eldev

name	eldev
description	Configure and build Elisp projects using Eldev. Manage dependencies from package archives, Git repos, and local sources. Run tests with ERT, byte-compile projects, launch interactive Emacs sessions with project context, and manage loading modes. Use when user mentions eldev, an Eldev file, or an Elisp project with dependencies.

Eldev

Quick start

• eldev init — create Eldev file
• Eldev = project config (Elisp, version-controlled)
• Eldev-local = user-local overrides (not version-controlled; add to .gitignore)
• eldev help / eldev help COMMAND — built-in docs

Project setup

Default: use MELPA only. In Eldev:

(eldev-use-package-archive 'melpa)

VC repositories:

(eldev-use-vc-repository 'dep-name :github "USER/REPO")

Local sources (in Eldev-local only):

(eldev-use-local-sources "~/path/to/dep")

Extra deps for specific commands:

(eldev-add-extra-dependencies 'test 'some-package)
(eldev-add-extra-dependencies 'emacs 'evil)

Testing (ERT)

eldev test              # all tests
eldev test my-test      # specific test by name
eldev -p test           # test as installed package

Interactive Emacs

eldev emacs             # clean session with project
eldev emacs -nw         # terminal mode
eldev eval "(foo 42)"   # quick eval

Running with evil

In Eldev-local:

(eldev-add-extra-dependencies 'emacs 'evil)

(add-hook 'after-init-hook
          (lambda () (require 'evil) (evil-mode 1)))

Then eldev emacs -nw.

Loading modes

• -p / --packaged = build + install as package (closest to user install).
• -c / --byte-compiled = compile all files first.
• -o / --compiled-on-demand = compile only when loaded (large projects).

Nix shell

nix-shell --run "eldev test"
nix develop -c eldev test

Targeting a specific Emacs binary

Eldev picks the Emacs to run from the EMACS (or ELDEV_EMACS) environment variable, falling back to emacs on PATH. Set it inline — no shell pollution:

EMACS=/path/to/emacs eldev test

Combined with a Nix store path:

EMACS=/nix/store/83arrrf333lc4qwnzjgvwqhwvy4n9ksm-emacs-29.4/bin/emacs eldev test

Compare two versions side by side:

EMACS=/nix/store/.../bin/emacs eldev test 2>&1 | tail -5
echo "=== default ==="
eldev test 2>&1 | tail -5

Probing internals via a temp file

For ad-hoc debugging — write a small Elisp probe to /tmp and load it with eldev emacs --batch:

cat > /tmp/probe.el <<'EOF'
;; your probing code here
(message "hello from %s" emacs-version)
EOF

EMACS=/path/to/emacs eldev emacs --batch -l /tmp/probe.el

• 'EOF' (quoted marker) prevents shell expansion.
• EMACS=... targets a specific version without touching shell state.
• eldev emacs loads the project and all deps on load-path.
• --batch: headless, exits when done, output to stdout.
• -l /tmp/probe.el loads the file as the last init step.

For one-liners, --eval '(form)' works but nested quotes get painful. Multi-line → heredoc.

Pitfalls

• Smart quotes. Elisp only recognises straight ' (apostrophe). No ´ or typographic quotes.
• Cleanup. rm /tmp/probe*.el when done.
• Env vs Eldev form. EMACS=path eldev … sets the binary; eldev --setup '(setq …)' sets Eldev options. Different mechanisms.

Quick reference

Command	Purpose
eldev deps / eldev dtree	List dependencies / tree
eldev upgrade	Upgrade deps
eldev upgrade-self	Upgrade Eldev
eldev lint / eldev doctor	Lint / check health

Troubleshooting: -t / --trace shows what Eldev does; -d / --debug shows stacktraces. -X / --external uses preinstalled deps (skip isolation).