Process.argv doesn't have a reified type

[nex3]

The Process.argv getter declares a reified type of List<String>, but because the array in question comes from JS, it doesn't have a reified String type argument. This causes it to throw an error at runtime when passed to pure Dart code that expects a List<String>.

Once dart-lang/sdk#30554 is fixed, it will be possible to modify the argv getter so that it casts the array when accessed from Dart. Until then, it's probably best to make the static type just List so that we get appropriate static errors.

[pulyaevskiy]

I just wrote following test which worked for some reason:

@TestOn('node')
import 'package:node_interop/node_interop.dart';
import 'package:test/test.dart';

void main() {
  group('process', () {
    test('argv', () {
      foo(process.argv);
    });
  });
}

void foo(List<String> args) {
  print(args);
}

Tested on Dart SDK 2.3.0. Am I missing something here?

[nex3]

It looks like dart2js is inlining the call to foo(), which gets rid of the runtime type check. You can tell it not to do that using @noInline:

import 'package:meta/dart2js.dart';
import 'package:node_interop/node_interop.dart';
import 'package:test/test.dart';

void main() {
  group('process', () {
    test('argv', () {
      foo(process.argv);
    });
  });
}

@noInline
void foo(List<String> args) {
  print(args);
}

[pulyaevskiy]

Thanks, good to know! Will give it another round over the weekend.

[alextekartik]

I remember having a similar issue sometime ago on this where I add to reimplement process.argv. Other simple test that shows the issue (without the noInline trick)

test('argv', () {
  expect(process.argv, const TypeMatcher<List<dynamic>>()); // success
  expect(process.argv, const TypeMatcher<List<String>>()); // failure
});

[pulyaevskiy]

I just pushed 1.0.3 with no generic type arguments for Process methods.

There is likely more similar cases in other places, which I'll tackle separately.

Thanks for your help!