bazel: Python semiwrap yml files are generated but expected to be modified

[ThadHouse]

A generated file that is expected to be user modified is extremely confusing and unfriendly to developers. Generated files should be immutable.

[virtuald]

Probably the generation step shouldn't happen automatically, but should be something the user should explicitly do.

[auscompgeek]

it doesn't happen automatically though? a bazel build cannot write to the source tree itself

[auscompgeek]

To the original concern, if the C++ header files had sufficient information to create the Python bindings, then the YAML files wouldn't exist in the first place.

If @ThadHouse can come up with an elegant solution to embed all the information required for the Python bindings into the C++ headers, I'm all ears.

[virtuald]

I don't want to put the information into the header, that would be really annoying

[auscompgeek]

that's why I said "elegant solution". I can't come up with any way that wouldn't be extremely annoying to work with

[pjreiniger]

Probably the generation step shouldn't happen automatically, but should be something the user should explicitly do.

The generation step is simply a unit test to make sure the yaml files aren't missing anything that was added / deleted. This happens in mostrobotpy too. It is just done after everything is built instead of whenever the build scheduler schedules it.

[virtuald]

Why did it delete something for Thad then?

In mostrobotpy it isn't ran when you build, only as a separate test.

[pjreiniger]

If I had to guess, he saw //wpilibc:write_robotpy-wpilib-update-yaml_test fail, and when it fails it says "to fix it run bazel run //wpilibc:write_robotpy-wpilib-update-yaml. Doing that step would delete / add / modify files

[pjreiniger]

Or applied the patch from a github actions failure.

The files definitely don't get modified without running an explicit action, so I would not classify this as a bazel or allwpilib problem. The fundamental way that they yaml files are used and generated is a semiwrap thing, and would be better reported there

[ThadHouse]

Yup, I applied the patch from GitHub actions, blindly because I thought that was what was needed.