hermetic builds

[cc10512]

Describe the bug
Hermetic builds are a bit more strict with includes and paths.

Additional context
I have a potential PR that consists of a couple of commits enabling such builds. Two main issues addressed in different commits:

1. adding missing includes for features used in header files.
2. add arguments to generative scripts that allow separating the location of the script from the location of the input. Or in other words, allow inputs to be specified explicitly on the command line. In addition a few more suggestions from static checking Python tools.

Please let me know it this is of interest.

[MikePopoloski]

Yes, I would accept a PR for this, though I can't guarantee it will remain buildable if there's no CI job ensuring that the hermetic build continues to work.

[cc10512]

Thanks for your reply. You make a good point of maintenance.

I believe we have two options:

1. add a bazel BUILD file that would do CI for this. Not ideal to have two parallel systems, but not a huge maintenance effort once we pass the initial effort (and yes, we could contribute that initial work).
2. add a set of stricter compile options. The current tree builds with:

  add_compile_options(
      -Wall
      -Wextra
      -pedantic
      -Werror
      -Wno-ctad-maybe-unsupported
      -Wno-ignored-qualifiers
      -Wno-non-virtual-dtor
      -Wno-pessimizing-move
      -Wno-reorder-ctor
      -Wno-self-assign-overloaded
      -Wno-sign-compare
      -Wno-unused-function
      -Wno-unused-lambda-capture
      -Wno-unused-parameter
      -Wno-unused-private-field
      -Wno-unused-variable
      -Wno-unused-but-set-variable
)

We can then incrementally remove all the disabled warnings and get to a clean build with the most pedantic set of warnings. This second option does not address the file locations and Python type checking. But together with the PR I suggested, gets us quite most of the way -- the C++ source won't need any additional maintenance work.

Please let me know what you think.

[MikePopoloski]

Hmm, I'm not excited about having a second parallel build system to maintain, even if you contribute the initial implementation. I don't know much about Bazel; is it unable to consume 3rd party libraries that have a cmake build system? It's also unclear to me why the pedantic set of warnings is necessary for hermetic builds.

Maybe let's just start with your PR and we can see how much pain there is for you to maintain that over time. It's not like I'm going to go out of my way to break hermetic builds for you in the future.

[cc10512]

Fair. I opened #1160.

The pedantic warnings was just a suggestion driven by the side-effects of using a different build system with stricter defaults.