I have had this issue recently, with a git branch which did not want to to react to push. That's what a was having:
$ git [email protected]'s password Counting objects: 5, done.
Delta compression using up to 2 threads.
ng objects: 100% (3/3), done.
Writing objects: 100% (3/3), 303 bytes, done.
Total 3 (delta 2), reused 0 (delta 0)
error: unable to create temporary sha1 filename ./objects/17: Permission denied
fatal: failed to write object