"Package lacks a file header" when installing via package-install

[zakame]

I'd like to maintain external elisp the same way as regular {,M}ELPA packages, so I tried installing npm.el via package-install (through quelpa and use-package):

(use-package npm
  :quelpa (npm :fetcher github :repo "azer/npm.el"))

Alas, I met with this error:

Debugger entered--Lisp error: (error "Package lacks a file header")
  signal(error ("Package lacks a file header"))
  error("Package lacks a file header")
  package-buffer-info()
  byte-code("\303\304!�r�q\210\305\216  \306=\203��\307\n!\210\310 \2028�   \311=\2037�\312\n!\210\313 \210\314\315!\2032�\315\n!\2028�\315 \2028�\316+\207" [temp-buffer kind file generate-new-buffer " *temp*" ((byte-code "\301�!\203\n�\302�!\210\301\207" [temp-buffer buffer-name kill-buffer] 2)) single insert-file-contents package-buffer-info tar insert-file-contents-literally tar-mode help-function-arglist package-tar-file-info nil] 2)
  quelpa-get-package-desc("/home/zakame/src/emacs-for-javascript/.emacs.d/quelpa/packages/npm-20160218.355.el")
  quelpa-package-install((npm :fetcher github :repo "azer/npm.el"))
  quelpa((npm :fetcher github :repo "azer/npm.el"))
  apply(quelpa (npm :fetcher github :repo "azer/npm.el"))
  (progn (apply (quote quelpa) (quote ((npm :fetcher github :repo "azer/npm.el")))) (if (fboundp (quote npm-install)) nil (autoload (function npm-install) "npm" nil t)) (if (fboundp (quote npm-new)) nil (autoload (function npm-new) "npm" nil t)) (if (fboundp (quote npm-new-dependency)) nil (autoload (function npm-new-dependency) "npm" nil t)) (if (fboundp (quote npm-nodemon-exec)) nil (autoload (function npm-nodemon-exec) "npm" nil t)) (if (fboundp (quote npm-test)) nil (autoload (function npm-test) "npm" nil t)) (if (fboundp (quote npm-version)) nil (autoload (function npm-version) "npm" nil t)) (ignore (progn (let* ((name "M-n i") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-install) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-install))) (let* ((name "M-n n") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-new) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-new))) (let* ((name "M-n d") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-new-dependency) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-new-dependency))) (let* ((name "M-n e") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-nodemon-exec) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-nodemon-exec))) (let* ((name "M-n p") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-test) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-test))) (let* ((name "M-n v") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-version) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-version))))))
  eval((progn (apply (quote quelpa) (quote ((npm :fetcher github :repo "azer/npm.el")))) (if (fboundp (quote npm-install)) nil (autoload (function npm-install) "npm" nil t)) (if (fboundp (quote npm-new)) nil (autoload (function npm-new) "npm" nil t)) (if (fboundp (quote npm-new-dependency)) nil (autoload (function npm-new-dependency) "npm" nil t)) (if (fboundp (quote npm-nodemon-exec)) nil (autoload (function npm-nodemon-exec) "npm" nil t)) (if (fboundp (quote npm-test)) nil (autoload (function npm-test) "npm" nil t)) (if (fboundp (quote npm-version)) nil (autoload (function npm-version) "npm" nil t)) (ignore (progn (let* ((name "M-n i") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-install) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-install))) (let* ((name "M-n n") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-new) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-new))) (let* ((name "M-n d") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-new-dependency) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-new-dependency))) (let* ((name "M-n e") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-nodemon-exec) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-nodemon-exec))) (let* ((name "M-n p") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-test) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-test))) (let* ((name "M-n v") (key (if (vectorp name) name (read-kbd-macro name))) (kdesc (cons (if ... name ...) (quote nil))) (binding (lookup-key (or nil global-map) key))) (add-to-list (quote personal-keybindings) (list kdesc (quote npm-version) (if (numberp binding) nil binding))) (define-key (or nil global-map) key (quote npm-version)))))) nil)
  eval-last-sexp-1(nil)
  eval-last-sexp(nil)
  #<subr call-interactively>(eval-last-sexp nil nil)
  ad-Advice-call-interactively(#<subr call-interactively> eval-last-sexp nil nil)
  apply(ad-Advice-call-interactively #<subr call-interactively> (eval-last-sexp nil nil))
  call-interactively(eval-last-sexp nil nil)
  command-execute(eval-last-sexp)

Simply put, this means there's no metadata in npm.el yet that would allow package.el to build it as an Emacs package.

Let me put up a quick PR to add such metadata (as well as to make it ready for MELPA, maybe?)