flutter

flutter copied to clipboard

Steps to Reproduce

Linked to https://github.com/firebase/flutterfire/issues/9587

In FlutterFire, we are using channels with arbitrary names to listen to events emitted by native. It appears that using a channel that has a Unicode character; the channel will fail with

MissingPluginException (MissingPluginException(No implementation found for method getPlatformVersion on channel hello))

Expected results: We should be able to use Unicode characters in MethodChannels.

Actual results:

MissingPluginException (MissingPluginException(No implementation found for method getPlatformVersion on channel hello))

final methodChannel = const MethodChannel('hello\u{0000}');

channel = MethodChannel(flutterPluginBinding.binaryMessenger, "hello\u0000")

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.3.9, on macOS 13.0 22A380 darwin-arm, locale en-FR)
[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 14.0.1)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2021.3)
[✓] VS Code (version 1.73.1)
[✓] Connected device (3 available)
[✓] HTTP Host Availability

• No issues found!

Dec 07 '22 12:12 Lyokone

In FlutterFire, we are using channels with arbitrary names to listen to events emitted by native.

Can you elaborate on the usecase here? Why do you need to have channels whose names contain arbitrary strings?

It appears that using a channel that has a Unicode character; the channel will fail

Is this true of all unicode characters? You've shown the null byte, which is generally a string terminator.

Dec 07 '22 15:12 stuartmorgan-g

The use case for FlutterFire is to create a method channel per request from the user and close the native listener properly when the subscription is closed. To create the name of those channels, we are using the values the user provides.

I've tried with a couple of other unicode characters and they all work 👍 It seems to be only the u{0000}

Dec 08 '22 08:12 Lyokone

Null has a special meaning as a string terminator in some common representations. This isn't even possible to express without charging the C embedder API for the sole purpose of supporting this one character.

Given the complexity of getting this right across all implementions, and the fact that it seems like an extremely niche use case, I think we should probably just document that this character isn't supported.

Dec 08 '22 11:12 stuartmorgan-g

Thanks for your help. I think we’ll just workaround this.

Dec 08 '22 11:12 Lyokone

Closing this as working as intended.

Dec 12 '22 19:12 chinmaygarde

@chinmaygarde Why is not having this documented WAI? The fact that null bytes aren't going to work isn't obvious in all contexts.

Dec 12 '22 19:12 stuartmorgan-g

I glossed over the last sentence of your last reply where the issue was repurposed as an update to documentation. We closed this in triage as an issue asking to support null bytes in method channel names.

I've updated the title to match the ask and reopened.

Dec 12 '22 19:12 chinmaygarde

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

Jul 26 '23 22:07 github-actions[bot]