Feature: meson toolchain

[SSE4]

related: #7155 #7075

/cc @TheQwertiest @KristianJerpetjon @kristofferkoch

this is an early WIP - mostly to discuss the interface and implementation details.
unfortunately I cannot get even basic things of meson native file to work according to the documentation - meson appears to ignore project-specific options and built-in options specified in the native file.
meson issues: mesonbuild/meson#7697 mesonbuild/meson#7699
as things above didn't work for me, there are not many things tested yet.

open questions:

• should we manage directories (such as libdir, bindir and so on)?
• what to do with custom build types? (reject/specify custom/specify nothing)

Changelog: Feature: meson toolchain
Docs: conan-io/docs#1943

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[memsharded]

This is looking very good, a great good first step to start improving Meson integration via toolchains.

[SSE4]

@memsharded thanks, the bad thing is probably it will be blocked until meson 0.56 release as most of things in native/cross files right now don't work according to the documentation - values specified in toolchain are simply ignored...

[memsharded]

@memsharded thanks, the bad thing is probably it will be blocked until meson 0.56 release as most of things in native/cross files right now don't work according to the documentation - values specified in toolchain are simply ignored...

Uhm... I guess that we should wait, yes, and plan for the future of Meson, not the current state, because it is still not stable 0.X release. Is there an estimated date for 0.56? It would be great to know how fast the community is upgrading to newer Meson versions too.

[SSE4]

asked at mesonbuild/meson#7699 (comment) about ETA for 0.56

[SSE4]

update: meson 0.56rc1 is out, and I expect release in several days, so I am going back to refresh this PR

[SSE4]

updated, works locally with meson 0.56rc2. please review.

[SSE4]

@jgsogo @memsharded how can I ensure the right meson is installed on CI?

ERROR: Could not find a version that satisfies the requirement meson>=0.56.0rc2 (from -r conans/requirements_dev.txt (line 6)) (from versions: 0.29.0.dev1, 0.29.0.dev2, 0.29.0.dev3, 0.29.0, 0.30.0, 0.31.0, 0.32.0, 0.33.0, 0.34.0, 0.35.0, 0.35.1, 0.36.0, 0.37.0, 0.37.1, 0.38.0, 0.38.1, 0.39.0, 0.39.1, 0.40.0, 0.40.1, 0.41.0, 0.41.1, 0.41.2, 0.42.0, 0.42.1, 0.43.0, 0.44.0, 0.44.1, 0.45.0, 0.45.1, 0.46.0, 0.46.1, 0.47.0, 0.47.1, 0.47.2, 0.48.0, 0.48.1, 0.48.2, 0.49.0, 0.49.1, 0.49.2, 0.50.0, 0.50.1, 0.51.0, 0.51.1, 0.51.2, 0.52.0, 0.52.1, 0.53.0)

locally, seems to be working with requirements_dev.txt adding meson>=0.56.0rc2

[memsharded]

Very good job. Check the comments, and lets have this merged in Conan 1.32

[memsharded]

All this was not strictly necessary, as Meson only works with Py3, but not necessary to change.

[SSE4]

meson yes, but conan works with 2.x and 3.x, and they may use different interpreters (e.g. conan might use pyinstaller's one)

[memsharded]

Merged!

Note that in #8096, it will be moved to the new from conan.tools.meson import MesonToolchain.