tree cf8c77b94dda87584cb0ceaf121341cef8747312
parent 101e526116df778a087a60ace0cad4a0f894bdf4
author twigg <twigg@google.com> 1634765386 -0700
committer Copybara-Service <copybara-worker@google.com> 1634765451 -0700

In CTF.K narrow ToolchainContextKey to execution platform Label. Update docs.

ConfigurationTargetFunction is very sensitive and should only be completed once per-build for a given Label, BuildConfiguration pair due to performance and correctness (considering unsharable action conflicts in cc rules).

Update the documentation of ConfiguredTargetKey to better explain this sensitivity and outline potential pain points.

In theory, using the narrower execution platform Label instead of a ToolchainContextKey reduces the chance that two different ConfigurationTargetKey map to the same (Label, BuildConfiguration) leading to the previously mentioned build issues. Thus, concern 3 in the ConfiguredTargetKey is even less likely. In practice, we do not think this issue has actually been observed in a real build.

PiperOrigin-RevId: 404639477