Add system_includes to cc_library/cc_binary #25751
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this is an alternative option to #25750 |
Previously even though the attribute was named `includes`, the paths added there were actually propagated through the `system_includes` attribute of compilation context. This lead to crosstools passing these flags with `-isystem` which was unexpected for first party code. Many non bazel-first projects have header directory structures that require custom include paths be propagated throughout the graph, the alternative to `includes` is to use `strip_include_prefix`. The downside of `strip_include_prefix` is that you add 1 include path per `cc_library`, even if the libraries are in the same package. With `includes` these are deduplicated. In the case of LLVM using `includes` reduced the number of search paths on the order of hundreds. If users want to use `-isystem` for third party code that uses `includes`, they can pass `--features=external_include_paths --host_features=external_include_paths` Fixes bazelbuild#20267
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unless there's strong support for this over #25750 im going to move forward with that other change instead. primarily i think that one is preferred since it's unlikely a library should set both |
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Previously even though the attribute was named
includes, the pathsadded there were actually propagated through the
system_includesattribute of compilation context. This lead to crosstools passing these
flags with
-isystemwhich was unexpected for first party code.Many non bazel-first projects have header directory structures that
require custom include paths be propagated throughout the graph, the
alternative to
includesis to usestrip_include_prefix. The downsideof
strip_include_prefixis that you add 1 include path percc_library, even if the libraries are in the same package. Withincludesthese are deduplicated. In the case of LLVM usingincludesreduced the number of search paths on the order of hundreds.
If users want to use
-isystemfor third party code that usesincludes, they can pass--features=external_include_paths --host_features=external_include_pathsFixes #20267