pkg/vm_service/test/wildcard_test.dart

// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

// SharedOptions=--enable-experiment=wildcard-variables

// ignore: invalid_language_version_override
// @dart = 3.7

import 'dart:developer';
// Tests wildcard import prefixes.
// ignore: unused_import, library_prefixes, no_leading_underscores_for_library_prefixes
import 'dart:io' as _;

import 'package:test/test.dart';
import 'package:vm_service/vm_service.dart';

import 'common/service_test_common.dart';
import 'common/test_helper.dart';

void test() {
  // We define an anonymous function instead of a named one because wildcard
  // parameters can be optimized out of named functions by the compiler, so
  // defining a named function would prevent this test from exercising the
  // wildcard filtering logic in the VM Service's [Frame] building code.
  // ignore: prefer_function_declarations_over_variables
  final foo = <_>(i, _, _) {
    final int _ = 42;
    debugger();
  };

  foo<String>(0, 1, 2);
}

final tests = <IsolateTest>[
  hasStoppedAtBreakpoint,
  (VmService service, IsolateRef isolateRef) async {
    final isolateId = isolateRef.id!;
    final isolate = await service.getIsolate(isolateId);

    final lib =
        await service.getObject(isolateId, isolate.rootLib!.id!) as Library;
    final ioImport =
        lib.dependencies!.firstWhere((e) => e.target!.name == 'dart.io');
    // Wildcard prefixes shouldn't be stripped from imports.
    expect(ioImport.prefix, '_');

    final stack = await service.getStack(isolateId);
    final frame = stack.frames!.first;
    final function =
        await service.getObject(isolateId, frame.function!.id!) as Func;
    expect(function.name, '<anonymous closure>');

    // Type parameter names are replaced with synthetic names in general so we
    // don't need to check for the name '_' here.
    final typeParameters = function.signature!.typeParameters!;
    expect(typeParameters.length, 1);

    // There should only be bound variables for non-wildcard parameters.
    final vars = frame.vars!;
    expect(vars.length, 1);
    expect(vars.first.name, 'i');
  },
];

void main([args = const <String>[]]) => runIsolateTests(
      args,
      tests,
      'wildcard_test.dart',
      testeeConcurrent: test,
      experiments: ['wildcard-variables'],
    );