Is there a way to review the result of a merge between two branches before actually merging them ?
When attempting to merge branch A to branch B, I usually checkout a temporary branch from B, merge it with branch A, then I'd create a diff patch, or just checkout to that temporary branch and check whether everything is working fine before merging A to B.
Does git provide a command or a feature that would accomplishes this?
As Marian Theisen suggested, you can do this to do the merge without committing
git merge --no-commit <branchname>
You can back out of that merge with
git reset --hard
Also, remember that it is always easy to back up in Git. You can do a full merge, including commit, inspect the complete result and if you change your mind you can
git reset --hard HEAD^
to throw away the merge and be back at the commit before the merge.
In fact, at any point during the merge resolution, you can do
git reset --merge
To abort the merge and throw away just the merge changes.