IssueTracker

Hello!

Similarly to the @ChecksSdkIntAtLeast annotation that was added to androidx.annotation in version 1.2.0-alpha01, it'd be very nice for both app and library developers to have a @ChecksPermissionGranted annotation.

Minimal specification draft

That annotation would be available to use on functions/methods and classes (including abstract classes, which would make subclasses inherit the tooling behavior provided by the annotation).

It would take one of these two parameters:

1. permissionNames, an array of Strings (useful for apps)
2. permissionsParameter, a String which would reference a parameter for the function (or constructor?) where the permission names would arrive as an argument. (useful for libraries) Allowed types of the parameter would be String and its vararg variant (aka. String...). For that case, the tooling would warn at call site if the @ChecksPermissionGranted annotation is not propagated with the same value, unless compile time constants are passed to the referenced parameter, allowing to make the missing permission error suppression work.

Use case

With coroutines, it's possible to make a function that will suspend until a given permission is granted, and it's also possible, with a reference to a FragmentActivity or a Fragment, to ask this permission and await for the user to grant or deny it.

With this library, that's what I'm doing in this example as well as production code thanks to these handy extensions using AlertDialog.

The only bummer is that the IDE tells me that I'm not handling the case where the permission would be denied, which is false. To avoid starting to ignore errors and warnings, I have to put @Suppress("MissingPermission") all over the place, but this is the "nuclear" option, which will not let me spot an extra permission that I'd have forgotten to ensure that I have.

Here's an example: I put the warning suppression because I ensured I have the camera permission, then I need the microphone permission, so I use it, and I'm not warned because @Suppress("MissingPermission") suppresses all runtime permission warnings in the scope. Later on, the app crashes because the permission is not granted there in the app.