commit 4aaa6de306f83ce366ab989f8413e29436ab0838
author Daniel Wagner-Hall <dwagnerhall@apple.com> Fri May 19 20:09:52 2023 +0200
committer GitHub <noreply@github.com> Fri May 19 11:09:52 2023 -0700
tree 92d9ee3371205ee19bc98ed0e728151c09124a89
parent f1b19c394f3edffa041b88be1bc371950476d1d2

Allow specifying exec and target compatibility constraints (#1971)

Extra target triples may only be appropriate for specific platforms
(e.g. if you register a toolchain with the exec_triple
`x86_64-unknown-linux-gnu` with an extra target triple of
`x86_64-unknown-linux-musl`, you may want differing
`target_compatible_with` values for each of those two target triples.

This allows for specifying explicit `exec_compatible_with` lists per
toolchain (which was already supported by `rust_toolchain_repository`
just not proxied by `rust_repository_set`), and explicit
`target_compatible_with` lists, both for the default triple and for
extra ones.

I'm not 100% sure on our pre-existing assumption that every toolchain
supports compiling targeting its own exec platform, i.e. the
'`[exec_triple]`' part of https://github.com/bazelbuild/rules_rust/blob/937e63399b111a6d7ee53b187e4d113300b089e9/rust/repositories.bzl#L845
but it _does_ generally hold, and supplying a way of removing that
default assumption is definitely a separate PR for another day if it
becomes relevant to anyone.