[web] [DDC] TypeError: Cannot read properties of undefined (reading 'new')

[AlexV525]

This tracker is for issues related to:

• Dart native and web compilers
• Dart VM

Upstream: cfug/dio#2282

We've split our Dio adapter with conditional imports. However, writing the caller in a specific way does not reference the correct constructor as I can tell.

Consider the example, running this on Flutter Web environment will unexpectedly throw TypeError: Cannot read properties of undefined (reading 'new'):

main.dart

import 'package:dio/dio.dart';
import 'package:flutter/material.dart';

import 'adapter.dart';

void main() {
  try {
    final adapter = makeHttpClientAdapter();
    print(adapter);
  } on Object catch (error) {
    print(error);
  }

  runApp(const MyApp());
}

adapter.dart

import 'package:dio/dio.dart';

import 'client_adapter_io.dart'
    if (dart.library.js_interop) 'client_adapter_web.dart' as adapter;

HttpClientAdapter makeHttpClientAdapter() => adapter.makeHttpClientAdapter();

adapter_io.dart

import 'package:dio/dio.dart';
import 'package:dio/io.dart';

HttpClientAdapter makeHttpClientAdapter() {
  return IOHttpClientAdapter();
}

adapter_web.dart

import 'package:dio/browser.dart';
import 'package:dio/dio.dart';

HttpClientAdapter makeHttpClientAdapter() {
  return BrowserHttpClientAdapter()..withCredentials = true;
}

Workaround

HttpClientAdapter makeHttpClientAdapter() {
  final adapter = HttpClientAdapter() as BrowserHttpClientAdapter;
  adapter.withCredentials = true;
  return adapter;
}

[dart-github-bot]

Summary: The issue is a TypeError thrown when using conditional imports with Dio on Flutter Web. The error occurs because the correct constructor for the HttpClientAdapter is not being referenced due to the way the caller is written.

[AlexV525]

@Rexios80 Do you have any clues what is going on here? 🤔

[Rexios80]

What dart/flutter version? There might be some fixes that still aren't merged into stable.

[Dan-Crane]

@Rexios80 im faced this:

[✓] Flutter (Channel stable, 3.22.2, on macOS 14.5 23F79 darwin-arm64, locale en-RU)
[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.1)
[✓] Xcode - develop for iOS and macOS (Xcode 15.4)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2023.2)
[✓] VS Code (version 1.92.2)
[✓] Connected device (5 available)
[✓] Network resources

[Rexios80]

Can you reproduce on flutter master?

[Dan-Crane]

This also happens on master 3.24.0-1.0.pre.606

[Rexios80]

Is it the cascade that's causing the issue?

[AlexV525]

Is it the cascade that's causing the issue?

Nope. Removing it doesn't help.

[Rexios80]

You say this is a workaround:

HttpClientAdapter makeHttpClientAdapter() {
  final adapter = HttpClientAdapter() as BrowserHttpClientAdapter;
  adapter.withCredentials = true;
  return adapter;
}

What about this fixes the issue if it's not removing the cascade? Is it the cast?

[AlexV525]

You say this is a workaround:

HttpClientAdapter makeHttpClientAdapter() {
  final adapter = HttpClientAdapter() as BrowserHttpClientAdapter;
  adapter.withCredentials = true;
  return adapter;
}

What about this fixes the issue if it's not removing the cascade? Is it the cast?

Yes, creating the adapter like this and force cast it does work, it's not about the cascade. The workaround is to help people to achieve their goal.

[nshahan]

Which of the web environments are you experiencing this issue?

• Production JavaScript (dart2js compiler)
• Production WASM (dart2wasm compiler)
• Development (DDC compiler)

[AlexV525]

Which of the web environments are you experiencing this issue?

• Development (DDC compiler)

The DDC compiler. The built Web application does not run into the issue.

[sigmundch]

@nshahan - I recall we've seen an error with this message before long ago, but we didn't have a repro at hand. Maybe they are related? (see #50380)

[Rexios80]

I actually have this error in one of my projects now. Not sure how it took me this long to notice. The workaround provided by @AlexV525 does fix the issue.

[AlexV525]

This is getting worse according to cfug/dio#2282 (comment)

@nshahan @sigmundch Would you mind taking further investigations?