NOTE: pacman v7 is currently in [libre-testing]; but it will be promoted to libre soon

from arch:

With the release of [version 7.0.0] pacman has added support fordownloading packages as a separate user with dropped privileges.

For users with local repos however this might imply that the downloaduser does not have access to the files in question, which can be fixedby assigning the files and folder to the alpm group and ensuring theexecutable bit (+x) is set on the folders in question.

$ chown :alpm -R /path/to/local/repo Remember to [merge the .pacnew] files to apply the new default.

Pacman also introduced [a change] to improve checksum stability forgit repos that utilize .gitattributes files. This might require aone-time checksum change for PKGBUILDs that use git sources.