recursive: true);
+      gradleWrapperDirectory
+        .childDirectory('gradle')
+        .childDirectory('wrapper')
+        .childFile('gradle-wrapper.jar')
+        .writeAsStringSync('irrelevant');
+
+      mockProcessManager = MockProcessManager();
+    });
+
+    testUsingContext('throws toolExit if gradle fails while downloading', () async {
+      final List<String> cmd = <String>[
+        fs.path.join(fs.currentDirectory.path, 'android', gradleBinary),
+        '-v',
+      ];
+      const String errorMessage = '''
+Exception in thread "main" java.io.FileNotFoundException: https://downloads.gradle.org/distributions/gradle-4.1.1-all.zip
+at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1872)
+at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
+at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254)
+at org.gradle.wrapper.Download.downloadInternal(Download.java:58)
+at org.gradle.wrapper.Download.download(Download.java:44)
+at org.gradle.wrapper.Install\$1.call(Install.java:61)
+at org.gradle.wrapper.Install\$1.call(Install.java:48)
+at org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
+at org.gradle.wrapper.Install.createDist(Install.java:48)
+at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:128)
+at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)''';
+      final ProcessException exception = ProcessException(
+        gradleBinary,
+        <String>['-v'],
+        errorMessage,
+        1,
+      );
+      when(mockProcessManager.run(cmd, workingDirectory: anyNamed('workingDirectory'), environment: anyNamed('environment')))
+        .thenThrow(exception);
+      await expectLater(() async {
+        await checkGradleDependencies();
+      }, throwsToolExit(message: errorMessage));
+    }, overrides: <Type, Generator>{
+      Cache: () => Cache(rootOverride: tempDir),
+      FileSystem: () => fs,
+      ProcessManager: () => mockProcessManager,
+    });
+
+    testUsingContext('throw toolExit if gradle fails downloading with proxy error', () async {
+      final List<String> cmd = <String>[
+        fs.path.join(fs.currentDirectory.path, 'android', gradleBinary),
+        '-v',
+      ];
+      const String errorMessage = '''
+Exception in thread "main" java.io.IOException: Unable to tunnel through proxy. Proxy returns "HTTP/1.1 400 Bad Request"
+at sun.net.www.protocol.http.HttpURLConnection.doTunneling(HttpURLConnection.java:2124)
+at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:183)
+at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1546)
+at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
+at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254)
+at org.gradle.wrapper.Download.downloadInternal(Download.java:58)
+at org.gradle.wrapper.Download.download(Download.java:44)
+at org.gradle.wrapper.Install\$1.call(Install.java:61)
+at org.gradle.wrapper.Install\$1.call(Install.java:48)
+at org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
+at org.gradle.wrapper.Install.createDist(Install.java:48)
+at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:128)
+at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)''';
+      final ProcessException exception = ProcessException(
+        gradleBinary,
+        <String>['-v'],
+        errorMessage,
+        1,
+      );
+      when(mockProcessManager.run(cmd, environment: anyNamed('environment'), workingDirectory: null))
+        .thenThrow(exception);
+      await expectLater(() async {
+        await checkGradleDependencies();
+      }, throwsToolExit(message: errorMessage));
+    }, overrides: <Type, Generator>{
+      Cache: () => Cache(rootOverride: tempDir),
+      FileSystem: () => fs,
+      ProcessManager: () => mockProcessManager,
+    });
+  });
+
   group('injectGradleWrapperIfNeeded', () {
     MemoryFileSystem memoryFileSystem;
     Directory tempDir;