hi
i add this, that i can do a link to the bug that is already known.
problem:
if files move between packages pacman doesn't recognize it and updates packages in wrong order.

example:
packaga A provides: testfile-A
package B provides: testfile-B
now testfile-A moves to package-B:
on upgrade this will happen:
package B gets first updated, provides testfile-A
after it package A gets updated --> testfile A gets removed
--> missing files will happen

problem is the upgrade order of packages.

hope it was clear enough :)