I believe there's currently no check to make sure there's no conflicting URLs between auto and manual-custom URLs. Also custom URLs might not even check to see if another custom url was already used.
A possible solution is to, internally, make all URLs custom URLs; that is, auto-assign slugs instead of base36 translating to/from a numerical id. A migration could be made for existing auto URLs.
thanks for the info, definitely sounds like a reasonable method
it will now error out if you try to use a in-use custom url, still allows auto/custom conflicts
My dev branch has a migration that identifies conflicts and gives everything explicit slugs. Still need to rewrite automatic slug generation.
alanhogan/lessnmore@c2e750c completely resolves this issue, and a related one regarding custom URLs in the stats table.
merged alanhogan's fork, so this issue should be resolved