[SOLVED] Issue with flutter_web_auth_2 - Unresolved reference to Registrar

Hey Appwrite Team! 👋 I'm currently building a Flutter project with Appwrite and IDX, but I've run into an issue with the flutter_web_auth_2 package. The version Appwrite depends on (3.1.2) is causing build errors due to the deprecated Registrar API in Android. I tried upgrading the package, but it seems Appwrite is locked into this version. Is there a specific reason for this? 🤔 Are there plans to update the dependency soon, or is there a recommended workaround? Would really appreciate any guidance! 🙌 Thanks in advance! 🚀

Just fork the flutter sdk and update webauth2 in the meantime and then link your github repo in your projects pubspec.yaml

You could of course make a PR but Appwrite really takes long reviewing PRs

This should take less then 5min of your time.

Thanks, @Joshi ! That’s a solid suggestion. Forking and updating the dependency would definitely be a quick fix.

That said, I’m working on a long-term project, so I want to make sure whatever I do is maintainable. Since I’m also part of the GitHub Appwrite organization, I’m trying to keep things aligned with official updates. I’m also considering other options like upgrading/downgrading Flutter/Dart to see if that helps.

For context, my workspace on IDX:
Flutter: 3.28.0-0.1.pre (beta)
Dart: 3.7.0 (beta)

I’m also moving from React to Flutter for this project, so I want to set things up properly from the start. Do you think Appwrite would consider updating this dependency officially, or should I just fork it for now?

Appreciate the input! 🙌

They will update it for sure. I always advise developer to take matters in their own hand whenever possible. You are hitting a roadblock and you are not able to continue at this point. So you want to waste your precious time or do you want to continue developing?

1. Fork the sdk
2. Change webauth2 to flutter_web_auth_2: ^4.1.0
3. In your project pubspec.yaml file replace Appwrite with this

  git:
    url: https://github.com/<your_github_name>/Appwrite.git
    ref: main```

Okey!:appwritehero:

**Followup: ** I did some searching, and it seems like I might be the only one facing this issue, so I just wanted to confirm if it’s specific to me. It’s a major roadblock, and I don’t want to waste time if others are already dealing with it. I’m trying to figure out whether I should wait for an update or go for a workaround.

Give this a try. It literally takes less then 5min, afterwards you know for a certainty whether that was the cause or not

whats the build error you mentioned?

Error:

2025-01-30T06:34:59Z [android] Error: e: file:///home/user/.pub-cache/hosted/pub.dev/flutter_web_auth_2-3.1.2/android/src/main/kotlin/com/linusu/flutter_web_auth_2/FlutterWebAuth2Plugin.kt:15:48 Unresolved reference: Registrar
2025-01-30T06:34:59Z [android] 
2025-01-30T06:34:59Z [android] Error: e: file:///home/user/.pub-cache/hosted/pub.dev/flutter_web_auth_2-3.1.2/android/src/main/kotlin/com/linusu/flutter_web_auth_2/FlutterWebAuth2Plugin.kt:22:33 Unresolved reference: Registrar

Cause:

The error occurs because the code is referencing Registrar, a class from the old Flutter embedding API, which is no longer supported in Flutter 2.0 and beyond. Specifically, the error is in the file:

file:///home/user/.pub-cache/hosted/pub.dev/flutter_web_auth_2-3.1.2/android/src/main/kotlin/com/linusu/flutter_web_auth_2/FlutterWebAuth2Plugin.kt

The references to Registrar are found on lines 15 and 22 of the FlutterWebAuth2Plugin.kt file. These lines are attempting to use the deprecated Registrar class, which leads to the unresolved reference error in the context of newer versions of Flutter.

Origin:

The issue originates from using flutter_web_auth_2 version 3.1.2, which was not updated to support Flutter 2.0 and higher. This plugin still relies on the legacy Android embedding method (older than Flutter 1.12), which was removed starting from Flutter 1.12. The file in question, FlutterWebAuth2Plugin.kt, was written for the old embedding system, and when compiling with a newer version of Flutter (3.x in my case), it throws the unresolved reference error for Registrar.

Dependencies:

• Flutter version: Likely 3.28.0 (Beta), which uses the new embedding system.
• Plugin: flutter_web_auth_2 version 3.1.2.

@Joshi I will work around for sure! Thanks for support. 😊

let me ping the team and see if we can resolve this via bumping the dependency.

also, @SillyDryCoder does using override help -

dependency_overrides:
  flutter_web_auth_2: 4.x.x

Let’s Try!

I haven’t tried updating yet since I’m still relatively new to Flutter, and I’ve been working around this for the last 2 days. I tried forcing overrides and overwriting dependency statements, but I keep running into conflicts. The issue is that Appwrite is stuck on a specific version:

flutter_web_auth_2: ^3.1.2

The solution Darshan proposed will override the version, no matter what version the underlying packages use.

It is a good solution that will not require a fork

try like this -

dependencies:
  flutter:
    sdk: flutter

  # other depes
  appwrite: ^14.0.0
  cupertino_icons: ^1.0.8

dependency_overrides:
  flutter_web_auth_2: 4.1.0 # <<< this should work.

Great! Working now, Thanks for a good solution @Darshan Pandya . Also warm thanks to @Joshi . ❤️

I’ll follow up if any other issues come up on my end. Until then, goodbye! 🙌 Big thanks to the Appwrite team and the community for all the efforts! Appreciate it!

Good to hear that its solved. Please add prefix to the thread title as [SOLVED] if your issue is resolved.

Happy Appwriting :appwritepeepo:.

[SOLVED] Issue with flutter_web_auth_2 - Unresolved reference to Registrar