It looks like this pull request may not have tests. Please make sure to add tests or get an explicit test exemption before merging.

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.If you believe this PR qualifies for a test exemption, contact "@test-exemption-reviewer" in the #hackers channel in Discord (don't just cc them here, they won't see it!). The test exemption team is a small volunteer group, so all reviewers should feel empowered to ask for tests, without delegating that responsibility entirely to the test exemption group.

Even after #169998 lands, I don't know that we want to do this. #169998 only handles newly created Flutter apps. This PR will show that warning for every pre-existing Flutter app.

Perhaps we can try to auto-migrate people AppDelegates and then after some time we can introduce this warning?

I don't think we should try to migrate users in this case. We have a lot of work to do, trying to handle the infinite ways people could be running into this will be a big investment (x2 for swift and objc). I think Apple has shown us a good way forward, provide a warning with a generous grace period, then pull the plug.

I don't think we should try to migrate users in this case. We have a lot of work to do, trying to handle the infinite ways people could be running into this will be a big investment (x2 for swift and objc). I think Apple has shown us a good way forward, provide a warning with a generous grace period, then pull the plug.

I wasn't thinking we'd try to catch every use case - just the basic use case (if the AppDelegate matches the old template exactly, we can safely change it I think). That would get most users (probably?). Then for users who have done custom things to their AppDelegate, they can migrate manually

If you don't handle every case, wouldn't you still want this warning? Can you file an issue for the mechanism that automatically updates app delegates?

If you don't handle every case, wouldn't you still want this warning? Can you file an issue for the mechanism that automatically updates app delegates?

Good point, we would still want the warning - but only after the migration code had landed. I think we should also add more documentation on how to migrate this specific use case. Currently the docs are mostly about platform channels: https://docs.flutter.dev/release/breaking-changes/uiscenedelegate#creating-platform-channels-in-application-didfinishlaunchingwithoptions

Filed #170167

I think we should also add more documentation on how to migrate this specific use case. Currently the docs are mostly about platform channels: https://docs.flutter.dev/release/breaking-changes/uiscenedelegate#creating-platform-channels-in-application-didfinishlaunchingwithoptions

@vashworth what were you referring to when you said "this specific use case"? Are you talking about specifically calling out the case where they aren't creating platform channels, they are just using he GeneratedPluginRegistrant?

I think we should also add more documentation on how to migrate this specific use case.

Done flutter/website#12111

I'll leave this PR around until the iOS team decides they want to land it.

Is this stale? The linked issue that was marked as a dependency was completed.

Is this stale? The linked issue that was marked as a dependency was completed.

Sorta, the team has decided they don't want to land it until #170167 is completed. But that work has been postponed. I can drop this as a draft or put the diff in the linked issue.

You can just close it. Since it its referenced from that issue, we'll still have a record of it on GitHub.