Git Fast Forward
$ git merge --ff-only origin/master
Joeyeyey
$ git merge --ff-only origin/masterA fast-forward merge can occur when there is a linear path
from the current branch tip to the target branch.
Instead of “actually” merging the branches,
all Git has to do to integrate the histories is move (i.e., “fast forward”)
the current branch tip up to the target branch tip.