ENH: allow users to pass options directly to Meson

[FFY00]

Signed-off-by: Filipe Laíns lains@riseup.net

EDIT: closes gh-54

[dnicolodi]

Does this need to be mesonpy? I think we are settling to meson-python as project name and it is nice to try to be consistent. Actually, we could even think about using tool.meson.

[rgommers]

This is a good point, let's try and update it. We should get rid of mesonpy everywhere except for in the build-backend = 'mesonpy' hook line.

I'd prefer meson-python here.

[FFY00]

Whops, I missed this comment 😣

[doronbehar]

@FFY00 would it be possible to give an example of how to use --config-settings KEY=VALUE with this PR? I wish to test whether it's possible to compile scipy with --cross-file with this patch..

[FFY00]

It should be python -m build -C--cross-file=yourfile.

[doronbehar]

It should be python -m build -C--cross-file=yourfile.

Is -C equivalent to --config-settings? I don't understand what is this build module you refer to with python -m..

[eli-schwartz]

Is -C equivalent to --config-settings? I don't understand what is this build module you refer to with python -m..

https://github.com/pypa/build

[rgommers]

Great to see this land!

One comment left unaddressed, and let's do a few doc updates in a follow-up PR. @FFY00 are you planning to do that? If not I can do it - already have a need to point people to it:)

[rgommers]

It should be python -m build -C--cross-file=yourfile.

That seems wrong, I think it should be python -m build -Csetup_args="--cross-file=yourfile". If we want -C--cross-file to work, it looks like it should be special-cased like builddir.

This landed with underscores *_args, which is a little unusual for CLI arguments, so wanted to check that that was intended?

It's nontrivial to figure out the right invocations here, so we need quite a few examples in the docs. Here is another one:

pip install . --config-settings compile_args="-j1"

Another follow-up, unrecognized inputs should raise or give a warning, rather than be silently ignored. This will happily continue a build:

pip install . --config-settings nonsense=true

[rgommers]

This landed with underscores *_args, which is a little unusual for CLI arguments, so wanted to check that that was intended?

This was done in gh-218.

Another follow-up, unrecognized inputs should raise or give a warning, rather than be silently ignored.

This was done in gh-219.

I'll open a new issue for the rest.