How to setup xcode related env in aspect rule?

[kkpattern]

Hi, I'm trying to use bazel_clang_tidy to run clang-tidy on my objc_library targets. Clang-tidy failed to find the system headers. I think this is because bazel use __BAZEL_XCODE_SDKROOT__ in compile flags then replace it later with SDKROOT in wrapped_cc. However, when I build the aspect rule, the SDKROOT env is not set. Is there a way I can setup XCode related env in aspect rule?

Thanks!

[keith]

I haven't done this with aspects before but you should checkout this pattern

rules_apple/apple/testing/default_runner/watchos_test_runner.bzl

Lines 108 to 113 in 89b1094

	"_xcode_config": attr.label(
	default = configuration_field(
	fragment = "apple",
	name = "xcode_config_label",
	),
	),

and how that is used. You might have to do the replacements yourself depending on the case.

[kkpattern]

I haven't done this with aspects before but you should checkout this pattern

rules_apple/apple/testing/default_runner/watchos_test_runner.bzl

Lines 108 to 113 in 89b1094

	"_xcode_config": attr.label(
	default = configuration_field(
	fragment = "apple",
	name = "xcode_config_label",
	),
	),

and how that is used. You might have to do the replacements yourself depending on the case.

Thanks! It worked!

So when execute actions bazel will put SDKROOT into env. But it requires xcode config related env variables are set first. So we need first to add _xcode_config attr and apple fragment to the aspect rule:

clang_tidy_aspect = aspect(
    implementation = _clang_tidy_aspect_impl,
    fragments = ["cpp", "apple", "objc"],
    attrs = {
        ...
        "_xcode_config": attr.label(
            default = configuration_field(
                fragment = "apple",
                name = "xcode_config_label",
            ),
        ),
    },
)

Then we get the required env variables by:

    env = {}
    xcode_config = ctx.attr._xcode_config[apple_common.XcodeVersionConfig]
    env.update(apple_common.apple_host_system_env(xcode_config))
    env.update(apple_common.target_apple_env(xcode_config, ctx.fragments.apple.single_arch_platform))

Finally, we put the env into action.run:

    ctx.actions.run(
        ...
        env = env,
    )

Now we have SDKROOT and DEVELOPER_DIR setup for actions.

I also found apple_support already took care of this for us. I encounter a problem when trying apple_support so end up doing it on my own. But if anyone need to run actions with SDKROOT and DEVELOPER_DIR can give it a try.

@keith thanks for your help!