Set deep linking flag to true by default

[hangyujin]

doc: flutter.dev/go/deep-link-flag-migration

Action item: make sure customers are aware of this change before merging this PR.

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide and the C++, Objective-C, Java style guides.
• I listed at least one issue that this PR fixes in the description above.
• I added new tests to check the change I am making or feature I am adding, or the PR is test-exempt. See testing the engine for instructions on writing and running engine tests.
• I updated/added relevant documentation (doc comments with ///).
• I signed the CLA.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[jmagman]

Is there any mechanism for the framework to say whether pushRouteInformation successfully pushed a known route? If so, it might be better to return that (the non-deprecated version of this API is async https://developer.apple.com/documentation/uikit/uiapplication/1648685-openurl, so we could migrate onto that)

[hangyujin]

@jmagman yes, framework method Future<bool> didPushRouteInformation(RouteInformation routeInformation) does return true when successfully pushed a known route.

But i think migrating to a non-deprecated async API will be a separated issue and a separated PR from this flag change .

[jmagman]

But i think migrating to a non-deprecated async API will be a separated issue and a separated PR from this flag change .

I'm not really concerned that it's deprecated, more that this PR changes behavior where this method will be returning true even when there's no deep linking set up, and it's not opted into.

[hangyujin]

Looks like the framework currently sends routeInformationUpdated message to navigationChannel when route changes. But these navigation messages are only handled on the web, it’s not handled on the iOS engine.

Maybe we can do

1. On the iOS engine, add a method call handler to ios navigationChannel and save the route information so the engine knows if the route is changed.

2. On the iOS engine openURL method, after sending pushRouteInformation, wait for 1 second(just an eye-balled value) and check if the route information is changed, if so, return YES, if not, return NO.

[chunhtai]

Looks like the framework currently sends routeInformationUpdated message to navigationChannel when route changes. But these navigation messages are only handled on the web, it’s not handled on the iOS engine.

Maybe we can do

1. On the iOS engine, add a method call handler to ios navigationChannel and save the route information so the engine knows if the route is changed.
2. On the iOS engine openURL method, after sending pushRouteInformation, wait for 1 second(just an eye-balled value) and check if the route information is changed, if so, return YES, if not, return NO.

Why does iOS need to listen for routeInformationUpdated ? should we be able to tell from didPushRouteInformation's return value to tell whether anything has handled the deeplink?

[hangyujin]

cause didPushRouteInformation's return value is on the framework side, i thought the way for engine to get it is through a method channel, so the ios openURL returns true only when the route is changed on the framework side

[chunhtai]

Can you make _handleNavigationInvocation to return a future of boolean to indicate whether any of the widgetbindObserver.didpushRouteInformation has handled the route or not?

The didUpdateRouteInformation is to report current route in framework to engine. It will be smart enough to check whether the current route/state with the one in engine is the same or not before sending the request. So it is not guaranteed that didUpdateRouteInformation will be called after a successful deeplink

[chunhtai]

That being said we should probably add the feature to reject deeplink in go_router, right now it just swallow all and handle error on the framework side

[hangyujin]

Can you make _handleNavigationInvocation to return a future of boolean to indicate whether any of the widgetbindObserver.didpushRouteInformation has handled the route or not? >> noted, I will do that, thanks!

[reidbaker]

@hangyujin Are you wanting to make more changes or is this ready for revew?

[hangyujin]

@reidbaker i want to land flutter/flutter#147901 and #52643 first.