Jeff King <peff@xxxxxxxx> writes: > When a ref maps to a commit that is neither rewritten nor kept by > filter-branch (e.g., because it was eliminated by rev-list's pathspec > selection), we rewrite it to its nearest ancestor. > > Since the initial commit in 6f6826c52b (Add git-filter-branch, > 2007-06-03), we have warned when there are multiple such ancestors in > the map file. However, the warning code is impossible to trigger these > days. Since a0e46390d3 (filter-branch: fix ref rewriting with > --subdirectory-filter, 2008-08-12), we find the ancestor using "rev-list > -1", so it can only ever have a single value. ;-)
