Rule-based toolchains don't work with rules_foreign_cc

[davidbalbert]

This is probably a bug with rules_foreign_cc, but I'm not sure how you'd go about fixing it, so I'm posting it here.

Rules_foreign_cc's configure_make rule sets the LD environment variable before calling ./configure. The value of LD is set from cc_toolchain.ld_executable, which is set from tool_paths. Because the new rule-based toolchain API uses action configs instead of tool paths, I can't use it to create a toolchain that works with rules_foreign_cc.

This was introduced to rules_foreign_cc in bazel-contrib/rules_foreign_cc#1068. The justification for the behavior was:

Some configure + make systems look for the ld binary that is supposed to be used, and invoke it directly for various reasons.

[...]

This grabs the ld executable directly from cc_toolchain.ld_executable rather than using something like cxx_linker_executable, because the former returns CC generally, but LD should be the linker directly.

Is there a good way to fix this in rules_foreign_cc now, or does rules_cc need to be changed (a new action type perhaps?) to make this work?

This issue is being tracked in bazel-contrib/rules_foreign_cc#1160. I can provide a simple example if necessary.

I'm running Debian 12.8 on aarch64, Bazel 7.4.1, rules_cc 0.1.0 and rules_foreign_cc 0.13.0.

[armandomontanez]

I'd expect the ld binary to come from cc_common.get_tool_for_action(ACTION_NAMES.cpp_link_executable). I believe tool_paths is considered the legacy way to configure a toolchain.

Sorry for the delay in response.