Use --features=external_include_paths for Bazel builds to allow angle-bracketed includes.

[fruffy]

Reintroduce the system includes and use a trick suggested in abseil/abseil-cpp#1637 (comment). We can add the feature flag --features=external_include_paths which enables system includes.

This is a newish feature: bazelbuild/bazel@08936ae

[smolkaj]

Nice find!

[smolkaj]

Do you now if everyone depending on p4c using bazel will also have to set --features=external_include_paths? Hopefully no?

[fruffy]

Do you now if everyone depending on p4c using bazel will also have to set --features=external_include_paths? Hopefully no?

The question is whether parameters defined in.bazelrc are respected by downstream dependencies. Unclear to me unfortunately.

[vlstill]

Do you now if everyone depending on p4c using bazel will also have to set --features=external_include_paths? Hopefully no?

The question is whether parameters defined in.bazelrc are respected by downstream dependencies. Unclear to me unfortunately.

(The Altera/Intel compiler is not using Bazel.)

[fruffy]

Do you now if everyone depending on p4c using bazel will also have to set --features=external_include_paths? Hopefully no?

abseil/abseil-cpp#1637 (comment) back to the drawing board...

On an unrelated note: Here is an amusing read of someone trying to fix Protobuf's quote includes: https://rachelbythebay.com/w/2024/04/29/pb/

[smolkaj]

The question is whether parameters defined in.bazelrc are respected by downstream dependencies. Unclear to me unfortunately.

Looks like you have already determined that the answer is likely no. We can also find out easily empirically, by running the following experiment:

• Revert your changes under bazel/example/
• Check if CI passes.

Note that bazel/example basically contains a "downstream project" depending on p4c, so building it tests exactly this sort of thing.

[fruffy]

The question is whether parameters defined in.bazelrc are respected by downstream dependencies. Unclear to me unfortunately.

Looks like you have already determined that the answer is likely no. We can also find out easily empirically, by running the following experiment:

* Revert your changes under `bazel/example/`

* Check if CI passes.

Note that bazel/example basically contains a "downstream project" depending on p4c, so building it tests exactly this sort of thing.

Did that and, as expected, the test fails. Unfortunate.