What causes "Can't load git var: GIT_EDITOR" in mislav/hub?

Export an editor: export GIT_EDITOR=vim (or core.editor in git config)

Can't load git var: GIT_EDITOR

Error message

Can't load git var: GIT_EDITOR

What it means

Editor() runs `git var GIT_EDITOR` to resolve which editor git would use, then expands any env vars in the result. The error is thrown when that subprocess fails — i.e. git could not resolve GIT_EDITOR (often because neither GIT_EDITOR, core.editor, VISUAL, EDITOR is set and git falls back to a check that fails).

Source

Thrown at git/git.go:112

		return false
	}

	s := []string{dir}
	s = append(s, segments...)
	path := filepath.Join(s...)
	if _, err := os.Stat(path); err == nil {
		return true
	}

	return false
}

func Editor() (string, error) {
	varCmd := gitCmd("var", "GIT_EDITOR")
	varCmd.Stderr = nil
	output, err := varCmd.Output()
	if err != nil {
		return "", fmt.Errorf("Can't load git var: GIT_EDITOR")
	}

	return os.ExpandEnv(firstLine(output)), nil
}

func Head() (string, error) {
	return SymbolicRef("HEAD")
}

// SymbolicRef reads a branch name from a ref such as "HEAD"
func SymbolicRef(ref string) (string, error) {
	refCmd := gitCmd("symbolic-ref", ref)
	refCmd.Stderr = nil
	output, err := refCmd.Output()
	return firstLine(output), err
}

// SymbolicFullName reads a branch name from a ref such as "@{upstream}"

View on GitHub (pinned to 5c547ed804)

Solutions

Export an editor: export GIT_EDITOR=vim (or core.editor in git config)
Set EDITOR/VISUAL in the environment (e.g. in Dockerfile or CI setup step)
Verify with `git var GIT_EDITOR` in the same shell
Alternatively use the EDITOR env var directly if the library consumer controls it

Example fix

// before: assume editor resolves
editor, _ := git.Editor()
// after: ensure an editor is configured
if os.Getenv("GIT_EDITOR") == "" && os.Getenv("EDITOR") == "" {
    os.Setenv("GIT_EDITOR", "vim")
}
editor, err := git.Editor()

Defensive patterns

Strategy: fallback

Validate before calling

if os.Getenv("GIT_EDITOR") == "" && os.Getenv("EDITOR") == "" && os.Getenv("VISUAL") == "" {
    os.Setenv("GIT_EDITOR", "vim") // or vi/nano depending on platform
}

Try / catch

editor, err := git.Editor()
if err != nil {
    editor = os.Getenv("EDITOR")
    if editor == "" { editor = "vi" }
}

Prevention

Set GIT_EDITOR or EDITOR in CI images and containers
Configure core.editor in git config for reproducible behavior
Use non-interactive editors (true/vim -e) in automated flows
Test `git var GIT_EDITOR` in deployment environments

When it happens

Trigger: Calling git.Editor() (directly or via TestGitEditor/NewEditor) in an environment where `git var GIT_EDITOR` exits non-zero: no editor env var configured and no sensible default available.

Common situations: CI/headless servers with no EDITOR or GIT_EDITOR set; Docker containers; running under a service account with a minimal environment; git versions where `git var` errors instead of returning a default.

Understand the failure class

Background: "environment variable is not set" and "Missing keys in environment" errors: what missing required env var messages mean and how to fix them — this error's family across 28 libraries.

Related errors

AI-assisted analysis of mislav/hub@5c547ed804 (2026-09-01). Data as JSON: /api/errors/03436c071a8c12f2. Report an issue: GitHub.