git-ff : simple fast forward without working tree

Fast forward branches without checking-out, works by looking if the branch is an ancestry of the tracking branch and upating the ref.

• can fast-forward branches on a bare repository
• can fast-forward all tracking branches possible
• does not do anything when no fast forward (merge or push required)

use an alias in .gitconfig:

[alias]
    ff = !git-ff "$@"

examples

fast forward current branch:

$ git ff
heads/v1.8           [remotes/ompi/v1.8]       : behind 4
  fast-forwarding d241021..e86824f

fast forward all branches possible:

$ git ff --all
heads/master         [remotes/ompi/master]     : behind 22
  fast-forwarding c33b786..7068846
heads/v1.8           [remotes/ompi/v1.8]       : behind 4
  fast-forwarding d241021..e86824f
heads/v1.8-mine      [remotes/release/v1.8]    : ahead 1
  you can push: git push release heads/v1.8-mine:v1.8

see which branches can advance (like in git branch -avv)

$ git ff --status
heads/master         [remotes/ompi/master]     : behind 22
heads/v1.8           [remotes/ompi/v1.8]       : behind 4
heads/v1.8-mine      [remotes/release/v1.8]    : ahead 1