1 files changed, 3 insertions, 0 deletions
diff --git a/git-debrebase b/git-debrebase
index 059d02b..d80c8d3 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -2416,6 +2416,9 @@ sub begin_convert_from () {
 
     fail "ffq-prev exists, this is already managed by git-debrebase!"
 	if $ffq_prev && git_get_ref $ffq_prev;
+    snag 'already-converted',
+	"ahead of debrebase-last, this is already managed by git-debrebase!"
+	if $gdrlast && git_get_ref $gdrlast && is_fast_fwd $gdrlast, $head;
     return ($head, undef);
 }