Last modified: 2013-04-22 16:14:53 UTC
With the resolution of bug 18834, we go through some latest revisions and in meantime we may find there're less than $wgShowRollbackEditCount edits in total and all of the belong to a single author. In this case it may be better not to show a non-usable [rollback] link.
+1, came here to report this bug, glad to see it's already done.
https://gerrit.wikimedia.org/r/31312 Waiting for review...
Change has been merged and will be part of 1.21 (1.21wmf8).