local head, the push fails.
reachable::
- An object is reachable from a ref/commit/tree/tag, if there is a
- chain leading from the latter to the former.
+ All of the ancestors of a given commit are said to be reachable from
+ that commit. More generally, one object is reachable from another if
+ we can reach the one from the other by a chain that follows tags to
+ whatever they tag, commits to their parents or trees, and trees to the
+ trees or blobs that they contain.
rebase::
To clean a branch by starting from the head of the main line of