Dependency generator exports sometimes dependency names with trailing white spaces. This can confuse dependency filters defined in package spec file. Example: package perl-Memoize-ExpireLRU, commit 105c1eeeb397f2db55eeb0b070d99432f2dcecac, rpm-4.9.1-2.fc16: Unversioned Provides perl(Memoize::ExpireLRU) has two trailings spaces.
Where exactly are you seeing this trailing whitespace? If it's 'rpm -qp --provides' output, the trailing whitespace is not really there, it's just an (unwanted) artifact of how --provides/--requires etc are implemented (see bug 717534).
The space was passed to dependency filters defined in spec file too (both the old %filter_from_* and the new __*_exclude). However I cannot reproduce it now with rpm-4.9.1.1-2.fc17.x86_64. We have lot of such "\s*" hacks in perl-* spec files, so this is not my imagination. Maybe it has been fixed meanwhile somehow. I will give a try with older rpm later.
I'm not saying you're imagining things, but with the myriad combinations of perl dependency extraction and filtering mechanisms that exist (including the alternative depgen from perl-rpm-build-perl), without an exact reproducer looking into this would be just chasing ghosts.
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
Feel free to reopen if you come up with a reproducer, but without one chasing this would be hopeless waste of time.