go-delve/delve · error

Neither DELVE_EDITOR or EDITOR is set

Error message

Neither DELVE_EDITOR or EDITOR is set

What it means

Delve's 'edit' command launches an external editor, which it locates via the DELVE_EDITOR environment variable, falling back to EDITOR. If both are empty there is no program to spawn, so getEditorName returns this error before attempting any execution.

Source

Thrown at pkg/terminal/command.go:2023

}

func tracepoint(t *Term, ctx callContext, args string) error {
	if ctx.Prefix == onPrefix {
		if args != "" {
			return errors.New("too many arguments to trace")
		}
		ctx.Breakpoint.Tracepoint = true
		return nil
	}
	_, err := setBreakpoint(t, ctx, true, args)
	return err
}

func getEditorName() (string, []string, error) {
	var editor string
	if editor = os.Getenv("DELVE_EDITOR"); editor == "" {
		if editor = os.Getenv("EDITOR"); editor == "" {
			return "", nil, errors.New("Neither DELVE_EDITOR or EDITOR is set")
		}
	}

	editorParts := strings.Fields(editor)
	editor = editorParts[0]

	var userArgs []string
	if len(editorParts) > 1 {
		userArgs = editorParts[1:]
	}

	return editor, userArgs, nil
}

func runEditor(args ...string) error {
	editor, userArgs, err := getEditorName()
	if err != nil {
		return err

View on GitHub (pinned to a23773e6c3)

Solutions

1. Export EDITOR before starting delve: e.g. export EDITOR=vim.
2. Set DELVE_EDITOR if you want a delve-specific editor that differs from EDITOR.
3. If you set VISUAL, also mirror it to EDITOR since Delve does not read VISUAL.

Example fix

// before (shell)
dlv debug
(dlv) edit
// error: Neither DELVE_EDITOR or EDITOR is set
// after
export EDITOR=vim
dlv debug
(dlv) edit

editor := os.Getenv("DELVE_EDITOR")
if editor == "" {
    editor = os.Getenv("EDITOR")
}
if editor == "" {
    return errors.New("set EDITOR before running dlv edit")
}

if _, _, err := getEditorName(); err != nil {
    if strings.Contains(err.Error(), "DELVE_EDITOR or EDITOR") {
        os.Setenv("EDITOR", "vi") // fallback editor
    }
    return err
}

When it happens

Trigger: Running the 'edit' command in the Delve terminal on a machine where neither DELVE_EDITOR nor EDITOR is exported in the shell environment that launched dlv.

Common situations: CI containers, minimal Docker images, fresh servers, or systemd-launched shells where EDITOR is never set; also users who set VISUAL only, which Delve does not consult.

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

• command not available
• unknown config parameter
• not documented
• you must specify a thread
• too many arguments to goroutine

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/3cf73c9dfd599ce3. Report an issue: GitHub.