Re: package.el dependencies

[Thierry Volpiatto]

I will not have a good connection until next week, so I am unable to
push a branch, so I am just attaching patch of all my changes against
package.el here.

diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 88fc950..df3a108 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -333,6 +333,15 @@ contents of the archive."
   :group 'package
   :version "24.4")
 
+(defcustom packages-installed-directly nil
+  "Store here packages installed explicitely by user.
+This variable will be feeded automaticaly by emacs,
+so you should not modify it yourself.
+This variable will be used by `package-autoremove' to decide
+which packages are no more needed."
+  :group 'package
+  :type '(repeat (choice symbol)))
+
 (defvar package--default-summary "No description available.")
 
 (cl-defstruct (package-desc
@@ -1187,7 +1196,7 @@ using `package-compute-transaction'."
   (mapc #'package-install-from-archive packages))
 
 ;;;###autoload
-(defun package-install (pkg)
+(defun package-install (pkg &optional arg)
   "Install the package PKG.
 PKG can be a package-desc or the package name of one the available packages
 in an archive in `package-archives'.  Interactively, prompt for its name."
@@ -1206,7 +1215,11 @@ in an archive in `package-archives'.  Interactively, 
prompt for its name."
                                     (unless (package-installed-p (car elt))
                                       (symbol-name (car elt))))
                                   package-archive-contents))
-                    nil t)))))
+                    nil t))
+           "\p")))
+  (when (and arg (not (memq pkg packages-installed-directly)))
+    (customize-save-variable 'packages-installed-directly
+                            (cons pkg packages-installed-directly)))
   (package-download-transaction
    (if (package-desc-p pkg)
        (package-compute-transaction (list pkg)
@@ -1388,26 +1401,105 @@ The file can either be a tar file or an Emacs Lisp 
file."
       (when (string-match "\\.tar\\'" file) (tar-mode)))
     (package-install-from-buffer)))
 
-(defun package-delete (pkg-desc)
-  (let ((dir (package-desc-dir pkg-desc)))
-    (if (not (string-prefix-p (file-name-as-directory
-                               (expand-file-name package-user-dir))
-                              (expand-file-name dir)))
-        ;; Don't delete "system" packages.
-       (error "Package `%s' is a system package, not deleting"
-               (package-desc-full-name pkg-desc))
-      (delete-directory dir t t)
-      ;; Remove NAME-VERSION.signed file.
-      (let ((signed-file (concat dir ".signed")))
-       (if (file-exists-p signed-file)
-           (delete-file signed-file)))
-      ;; Update package-alist.
-      (let* ((name (package-desc-name pkg-desc))
-             (pkgs (assq name package-alist)))
-        (delete pkg-desc pkgs)
-        (unless (cdr pkgs)
-          (setq package-alist (delq pkgs package-alist))))
-      (message "Package `%s' deleted." (package-desc-full-name pkg-desc)))))
+(defun package--get-deps (pkg &optional only)
+  (let* ((pkg-desc (cadr (assq pkg package-alist)))
+         (direct-deps (cl-loop for p in (package-desc-reqs pkg-desc)
+                               for name = (car p)
+                               when (assq name package-alist)
+                               collect name))
+         (indirect-deps (unless (eq only 'direct)
+                          (cl-loop for p in direct-deps
+                                   for dep = (cadr (assq p package-alist))
+                                   when (and dep (assq p package-alist))
+                                   append (mapcar 'car
+                                                  (package-desc-reqs
+                                                   dep))))))
+    (cl-case only
+      (direct   direct-deps)
+      (separate (list direct-deps indirect-deps))
+      (indirect indirect-deps)
+      (t        (append direct-deps indirect-deps)))))
+
+(defun package-used-elsewhere-p (pkg &optional pkg-list)
+  "Check in PKG-LIST if PKG is used elsewhere as dependency.
+When not specified, PKG-LIST default to `package-alist' with PKG entry removed.
+Argument PKG is a symbol.
+Returns the first package found in PKG-LIST where PKG is used as dependency."
+  (cl-loop with alist = (or pkg-list
+                            (remove (assq pkg package-alist)
+                                    package-alist))
+           for p in alist thereis
+           (and (memq pkg (mapcar 'car (package-desc-reqs (cadr p))))
+                (car p))))
+
+(defun package-delete (pkg-desc &optional force)
+  "Delete package PKG-DESC.
+
+Argument PKG-DESC is a full description of package as vector.
+When package is used elsewhere as dependency of another package,
+refuse deleting it and return an error.
+If FORCE is non--nil package will be deleted even if it is used
+elsewhere."
+  (let ((dir (package-desc-dir pkg-desc))
+        (name (package-desc-name pkg-desc))
+        pkg-used-elsewhere-by)
+    (cond ((not (string-prefix-p (file-name-as-directory
+                                  (expand-file-name package-user-dir))
+                                 (expand-file-name dir)))
+           ;; Don't delete "system" packages.
+           (error "Package `%s' is a system package, not deleting"
+                  (package-desc-full-name pkg-desc)))
+          ((and (null force)
+                (setq pkg-used-elsewhere-by
+                      (package-used-elsewhere-p name)))
+           ;; Don't delete packages used as dependency elsewhere.
+           (error "Package `%s' is used by `%s' as dependency, not deleting"
+                  (package-desc-full-name pkg-desc)
+                  pkg-used-elsewhere-by))
+          (t 
+           (delete-directory dir t t)
+           ;; Remove NAME-VERSION.signed file.
+           (let ((signed-file (concat dir ".signed")))
+             (if (file-exists-p signed-file)
+                 (delete-file signed-file)))
+           ;; Update package-alist.
+           (let ((pkgs (assq name package-alist)))
+             (delete pkg-desc pkgs)
+             (unless (cdr pkgs)
+               (setq package-alist (delq pkgs package-alist))))
+           (message "Package `%s' deleted." (package-desc-full-name 
pkg-desc))))))
+
+;;;###autoload
+(defun package-autoremove ()
+  "Remove packages that are no more needed.
+
+Packages that are no more needed by other packages in
+`packages-installed-directly' and their dependencies
+will be deleted."
+  (interactive)
+  (let* (old-direct
+         (needed (cl-loop for p in packages-installed-directly
+                          if (assq p package-alist)
+                          append (package--get-deps p) into lst
+                          else do (push p old-direct)
+                          finally return lst)))
+    (cl-loop for p in (mapcar 'car package-alist)
+             unless (or (memq p needed)
+                        (memq p packages-installed-directly))
+             collect p into lst
+             finally (if lst
+                         (when (y-or-n-p (format "%s packages will be 
deleted:\n%s, proceed? "
+                                                 (length lst)
+                                                 (mapconcat 'symbol-name lst 
", ")))
+                           (mapc (lambda (p)
+                                   (package-delete (cadr (assq p 
package-alist)) t))
+                                 lst)
+                           (customize-save-variable
+                            'packages-installed-directly
+                            (cl-loop for p in packages-installed-directly
+                                     unless (memq p old-direct)
+                                     collect p)))
+                       (message "Nothing to autoremove")))))
 
 (defun package-archive-base (desc)
   "Return the archive containing the package NAME."
@@ -2178,7 +2270,7 @@ Optional argument NOQUERY non-nil means do not ask the 
user to confirm."
                       (length install-list)
                       (mapconcat #'package-desc-full-name
                                  install-list ", ")))))
-         (mapc 'package-install install-list)))
+         (mapc (lambda (p) (package-install p 1)) install-list)))
     ;; Delete packages, prompting if necessary.
     (when delete-list
       (if (or


-- 
Thierry
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