[libcxx-commits] [PATCH] D116344: [libc++] [ABI BREAK] Conform lognormal_distribution::param_type.

[Arthur O'Dwyer via Phabricator via libcxx-commits]

Quuxplusone added a comment.

@ldionne wrote:

> If it does, we will make this a proper ABI macro and only enable it in the ABI-unstable build.

I agree with everything you said except this sentence. I don't believe we know a realistic path to ever make "ABIv2" the //default//, which means that if we do this patch only in ABIv2, then we're not doing it by default for "new customers" (so to speak). And I think this UB is a big enough deal that it //needs// to be fixed-by-default for new customers. //If// anyone complains about the new `lognormal_distribution` (which I think we both believe is highly unlikely), then I think we would have to investigate some way to keep this patch enabled by default for ABIv1 users, but disabled for those specific vendors who complained — which I think means simply "do exactly this PR, //but// commit to supporting the `_LIBCPP_ABI_OLD_LOGNORMAL_DISTRIBUTION` macro forever."
(TLDR: I do //not// think it should be acceptable to enable `_LIBCPP_ABI_OLD_LOGNORMAL_DISTRIBUTION` by default in ABIv1, even if we get a few complaints. But again, we'll probably get zero complaints and so it'll be moot, which is great.)


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https://reviews.llvm.org/D116344