Meson version policy

Aims

• Stable versions of GLib should be buildable from source on the majority of systems which are still supported by their vendors, without requiring the user to manually build a number of dependencies
• Unstable versions of GLib should be able to take advantage of newer build system features where they would make maintenance of GLib easier, without prejudicing the other aims

Policy

• Stable branches of GLib will not change their Meson dependency after the first release of that stable series
• Unstable branches of GLib can bump their Meson dependency if
  • at least that version of Meson is currently available in the freedesktop SDK; and
  • at least that version of Meson is currently available in Debian Testing, or
  • the Python version required by the new Meson dependency is available in Debian Stable and the oldest currently-supported Ubuntu LTS
• The version of Meson used by GLib should be pinned and pre-installed in the CI Dockerfiles so that GLib is guaranteed to be built against the expected version

The reasoning behind allowing a version bump if the Python which Meson depends on is available in Debian Stable is that it’s straightforward to install a more recent Meson version using pip.

The reasoning behind requiring the version of Meson to be available in the freedesktop SDK is that it is used to build GLib on nightly pipelines in gnome-build-meta, which is used to test GLib against multiple third party projects.