[flutter_tools] add --null-assertions flag for debugging with null safety (#63416)

2025-06-03 00:51:18 +00:00 · 2020-08-11 11:36:03 -07:00 · 2020-08-11 11:36:03 -07:00 · c86d090e6f
commit c86d090e6f
parent cbe0999d1f
13 changed files with 54 additions and 9 deletions
--- a/packages/flutter_tools/lib/src/android/android_device.dart
+++ b/packages/flutter_tools/lib/src/android/android_device.dart
@ -626,9 +626,8 @@ class AndroidDevice extends Device {
      );
    }

-    List<String> cmd;
-
-    cmd = <String>[
+    final String dartVmFlags = computeDartVmFlags(debuggingOptions);
+    final List<String> cmd = <String>[
      'shell', 'am', 'start',
      '-a', 'android.intent.action.RUN',
      '-f', '0x20000000', // FLAG_ACTIVITY_SINGLE_TOP
@ -665,8 +664,8 @@ class AndroidDevice extends Device {
          ...<String>['--ez', 'start-paused', 'true'],
        if (debuggingOptions.disableServiceAuthCodes)
          ...<String>['--ez', 'disable-service-auth-codes', 'true'],
-        if (debuggingOptions.dartFlags.isNotEmpty)
-          ...<String>['--es', 'dart-flags', debuggingOptions.dartFlags],
+        if (dartVmFlags.isNotEmpty)
+          ...<String>['--es', 'dart-flags', dartVmFlags],
        if (debuggingOptions.useTestFonts)
          ...<String>['--ez', 'use-test-fonts', 'true'],
        if (debuggingOptions.verboseSystemLogs)
--- a/packages/flutter_tools/lib/src/commands/run.dart
+++ b/packages/flutter_tools/lib/src/commands/run.dart
@ -423,6 +423,7 @@ class RunCommand extends RunCommandBase {
        fastStart: boolArg('fast-start')
          && !runningWithPrebuiltApplication
          && devices.every((Device device) => device.supportsFastStart),
+        nullAssertions: boolArg('null-assertions'),
      );
    }
  }
--- a/packages/flutter_tools/lib/src/commands/test.dart
+++ b/packages/flutter_tools/lib/src/commands/test.dart
@ -265,6 +265,7 @@ class TestCommand extends FlutterCommand {
      web: stringArg('platform') == 'chrome',
      randomSeed: stringArg('test-randomize-ordering-seed'),
      extraFrontEndOptions: getBuildInfo(forcedBuildMode: BuildMode.debug).extraFrontEndOptions,
+      nullAssertions: boolArg(FlutterOptions.kNullAssertions),
    );

    if (collector != null) {
--- a/packages/flutter_tools/lib/src/device.dart
+++ b/packages/flutter_tools/lib/src/device.dart
@ -790,6 +790,7 @@ class DebuggingOptions {
    this.webEnableExpressionEvaluation = false,
    this.vmserviceOutFile,
    this.fastStart = false,
+    this.nullAssertions = false,
   }) : debuggingEnabled = true;

  DebuggingOptions.disabled(this.buildInfo, {
@ -821,7 +822,8 @@ class DebuggingOptions {
      deviceVmServicePort = null,
      vmserviceOutFile = null,
      fastStart = false,
-      webEnableExpressionEvaluation = false;
+      webEnableExpressionEvaluation = false,
+      nullAssertions = false;

  final bool debuggingEnabled;

@ -868,6 +870,8 @@ class DebuggingOptions {
  final String vmserviceOutFile;
  final bool fastStart;

+  final bool nullAssertions;
+
  bool get hasObservatoryPort => hostVmServicePort != null;
 }

@ -993,3 +997,14 @@ class NoOpDevicePortForwarder implements DevicePortForwarder {
  @override
  Future<void> dispose() async { }
 }
+
+/// Append --null_assertions to any existing Dart VM flags if
+/// [debuggingOptions.nullAssertions] is true.
+String computeDartVmFlags(DebuggingOptions debuggingOptions) {
+  return <String>[
+    if (debuggingOptions.dartFlags?.isNotEmpty ?? false)
+      debuggingOptions.dartFlags,
+    if (debuggingOptions.nullAssertions)
+      '--null_assertions',
+  ].join(',');
+}
--- a/packages/flutter_tools/lib/src/ios/devices.dart
+++ b/packages/flutter_tools/lib/src/ios/devices.dart
@ -355,6 +355,7 @@ class IOSDevice extends Device {
      ?? math.Random(packageId.hashCode).nextInt(16383) + 49152;

    // Step 3: Attempt to install the application on the device.
+    final String dartVmFlags = computeDartVmFlags(debuggingOptions);
    final List<String> launchArguments = <String>[
      '--enable-dart-profiling',
      // These arguments are required to support the fallback connection strategy
@ -363,7 +364,7 @@ class IOSDevice extends Device {
      '--disable-service-auth-codes',
      '--observatory-port=$assumedObservatoryPort',
      if (debuggingOptions.startPaused) '--start-paused',
-      if (debuggingOptions.dartFlags.isNotEmpty) '--dart-flags="${debuggingOptions.dartFlags}"',
+      if (dartVmFlags.isNotEmpty) '--dart-flags="$dartVmFlags"',
      if (debuggingOptions.useTestFonts) '--use-test-fonts',
      // "--enable-checked-mode" and "--verify-entry-points" should always be
      // passed when we launch debug build via "ios-deploy". However, we don't
--- a/packages/flutter_tools/lib/src/ios/simulators.dart
+++ b/packages/flutter_tools/lib/src/ios/simulators.dart
@ -411,6 +411,7 @@ class IOSSimulator extends Device {
    }

    // Prepare launch arguments.
+    final String dartVmFlags = computeDartVmFlags(debuggingOptions);
    final List<String> args = <String>[
      '--enable-dart-profiling',
      if (debuggingOptions.debuggingEnabled) ...<String>[
@ -423,6 +424,7 @@ class IOSSimulator extends Device {
        if (debuggingOptions.skiaDeterministicRendering) '--skia-deterministic-rendering',
        if (debuggingOptions.useTestFonts) '--use-test-fonts',
        if (debuggingOptions.traceAllowlist != null) '--trace-allowlist="${debuggingOptions.traceAllowlist}"',
+        if (dartVmFlags.isNotEmpty) '--dart-flags=$dartVmFlags'
        '--observatory-port=${debuggingOptions.hostVmServicePort ?? 0}',
      ],
    ];
--- a/packages/flutter_tools/lib/src/runner/flutter_command.dart
+++ b/packages/flutter_tools/lib/src/runner/flutter_command.dart
@ -113,6 +113,7 @@ class FlutterOptions {
  static const String kNullSafety = 'sound-null-safety';
  static const String kDeviceUser = 'device-user';
  static const String kAnalyzeSize = 'analyze-size';
+  static const String kNullAssertions = 'null-assertions';
 }

 abstract class FlutterCommand extends Command<void> {
@ -500,6 +501,12 @@ abstract class FlutterCommand extends Command<void> {
      defaultsTo: null,
      hide: hide,
    );
+    argParser.addFlag(FlutterOptions.kNullAssertions,
+      help:
+        'Perform additional null assertions on the boundaries of migrated and '
+        'unmigrated code. This setting is not currently supported on desktop '
+        'devices.'
+    );
  }

  void usesExtraFrontendOptions() {
--- a/packages/flutter_tools/lib/src/test/flutter_platform.dart
+++ b/packages/flutter_tools/lib/src/test/flutter_platform.dart
@ -92,6 +92,7 @@ FlutterPlatform installHook({
  List<String> extraFrontEndOptions,
  // Deprecated, use extraFrontEndOptions.
  List<String> dartExperiments,
+  bool nullAssertions = false,
 }) {
  assert(testWrapper != null);
  assert(enableObservatory || (!startPaused && observatoryPort == null));
@ -125,6 +126,7 @@ FlutterPlatform installHook({
    flutterProject: flutterProject,
    icudtlPath: icudtlPath,
    extraFrontEndOptions: extraFrontEndOptions,
+    nullAssertions: nullAssertions,
  );
  platformPluginRegistration(platform);
  return platform;
@ -268,6 +270,7 @@ class FlutterPlatform extends PlatformPlugin {
    this.projectRootDirectory,
    this.flutterProject,
    this.icudtlPath,
+    this.nullAssertions = false,
    @required this.extraFrontEndOptions,
  }) : assert(shellPath != null);

@ -290,6 +293,7 @@ class FlutterPlatform extends PlatformPlugin {
  final FlutterProject flutterProject;
  final String icudtlPath;
  final List<String> extraFrontEndOptions;
+  final bool nullAssertions;

  Directory fontsDirectory;

@ -844,6 +848,8 @@ class FlutterPlatform extends PlatformPlugin {
      '--non-interactive',
      '--use-test-fonts',
      '--packages=$packages',
+      if (nullAssertions)
+        '--dart-flags=--null_assertions',
      testPath,
    ];

--- a/packages/flutter_tools/lib/src/test/runner.dart
+++ b/packages/flutter_tools/lib/src/test/runner.dart
@ -52,6 +52,7 @@ abstract class FlutterTestRunner {
    bool web = false,
    String randomSeed,
    @required List<String> extraFrontEndOptions,
+    bool nullAssertions = false,
  });
 }

@ -86,6 +87,7 @@ class _FlutterTestRunnerImpl implements FlutterTestRunner {
    bool web = false,
    String randomSeed,
    @required List<String> extraFrontEndOptions,
+    bool nullAssertions = false,
  }) async {
    // Configure package:test to use the Flutter engine for child processes.
    final String shellPath = globals.artifacts.getArtifactPath(Artifact.flutterTester);
@ -178,6 +180,7 @@ class _FlutterTestRunnerImpl implements FlutterTestRunner {
      flutterProject: flutterProject,
      icudtlPath: icudtlPath,
      extraFrontEndOptions: extraFrontEndOptions,
+      nullAssertions: nullAssertions,
    );

    // Make the global packages path absolute.
--- a/packages/flutter_tools/test/commands.shard/hermetic/test_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/test_test.dart
@ -185,6 +185,7 @@ class FakeFlutterTestRunner implements FlutterTestRunner {
    bool web = false,
    String randomSeed,
    @override List<String> extraFrontEndOptions,
+    bool nullAssertions = false,
  }) async {
    lastEnableObservatoryValue = enableObservatory;
    return exitCode;
--- a/packages/flutter_tools/test/general.shard/android/android_device_start_test.dart
+++ b/packages/flutter_tools/test/general.shard/android/android_device_start_test.dart
@ -254,7 +254,7 @@ void main() {
        '--ez', 'verify-entry-points', 'true',
        '--ez', 'start-paused', 'true',
        '--ez', 'disable-service-auth-codes', 'true',
-        '--es', 'dart-flags', 'foo',
+        '--es', 'dart-flags', 'foo,--null_assertions',
        '--ez', 'use-test-fonts', 'true',
        '--ez', 'verbose-logging', 'true',
        '--user', '10',
@ -281,6 +281,7 @@ void main() {
        purgePersistentCache: true,
        useTestFonts: true,
        verboseSystemLogs: true,
+        nullAssertions: true,
      ),
      platformArgs: <String, dynamic>{},
      userIdentifier: '10',
--- a/packages/flutter_tools/test/general.shard/device_test.dart
+++ b/packages/flutter_tools/test/general.shard/device_test.dart
@ -416,6 +416,13 @@ void main() {
      );
    });
  });
+
+  testWithoutContext('computeDartVmFlags handles various combinations of Dart VM flags and null_assertions', () {
+    expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, dartFlags: null)), '');
+    expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, dartFlags: '--foo')), '--foo');
+    expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, dartFlags: '', nullAssertions: true)), '--null_assertions');
+    expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, dartFlags: '--foo', nullAssertions: true)), '--foo,--null_assertions');
+  });
 }

 class TestDeviceManager extends DeviceManager {
--- a/packages/flutter_tools/test/general.shard/ios/ios_device_start_prebuilt_test.dart
+++ b/packages/flutter_tools/test/general.shard/ios/ios_device_start_prebuilt_test.dart
@ -319,7 +319,7 @@ void main() {
            '--disable-service-auth-codes',
            '--observatory-port=60700',
            '--start-paused',
-            '--dart-flags="--foo"',
+            '--dart-flags="--foo,--null_assertions"',
            '--enable-checked-mode',
            '--verify-entry-points',
            '--enable-software-rendering',
@ -385,6 +385,7 @@ void main() {
        cacheSkSL: true,
        purgePersistentCache: true,
        verboseSystemLogs: true,
+        nullAssertions: true,
      ),
      platformArgs: <String, dynamic>{},
      fallbackPollingDelay: Duration.zero,