Merge branch 'jc/checkout-merge-base'
[git/git.git] / git-rebase.sh
index b121f45..3de0942 100755 (executable)
@@ -34,6 +34,8 @@ set_reflog_action rebase
 require_work_tree
 cd_to_toplevel
 
+LF='
+'
 OK_TO_SKIP_PRE_REBASE=
 RESOLVEMSG="
 When you have resolved this problem run \"git rebase --continue\".
@@ -417,7 +419,27 @@ fi
 
 # Make sure the branch to rebase onto is valid.
 onto_name=${newbase-"$upstream_name"}
-onto=$(git rev-parse --verify "${onto_name}^0") || exit
+case "$onto_name" in
+*...*)
+       if      left=${onto_name%...*} right=${onto_name#*...} &&
+               onto=$(git merge-base --all ${left:-HEAD} ${right:-HEAD})
+       then
+               case "$onto" in
+               ?*"$LF"?*)
+                       die "$onto_name: there are more than one merge bases"
+                       ;;
+               '')
+                       die "$onto_name: there is no merge base"
+                       ;;
+               esac
+       else
+               die "$onto_name: there is no merge base"
+       fi
+       ;;
+*)
+       onto=$(git rev-parse --verify "${onto_name}^0") || exit
+       ;;
+esac
 
 # If a hook exists, give it a chance to interrupt
 run_pre_rebase_hook "$upstream_arg" "$@"