加载并激活Emacs package.el

Question

I have something like (to be simplify)

(require 'package)

(setq package-archives
      '(("org"          . "http://orgmode.org/elpa/")
        ("melpa"        . "http://melpa.org/packages/")
        ("melpa-stable" . "http://stable.melpa.org/packages/")
        ("gnu"          . "http://elpa.gnu.org/packages/")))

(setq package-enable-at-startup nil)
(package-initialize t)

(unless (package-installed-p 'use-package)
  (package-refresh-contents)
  (package-install 'use-package))

(let ((default-directory (expand-file-name user-emacs-directory "elpa")))
 (normal-top-level-add-subdirs-to-load-path))

(require 'use-package)

(use-package helm
  :ensure t
  :commands (helm-M-x
         helm-mini
         helm-find-files
         helm-show-kill-ring)
  :init
  (add-hook 'after-init-hook 'helm-mode)

  :config
    (helm-autoresize-mode 1))

in my .emacs . But I was told that Symbol's function definition is void: helm-mode after startup emacs.

After reading the manual of Packaging Basics and this answer , I find I still don't understand the mechanism of package.el .

I notice that the words load and activate are used in the manual, I suppose that load is 'Emacs adds the package's content directory to load-path, and evaluates the autoload definitions in name-autoloads.el.' and activate is to 'fully require '. I know if I change (package-initialize t) into (package-initialize) everything will be fine.

I confirm that something like "/Users/gaki/.emacs.d/elpa/helm-20160112.258" is in load-path and helm-mode is autoload . Isn't it can be autoload and even in the after-init-hook ?

Answer 1

A look at the code for package-activate and its helper package-activate-1 shows that a package's autoloads file is not loaded unless the package has been 'activated'.

You've told Emacs not to activate any packages by using (package-initialize t) , and you've prevented it from activating them after loading your init file with (setq package-enable-at-startup nil) , so none of your package autoloads are known to Emacs.

I suggest changing (package-initialize t) to (package-initialize) .

Note that the documentation you linked to describes the NO-ACTIVATE argument as "for internal use only".

ps Activation does not require the package features -- there would be no purpose to the autoloads if it did -- so this should not take a very significant amount of time, unless perhaps you have a really large number of packages? What kind of time difference are you actually seeing here? ( https://emacs.stackexchange.com/a/19263/454 may help with answering that.)