Build order and building against dependency packages

[lazka]

Just a braindump:

• If a package A fails to build any packages B depending on it needs to be skipped until that is fixed (or overruled somehow). So that any of B don't build against the wrong version of A.
• If a package A that is about to get build depends on any package B that was build before in the same run then B needs to be made installable. So that A builds against the right version of B.
• If a package A that is about to get build depends on any package B already in staging then that package needs to be downloaded and be made available for installation. Again, so that A builds against the right version of B.

Example scenario:

• We upload Python 3.9 and bump pkgrel of various Python packages.
• All Python packages need to be build against the new Python or they will be broken.

What we need:

• Grouping of related packages in the API
• Create local pacman repos during the build and fill them with packages from the same run and from related packages already in staging.

[lazka]

The API part is now done in https://github.com/msys2/msys2-web/commit/9dc052cf9198. Each package in the queue contains a list of packages in the same queue it depends on.

[lazka]

This is now implemented

[lazka]

As an example: https://github.com/msys2/msys2-devtools/runs/942425357?check_suite_focus=true

• python-patiencediff installs python from staging and then builds against it
• mingw-w64-rav1e gets skipped because cargo-c fails to build