[libcxx-commits] [PATCH] D120996: [libc++] Remove extension to support allocator<const T>

[Louis Dionne via Phabricator via libcxx-commits]

ldionne added a subscriber: EricWF.
ldionne added a comment.

In D120996#3370437 <https://reviews.llvm.org/D120996#3370437>, @rnk wrote:

> In D120996#3362137 <https://reviews.llvm.org/D120996#3362137>, @Quuxplusone wrote:
>
>> This is the sort of thing to alert libc++-vendors about, right?
>
> It seems this change is already causing problems for us. Google aims to uptake new versions of libc++ often. To support that, we are constantly testing new LLVM and libc++ versions ~daily. With this change, we can't continue testing new LLVM and libc++ versions. I estimate that it could take us a week to migrate our code, but that's a pretty soft estimate, I am not a domain expert. I would like to avoid a week long gap in our testing. Would you consider delaying this, setting up an opt-out configuration macro, or some other mitigation strategy to allow vendors to handle this transition gracefully?

Yes. I've been in touch with @EricWF about this. I did not expect this to cause so much trouble. I think we definitely want to make this change in the mid/long term, however we should also make breaking changes in a friendly way whenever possible. I will revert this for now and I'll propose a softer approach (probably with a escape hatch) soon.


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https://reviews.llvm.org/D120996