scratch/pkg 22d0b7dccd5 1/2: Handle case of unspecified use-list

[Gerd Moellmann]

branch: scratch/pkg
commit 22d0b7dccd5d774583825938e385d327600e85a5
Author: Gerd Möllmann <gerd@gnu.org>
Commit: Gerd Möllmann <gerd@gnu.org>

    Handle case of unspecified use-list
    
    * lisp/emacs-lisp/pkg.el (make-package): Allow null size.
    (pkg-defpackage): Check for :use eq :default = no change.
---
 lisp/emacs-lisp/pkg.el | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/lisp/emacs-lisp/pkg.el b/lisp/emacs-lisp/pkg.el
index 64076ef3695..4fbb0eb895d 100644
--- a/lisp/emacs-lisp/pkg.el
+++ b/lisp/emacs-lisp/pkg.el
@@ -291,7 +291,7 @@ registered in the package registry, that is it will not be 
found
 under its names by `find-package'.  Use `register-package' to
 register the package.  This deviates from the CLHS specification,
 but is what Common Lisp implementations usually do."
-  (cl-check-type size natnum)
+  (cl-check-type size (or null natnum))
   (let* ((name (pkg--stringify-name name "package name"))
          (nicknames (pkg--stringify-names nicknames "package nickname"))
          (use (pkg--packages-from-names use))
@@ -600,14 +600,15 @@ Value is t."
              name old-shadows)))
 
     ;;Use
-    (let ((old-use-list (package-use-list package))
-         (new-use-list (mapcar #'pkg--package-or-lose use)))
-      (use-package (cl-set-difference new-use-list old-use-list) package)
-      (let ((laterize (cl-set-difference old-use-list new-use-list)))
-       (when laterize
-         (unuse-package laterize package)
+    (unless (eq use :default)
+      (let ((old-use-list (package-use-list package))
+           (new-use-list (mapcar #'pkg--package-or-lose use)))
+        (use-package (cl-set-difference new-use-list old-use-list) package)
+        (let ((laterize (cl-set-difference old-use-list new-use-list)))
+         (when laterize
+           (unuse-package laterize package)
            (warn "%s previously used the following packages: %s"
-                 name laterize))))
+                 name laterize)))))
 
     ;;Import and Intern.
     (dolist (sym-name interns)
@@ -628,8 +629,8 @@ Value is t."
        (when diff
          (warn "%s also exports the following symbols: %s" name diff))))
 
-    ;; Documentation
-    ;(setf (package-doc-string package) doc-string)
+    ;; Documentation (not yet)
+    ;;(setf (package-doc-string package) doc-string)
     package))
 
 (defmacro defpackage (package &rest options)