Remove the :defer-install keyword

This may reappear as its own add-on to use-package in the future. See https://github.com/jwiegley/use-package/issues/442.

etc/USE-PACKAGE-NEWS

@@ -15,6 +15,9 @@
   
 - Emacs 24.3 or higher is now a requirement.
 
+- The `:defer-install` keyword has been remove. It may reappear as an add-on
+  module for use-package in a future release. See issue #442 for more details.
+
 ### Other changes
 
 - Upgrade license to GPL 3.

lisp/use-package/use-package.el

@@ -88,11 +88,6 @@ The check is performed by looking for the module using `locate-library'."
   :type 'boolean
   :group 'use-package)
 
-(defcustom use-package-always-defer-install nil
-  "If non-nil, assume `:defer-install t` unless `:defer-install nil` is given."
-  :type 'boolean
-  :group 'use-package)
-
 (defcustom use-package-always-ensure nil
   "Treat every package as though it had specified `:ensure SEXP`."
   :type 'sexp
@@ -140,7 +135,6 @@ the user specified."
 (defcustom use-package-keywords
   '(:disabled
     :pin
-    :defer-install
     :ensure
     :if
     :when
@@ -200,9 +194,8 @@ Must be set before loading use-package."
   "Function that ensures a package is installed.
 This function is called with four arguments: the name of the
 package declared in the `use-package' form; the argument passed
-to `:ensure'; the current `state' plist created by previous
-handlers; and a keyword indicating the context in which the
-installation is occurring.
+to `:ensure'; and the current `state' plist created by previous
+handlers.
 
 Note that this function is called whenever `:ensure' is provided,
 even if it is nil. It is up to the function to decide on the
@@ -210,50 +203,14 @@ semantics of the various values for `:ensure'.
 
 This function should return non-nil if the package is installed.
 
-The default value uses package.el to install the package.
-
-Possible values for the context keyword are:
-
-:byte-compile - package installed during byte-compilation
-:ensure - package installed normally by :ensure
-:autoload - deferred installation triggered by an autoloaded
-            function
-:after - deferred installation triggered by the loading of a
-         feature listed in the :after declaration
-:config - deferred installation was specified at the same time
-          as :demand, so the installation was triggered
-          immediately
-:unknown - context not provided
-
-Note that third-party code can provide other values for the
-context keyword by calling `use-package-install-deferred-package'
-with the appropriate value."
+The default value uses package.el to install the package."
   :type '(choice (const :tag "package.el" use-package-ensure-elpa)
                  (function :tag "Custom"))
   :group 'use-package)
 
-(defcustom use-package-pre-ensure-function 'ignore
-  "Function that is called upon installation deferral.
-It is called immediately with the first three arguments that
-would be passed to `use-package-ensure-function' (the context
-keyword is omitted), but only if installation has been deferred.
-It is intended for package managers other than package.el which
-might want to activate the autoloads of a package immediately, if
-it's installed, but otherwise defer installation until later (if
-`:defer-install' is specified). The reason it is set to `ignore'
-by default is that package.el activates the autoloads for all
-known packages at initialization time, rather than one by one
-when the packages are actually requested."
-  :type '(choice (const :tag "None" ignore)
-                 (function :tag "Custom"))
-  :group 'use-package)
-
 (defcustom use-package-defaults
   '((:config '(t) t)
     (:ensure use-package-always-ensure use-package-always-ensure)
-    (:defer-install
-     use-package-always-defer-install
-     use-package-always-defer-install)
     (:pin use-package-always-pin use-package-always-pin))
   "Alist of default values for `use-package' keywords.
 Each entry in the alist is a list of three elements. The first
@@ -639,80 +596,6 @@ manually updated package."
       (push pin-form body))          ; or else wait until runtime.
     body))
 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
-;;; :defer-install
-;;
-
-(defvar use-package--deferred-packages (make-hash-table)
-  "Hash mapping packages to data about their installation.
-
-The keys are not actually symbols naming packages, but rather
-symbols naming the features which are the names of \"packages\"
-required by `use-package' forms. Since
-`use-package-ensure-function' could be set to anything, it is
-actually impossible for `use-package' to determine what package
-is supposed to provide the feature being ensured just based on
-the value of `:ensure'.
-
-Each value is a cons, with the car being the the value passed to
-`:ensure' and the cdr being the `state' plist. See
-`use-package-install-deferred-package' for information about how
-these values are used to call `use-package-ensure-function'.")
-
-(defun use-package-install-deferred-package (name &optional context)
-  "Install a package whose installation has been deferred.
-NAME should be a symbol naming a package (actually, a feature).
-This is done by calling `use-package-ensure-function' is called
-with four arguments: the key (NAME) and the two elements of the
-cons in `use-package--deferred-packages' (the value passed to
-`:ensure', and the `state' plist), and a keyword providing
-information about the context in which the installation is
-happening. (This defaults to `:unknown' but can be overridden by
-providing CONTEXT.)
-
-Return t if the package is installed, nil otherwise. (This is
-determined by the return value of `use-package-ensure-function'.)
-If the package is installed, its entry is removed from
-`use-package--deferred-packages'. If the package has no entry in
-`use-package--deferred-packages', do nothing and return t."
-  (interactive
-   (let ((packages nil))
-     (maphash (lambda (package info)
-                (push package packages))
-              use-package--deferred-packages)
-     (if packages
-         (list
-          (intern
-           (completing-read "Select package: "
-                            packages nil 'require-match))
-          :interactive)
-       (user-error "No packages with deferred installation"))))
-  (let ((spec (gethash name use-package--deferred-packages)))
-    (if spec
-        (when (funcall use-package-ensure-function
-                       name (car spec) (cdr spec)
-                       (or context :unknown))
-          (remhash name use-package--deferred-packages)
-          t)
-      t)))
-
-(defalias 'use-package-normalize/:defer-install 'use-package-normalize-test)
-
-(defun use-package-handler/:defer-install (name keyword defer rest state)
-  (use-package-process-keywords name rest
-    ;; Just specifying `:defer-install' does not do anything; this
-    ;; sets up a marker so that if `:ensure' is specified as well then
-    ;; it knows to set up deferred installation. But then later, when
-    ;; `:config' is processed, it might turn out that `:demand' was
-    ;; specified as well, and the deferred installation needs to be
-    ;; run immediately. For this we need to know if the deferred
-    ;; installation was actually set up or not, so we need to set one
-    ;; marker value in `:defer-install', and then change it to a
-    ;; different value in `:ensure', if the first one is present. (The
-    ;; first marker is `:defer-install', and the second is `:ensure'.)
-    (plist-put state :defer-install (when defer :defer-install))))
-
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
 ;;; :ensure
@@ -729,66 +612,45 @@ If the package is installed, its entry is removed from
            (concat ":ensure wants an optional package name "
                    "(an unquoted symbol name)")))))))
 
-(defun use-package-ensure-elpa (name ensure state context &optional no-refresh)
-  (let ((package (or (and (eq ensure t) (use-package-as-symbol name))
-                     ensure)))
+(defun use-package-ensure-elpa (name ensure state &optional no-refresh)
+  (let ((package
+         (or (and (eq ensure t) (use-package-as-symbol name))
+             ensure)))
     (when package
       (require 'package)
-      (or (package-installed-p package)
-          ;; Contexts in which the confirmation prompt is bypassed.
-          (not (or (member context '(:byte-compile :ensure :config))
-                   (y-or-n-p (format "Install package %S?" package))))
-          (condition-case-unless-debug err
-              (progn
+      (unless (package-installed-p package)
+        (condition-case-unless-debug err
+            (progn
+              (when (assoc package (bound-and-true-p
+                                    package-pinned-packages))
+                (package-read-all-archive-contents))
+              (if (assoc package package-archive-contents)
+                  (package-install package)
+                (package-refresh-contents)
                 (when (assoc package (bound-and-true-p
                                       package-pinned-packages))
                   (package-read-all-archive-contents))
-                (if (assoc package package-archive-contents)
-                    (package-install package)
-                  (package-refresh-contents)
-                  (when (assoc package (bound-and-true-p
-                                        package-pinned-packages))
-                    (package-read-all-archive-contents))
-                  (package-install package))
-                t)
-            (error
-             (ignore
-              (display-warning 'use-package
-                               (format "Failed to install %s: %s"
-                                       name (error-message-string err))
-                               :error))))))))
+                (package-install package))
+              t)
+          (error
+           (ignore
+            (display-warning 'use-package
+                             (format "Failed to install %s: %s"
+                                     name (error-message-string err))
+                             :error))))))))
 
 (defun use-package-handler/:ensure (name keyword ensure rest state)
-  (let* ((body (use-package-process-keywords name rest
-                 ;; Here we are conditionally updating the marker
-                 ;; value for deferred installation; this will be
-                 ;; checked later by `:config'. For more information
-                 ;; see `use-package-handler/:defer-install'.
-                 (if (eq (plist-get state :defer-install)
-                         :defer-install)
-                     (plist-put state :defer-install :ensure)
-                   state))))
-    ;; We want to avoid installing packages when the `use-package'
-    ;; macro is being macro-expanded by elisp completion (see
-    ;; `lisp--local-variables'), but still do install packages when
-    ;; byte-compiling to avoid requiring `package' at runtime.
-    (cond
-     ((plist-get state :defer-install)
-      (push
-       `(puthash ',name '(,ensure . ,state)
-                 use-package--deferred-packages)
-       body)
-      (push `(,use-package-pre-ensure-function
-              ',name ',ensure ',state)
+  (let* ((body (use-package-process-keywords name rest state)))
+    ;; We want to avoid installing packages when the `use-package' macro is
+    ;; being macro-expanded by elisp completion (see `lisp--local-variables'),
+    ;; but still install packages when byte-compiling, to avoid requiring
+    ;; `package' at runtime.
+    (if (bound-and-true-p byte-compile-current-file)
+        ;; Eval when byte-compiling,
+        (funcall use-package-ensure-function name ensure state)
+      ;;  or else wait until runtime.
+      (push `(,use-package-ensure-function ',name ',ensure ',state)
             body))
-     ((bound-and-true-p byte-compile-current-file)
-      ;; Eval when byte-compiling,
-      (funcall use-package-ensure-function
-               name ensure state :byte-compile))
-     ;;  or else wait until runtime.
-     (t (push `(,use-package-ensure-function
-                ',name ',ensure ',state :ensure)
-              body)))
     body))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -1272,35 +1134,6 @@ representing symbols (that may need to be autloaded)."
 
 (defalias 'use-package-normalize/:defer 'use-package-normalize-predicate)
 
-(defun use-package--autoload-with-deferred-install
-    (command package-name)
-  "Return a form defining an autoload supporting deferred install."
-  `(let* ((load-list-item '(defun . ,command))
-          (already-loaded (member load-list-item current-load-list)))
-     (defun ,command (&rest args)
-       "[Arg list not available until function definition is loaded.]
-
-  \(fn ...)"
-       (interactive)
-       (if (bound-and-true-p use-package--recursive-autoload)
-           (use-package-error
-            (format "Autoloading failed to define function %S"
-                    ',command))
-         (when (use-package-install-deferred-package
-                ',package-name :autoload)
-           (require ',package-name)
-           (let ((use-package--recursive-autoload t))
-             (if (called-interactively-p 'any)
-                 (call-interactively ',command)
-               (apply ',command args))))))
-     ;; This prevents the user's init-file from being recorded as the
-     ;; definition location for the function before it is actually
-     ;; loaded. (Our goal is to leave the `current-load-list'
-     ;; unchanged, so we only remove the entry for this function if it
-     ;; was not already present.)
-     (unless already-loaded
-       (setq current-load-list (remove load-list-item current-load-list)))))
-
 (defun use-package-handler/:defer (name keyword arg rest state)
   (let ((body (use-package-process-keywords name rest
                 (plist-put state :deferred t)))
@@ -1318,13 +1151,7 @@ representing symbols (that may need to be autloaded)."
           (when (symbolp command)
             (append
              `((unless (fboundp ',command)
-                 ;; Here we are checking the marker value set in
-                 ;; `use-package-handler/:ensure' to see if deferred
-                 ;; installation is actually happening. See
-                 ;; `use-package-handler/:defer-install' for more information.
-                 ,(if (eq (plist-get state :defer-install) :ensure)
-                      (use-package--autoload-with-deferred-install command name)
-                    `(autoload #',command ,name-string nil t))))
+                 (autoload #',command ,name-string nil t)))
              (when (bound-and-true-p byte-compile-current-file)
                `((eval-when-compile
                    (declare-function ,command ,name-string)))))))
@@ -1374,15 +1201,10 @@ representing symbols (that may need to be autloaded)."
         (setq arg (cons :all arg)))
     (use-package-concat
      (when arg
-       (list (funcall (use-package-require-after-load arg)
-                      (macroexp-progn
-                       ;; Here we are checking the marker value for deferred
-                       ;; installation set in `use-package-handler/:ensure'.
-                       ;; See also `use-package-handler/:defer-install'.
-                       `(,@(when (eq (plist-get state :defer-install) :ensure)
-                             `((use-package-install-deferred-package
-                                'name :after)))
-                         (require (quote ,name) nil t))))))
+       (list (funcall
+              (use-package-require-after-load arg)
+              (macroexp-progn
+               `((require (quote ,name) nil t))))))
      body)))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -1441,12 +1263,6 @@ representing symbols (that may need to be autloaded)."
           `((eval-after-load ,(if (symbolp name) `',name name)
               ',(macroexp-progn config-body))))
 
-      ;; Here we are checking the marker value for deferred installation set
-      ;; in `use-package-handler/:ensure'. See also
-      ;; `use-package-handler/:defer-install'.
-      (when (eq (plist-get state :defer-install) :ensure)
-        (use-package-install-deferred-package name :config))
-
       (use-package--with-elapsed-timer
           (format "Loading package %s" name)
         (if use-package-expand-minimally
@@ -1709,10 +1525,8 @@ this file.  Usage:
                  `:magic-fallback', or `:interpreter'.  This can be an integer,
                  to force loading after N seconds of idle time, if the package
                  has not already been loaded.
-
 :after           Defer loading of a package until after any of the named
                  features are loaded.
-
 :demand          Prevent deferred loading in all cases.
 
 :if EXPR         Initialize and load only if EXPR evaluates to a non-nil value.

test/lisp/use-package/use-package-tests.el

@@ -194,28 +194,28 @@
     (match-expansion
      (use-package foo :ensure t)
      `(progn
-        (use-package-ensure-elpa 'foo 't 'nil :ensure)
+        (use-package-ensure-elpa 'foo 't 'nil)
         (require 'foo nil 'nil))))
 
   (let ((use-package-always-ensure t))
     (match-expansion
      (use-package foo :ensure t)
      `(progn
-        (use-package-ensure-elpa 'foo 't 'nil :ensure)
+        (use-package-ensure-elpa 'foo 't 'nil)
         (require 'foo nil 'nil))))
 
   (let ((use-package-always-ensure nil))
     (match-expansion
      (use-package foo :ensure nil)
      `(progn
-        (use-package-ensure-elpa 'foo 'nil 'nil :ensure)
+        (use-package-ensure-elpa 'foo 'nil 'nil)
         (require 'foo nil 'nil))))
 
   (let ((use-package-always-ensure t))
     (match-expansion
      (use-package foo :ensure nil)
      `(progn
-        (use-package-ensure-elpa 'foo 'nil 'nil :ensure)
+        (use-package-ensure-elpa 'foo 'nil 'nil)
         (require 'foo nil 'nil))))
 
   (let ((use-package-always-ensure nil))
@@ -230,7 +230,7 @@
     (match-expansion
      (use-package foo :load-path "foo")
      `(progn
-        (use-package-ensure-elpa 'foo 'nil 'nil :ensure)
+        (use-package-ensure-elpa 'foo 'nil 'nil)
         (eval-and-compile
           (add-to-list 'load-path ,(pred stringp)))
         (require 'foo nil 'nil))))
@@ -239,7 +239,7 @@
     (match-expansion
      (use-package foo :ensure nil :load-path "foo")
      `(progn
-        (use-package-ensure-elpa 'foo 'nil 'nil :ensure)
+        (use-package-ensure-elpa 'foo 'nil 'nil)
         (eval-and-compile
           (add-to-list 'load-path ,(pred stringp)))
         (require 'foo nil 'nil))))
@@ -248,7 +248,7 @@
     (match-expansion
      (use-package foo :ensure nil :load-path "foo")
      `(progn
-        (use-package-ensure-elpa 'foo 'nil 'nil :ensure)
+        (use-package-ensure-elpa 'foo 'nil 'nil)
         (eval-and-compile
           (add-to-list 'load-path ,(pred stringp)))
         (require 'foo nil 'nil))))
@@ -257,7 +257,7 @@
     (match-expansion
      (use-package foo :ensure t :load-path "foo")
      `(progn
-        (use-package-ensure-elpa 'foo 't 'nil :ensure)
+        (use-package-ensure-elpa 'foo 't 'nil)
         (eval-and-compile
           (add-to-list 'load-path ,(pred stringp)))
         (require 'foo nil 'nil))))
@@ -266,14 +266,14 @@
     (match-expansion
      (use-package foo :ensure t :load-path "foo")
      `(progn
-        (use-package-ensure-elpa 'foo 't 'nil :ensure)
+        (use-package-ensure-elpa 'foo 't 'nil)
         (eval-and-compile
           (add-to-list 'load-path ,(pred stringp)))
         (require 'foo nil 'nil))))
 
   (let (tried-to-install)
     (flet ((use-package-ensure-elpa
-            (name ensure state context &optional no-refresh)
+            (name ensure state &optional no-refresh)
             (when ensure
               (setq tried-to-install name)))
            (require (&rest ignore)))