Git for Pair Programming

Git commits can only have one author. However, there is a convention that multiple authors can be recorded by lines beginning with Co-authored-by: at the end of a commit message. This convention is now supported by GitHub so all the co-authors can share the internet points.

This POSIX shell git plugin makes it easy to manage pair programming sessions and automatically add the appropriate Co-authored-by trailers to your commit messages.

Installation

• Put the git-pair script somewhere in your $PATH.
• Put the prepare-commit-msg script in .git/hooks/ inside each of your repos.

That last step is a bit tedious. I suggest you create a shell alias like so:

alias git-pair-init="cp /somewhere/prepare-commit-msg .git/hooks"

Usage

$ git pair add rh "Robin Hood <[email protected]>"
$ git pair add mm "Maid Marion <[email protected]>"
$ git pair add ft "Friar Tuck <[email protected]>"
$ git pair add lj "Little John <[email protected]>"
$ git pair list
rh Robin Hood <[email protected]>
mm Maid Marion <[email protected]>
ft Friar Tuck <[email protected]>
lj Little John <[email protected]>

$ git pair show
No pairs currently set.
$ git pair set mm ft
$ git pair show
Maid Marion <[email protected]>
Friar Tuck <[email protected]>

$ git commit -m 'Something informative'
Committing with co-authors:
 + Maid Marion <[email protected]>
 + Friar Tuck <[email protected]>
[master d898f8d] Something informative
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 foo
$ git log -n1
commit d898f8d3d83759843d19bf71b78ce6089929ccce (HEAD -> master)
Author: Your Usual Git Username <user.email@gitconfig>
Date:   Sat Oct 27 14:17:30 2018 +0100

    Something informative

    Co-authored-by: Maid Marion <[email protected]>
    Co-authored-by: Friar Tuck <[email protected]>

Notes

The list of possible authors is stored in your global ~/.gitconfig. The list of currently active authors is stored in the local .git/config of your current repo. This way you can have different authors active in different repos at the same time, but you can share their contact details across all repos.

Although git pair add will always add to ~/.gitconfig, the list of possible authors is actually read from all your git configs: so a system administrator could pre-populate a list of possible authors to be shared by all users by putting them in /etc/gitconfig.