diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index b50c5d0ea3..47b48fbab6 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -2649,8 +2649,8 @@ __git_complete_config_variable_name ()
 		return
 		;;
 	branch.*)
-		local pfx="${cur%.*}."
-		cur_="${cur#*.}"
+		local pfx="${cur_%.*}."
+		cur_="${cur_#*.}"
 		__gitcomp_direct "$(__git_heads "$pfx" "$cur_" ".")"
 		__gitcomp_nl_append $'autoSetupMerge\nautoSetupRebase\n' "$pfx" "$cur_" "$sfx"
 		return