Required meson version is higher then indicated

[Christian]

In the docs it is indicated that meson 0.47 is ok to build where in fact 0.56 is required:

test/meson.build:41: WARNING: Project targets '>= 0.47.0' but uses feature introduced in '0.56.0': meson.project_source_root.

The change was introduced here #1072 by @gizahNL

[Eli Schwartz]

If it's desirable to continue supporting very old versions of Meson, then meson.source_root() can be used. It's a bad, deprecated name that functions identically, but it is not deprecated until 0.56.0, since that's the first version that has a replacement.

[Christian]

There is probably some if way to support old and new versions here. But the current master branch needs 0.56 to compile.

[Gijs Peskens]

If it's desirable to continue supporting very old versions of Meson, then meson.source_root() can be used. It's a bad, deprecated name that functions identically, but it is not deprecated until 0.56.0, since that's the first version that has a replacement.

iirc meson.source_root() actually will point to the root of the top project, and would still break if libvmaf was used as a meson subproject. Usage in this case is only relevant to tests though, so would imho be less relevant to sub projects.

[Eli Schwartz]

... that would be my late at night brain at work. :(

For the subproject source root, a common tactic for backwards compat is to save meson.current_source_dir() to a variable in the top-level meson.build file.

[Kyle Swanson]

I think it's OK to bump the minimum required meson version. >= 0.56.1 would probably work.

[Kyle Swanson]

#1094 is merged, closing this.

[Christian]

@kylophone added a PR for the docs.