Resolve Go and C++ toolchains for each Go target#4439
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@dzbarsky @jesses-canva @anguslees FYI, this could use some testing :-) |
jayconrod
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Sep 3, 2025
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jayconrod
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If this passes all the tests, then it's probably good. I don't know if there's a way to test that the original problem is fixed (C++ and Go toolchains resolved for different platforms). Probably not without a very contrived, complicated example.
If I remember correctly, when toolchains were introduced, there were no optional toolchains, so an optional dependency on a fake target was the only way to get that. It seems like config_common.toolchain_type(mandatory = False) is the missing piece.
dzbarsky
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Sep 4, 2025
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I don't have access to any complicated go repos at the moment, but this seems reasonable!
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What type of PR is this?
Bug fix
What does this PR do? Why is it needed?
Before this change, rules_go would resolve the C++ toolchain for a fixed helper target and use it in Go targets via a provider. This results in problems for multi-platform builds since the execution platform of the C++ toolchain needs to match that of the Go toolchain, which can only be enforced if both toolchain requirements are declared on the same rule.
Which issues(s) does this PR fix?
Fixes #4127
Work towards #3740 (comment)
Other notes for review