[BUG] Non-backwards-compatible breaking change in Application Launcher cluster.

[bzbarsky-apple]

Reproduction steps

#30134 made a breaking change to client APIs by changing a writable attribute to readonly.

We need to either revert that change or figure out some other way of making the APIs continue to exist.

Bug prevalence

Always

GitHub hash of the SDK that was being used

6ec33d4

Platform

darwin

Platform Version(s)

No response

Anything else?

No response

[bzbarsky-apple]

@andy31415

[andy31415]

What is the breaking change (i.e. what methods are missing as a result)? I had assumed this was not an ABI issue.

If this is just some write* method availability, could we on-off them into some h/mm file?

[andy31415]

I can see no reasonable way to change the spec to make this attribute writable (what would be the meaning? Saying SHALL always return an error also seems wrong) nor do I think keeping it writable in the sdk not in the spec is that practical.

[bzbarsky-apple]

If this is just some write* method availability, could we on-off them into some h/mm file?

That is what it is, and maybe we can, but this is breaking things in the meantime. I am happy to look into doing this change in a non-breaking way, but I can't do it this week.