git Editor Configurations

tl;dr

• There are two ways to set git editor:
  • git config
  • the shell’s GIT_EDITOR environment variable
• The shell environment variable takes preference over the git config value.

I want to share how I debugged a git editor configuration issue where an editor other than the one set in git config core.editor. I will walk through the situation and how I solved it.

By reading this, one will learn there is more than one way to configure the default editor for git and there is a configuration order. Next time you encounter an issue, here is another possible area to investigate.

This article will take about two minutes to read.

source and more information

Introduction

Are you having problems with the Atom editor modifying your git commit message? Not able to git commit --amend because the editor just opens up and the commit message template is not there?

I found this when pairing with a coworker and they use Atom as their default editor. Everyone on the team uses a different editor, it’s either great or hell. I embrace it as there’s always something to learn and it keeps me humble. This is a situation where I learned something unexpected because of a different editor.

This issue with the git commit message happened when I wanted to amend a previous git commit message on a coworker’s computer.

Executing git commit --amend opened up atom, her configured git editor (in: git config core.editor) but it would show nothing.

Searching around, I discovered the issue was the editor value, atom --wait is the correct parameter to use instead of just atom. tip

Setting git config core.editor='atom --wait' should have changed the situation, the problem still persisted when running git commit --amend

Set it to something else!

I resorted to changing the git editor to vim, something different. A change of that level must work, right?

Well, when setting git config core.editor='vim', atom still opened when executing: git commit --amend.

HUH!?

(and the editor didn’t have the commit message!)

Why was atom still launching, even when configuring the git editor to be vim?! The git editor value must be coming from somewhere else! (Either that, or someone aliased vim -> atom, which now that I think about it, would make great prank.)

I had a hunch that this issue was beyond just the git config, as changing the editor to vim did not change anything and vim was really vim.

Beyond git config

I looked at the environment variables set in the bash profile and noticed:

$ env
...
GIT_EDITOR=atom
...

Eureka! This would explain why changing the git config editor, atom still launches!

When changing the GIT_EDITOR value to:

$ export GIT_EDITOR=vim
$ git commit --amend

vim finally shows up with the git commit message to edit.

Lesson

There are two ways to configure the git editor through:

1. The git config that controls all parts of git.
2. The environment variable: GIT_EDITOR that is part of the shell variables.

As someone that works with git, I never expected a shell environment to override the git config setting. Now I learned the order git evaluates for its editor, even above the program’s own internal value.

Note: Configuring GIT_EDITOR='atom --wait' also fixed the original issue.