Hashmap changes causing rust binary non-reproducible

[sundeep-kokkonda]

Hello,

The changes referred below are adding the rust generated objects with a unique hash extension (as I understood, this to avoid overwriting the objects with same name).
https://github.com/rust-lang/cc-rs/blob/e5bbdfa1fa468c028cb38fee6c35a3cf2e5a2736/src/lib.rs#L1040C1-L1057C15

But this change making the rust binaries are non-reproducible. The rust libs/binaries containing objects names in it and those are differed between the builds with a different hash-id. Currently as a workaround, we reverted the respective changes and that fixed the problem for us.

[NobodyXu]

Hmm maybe we could use something that is more stable for the hashing.

BTW if you need to use the object files generated, then maybe you can use cc::Build::compile_intermediates?

[mati865]

I doubt that code is the problem, current implementation of DefaultHasher is reproducible: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=a9c791e10dcddcc0a72c6a17d1b66ea1

HashMap is not because it purposely randomizes seed, but I don't see it there.