InheritedElement.removeDependent()

[s0nerik]

Call the dependency.removeDependent(this) instead of dependency._dependents.remove(this) inside the Element.deactivate(). This allows InheritedElements to know when they can release resources associated with a given dependent Element.

Fixes #129207

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[s0nerik]

@goderbauer I've added the test. Please take a look.

[goderbauer]

There's a lengthy discussion about exactly this API in #128432, which hasn't reached a conclusion yet and we should hold off on this change until it does. I would encourage you to post your use case there as that seems to be what's still missing: a compelling argument for actually having this API.

[s0nerik]

I already have a slightly adjusted version of this PR that actually solves #128432. @goderbauer please let me know if I should create a new PR for that or just push these changes into this one and adjust the description a bit.

[goderbauer]

@s0nerik I lost track of this PR and I apologize for the delay. If we actually decide to do this, I would prefer the approach that was outlined in the first few comments of #128432 (i.e. introduce a removeDependency method to complete the existing set of update, get, set methods) instead of adding a separate notification mechanism as implemented in this PR. Is that the change you had in mind with your previous comment? Would you mind pushing that into this PR so we can evaluate that?

[s0nerik]

Hey @goderbauer, thanks for reaching out. I've pushed the changes I mentioned before along with some doc comment adjustments for clarity.

BTW, I named the method removeDependent, not removeDependency since it makes much more sense to me that way as it is defined on an InheritedElement and is supposed to remove another Element from the list of dependents of this InheritedElement.

[goderbauer]

LGTM after doc nit is resolved.

[goderbauer]

@s0nerik Can you rebase this with the latest master to make the checks happy?

[s0nerik]

@goderbauer All checks seem to be happy now.

[goderbauer]

LGTM