Re: eieio-base patch to support EDE project loading

[Stefan Monnier]

> Without that list of superclasses, `child-of-class-p' fails.  Since having
> the superclass list in autoloads is a non-starter, this patch will
> un-autoload classes found in the file being read before the call to
> `child-of-class-p'.

Looks good, but I felt like those un-autoloads scattered around felt
a bit haphazard (with tests slightly different each time), so I suggest
the patch below instead, WDYT (which also moves the un-autoload to
child-of-class-p so it applies not just to
eieio-persistent-validate/fix-slot-value but to all users of
child-of-class-p).

> It would be better to store the superclasses in the autoload declaration so
> that extensible class hierarchies can be more dynamically loaded without
> internal checks with un-autoload, but I don't know enough about how the new
> version of eieio works to provide that patch.

It would allow child-of-class-p to be computed without loading the
class, hence a bit more laziness, but I'm wondering how often it would
make a real difference: how likely are you to use child-of-class-p
without either already having an instance of that class or being right
about to build such an instance?

Can you test the patch below before I push it?


        Stefan


diff --git a/lisp/emacs-lisp/eieio-base.el b/lisp/emacs-lisp/eieio-base.el
index 534613811d..fc78b3e098 100644
--- a/lisp/emacs-lisp/eieio-base.el
+++ b/lisp/emacs-lisp/eieio-base.el
@@ -277,8 +277,7 @@ eieio-persistent-convert-list-to-object
          (progn
            ;; If OBJCLASS is an eieio autoload object, then we need to
            ;; load it.
-           (eieio-class-un-autoload objclass)
-           (eieio--class-object objclass))))
+           (eieio--full-class-object objclass))))
 
     (while slots
       (let ((initarg (car slots))
diff --git a/lisp/emacs-lisp/eieio-core.el b/lisp/emacs-lisp/eieio-core.el
index 620b47e68d..3d5d4765f1 100644
--- a/lisp/emacs-lisp/eieio-core.el
+++ b/lisp/emacs-lisp/eieio-core.el
@@ -125,7 +125,8 @@ eieio--object-class-tag
 (defsubst eieio--class-object (class)
   "Return the class object."
   (if (symbolp class)
-      ;; Keep the symbol if class-v is nil, for better error messages.
+      ;; Keep the symbol if the class object doesn't exist,
+      ;; for better error messages.
       (or (cl--find-class class) class)
     class))
 
@@ -217,10 +218,6 @@ eieio-defclass-autoload
         (make-obsolete-variable cname (format "use \\='%s instead" cname)
                                 "25.1"))
 
-      ;; Store the new class vector definition into the symbol.  We need to
-      ;; do this first so that we can call defmethod for the accessor.
-      ;; The vector will be updated by the following while loop and will not
-      ;; need to be stored a second time.
       (setf (cl--find-class cname) newc)
 
       ;; Create an autoload on top of our constructor function.
@@ -230,9 +227,17 @@ eieio-defclass-autoload
         (autoload (intern (format "%s-child-p" cname)) filename "" nil nil)
         (autoload (intern (format "%s-list-p" cname)) filename "" nil nil)))))
 
-(defsubst eieio-class-un-autoload (cname)
-  "If class CNAME is in an autoload state, load its file."
-  (autoload-do-load (symbol-function cname))) ; cname
+(defun eieio--full-class-object (class)
+  "Like `eieio--class-object' but loads the class if needed."
+  (let ((c (eieio--class-object class)))
+    (and (not (symbolp c))
+         ;; If the default-object-cache slot is nil, the class object
+         ;; is still a "dummy" setup by eieio-defclass-autoload.
+         (not (eieio--class-default-object-cache c))
+         ;; FIXME: We rely on the autoload setup for the "standard"
+         ;; constructor, here!
+         (autoload-do-load (symbol-function (eieio--class-name c))))
+    c))
 
 (cl-deftype list-of (elem-type)
   `(and list
@@ -730,9 +735,7 @@ eieio-oref
   (cl-check-type obj (or eieio-object class))
   (let* ((class (cond ((symbolp obj)
                        (error "eieio-oref called on a class: %s" obj)
-                       (let ((c (cl--find-class obj)))
-                         (if (eieio--class-p c) (eieio-class-un-autoload obj))
-                         c))
+                       (eieio--full-class-object obj))
                       (t (eieio--object-class obj))))
         (c (eieio--slot-name-index class slot)))
     (if (not c)
@@ -1013,16 +1016,15 @@ eieio--class-precedence-list
 method invocation orders of the involved classes."
   (if (or (null class) (eq class eieio-default-superclass))
       nil
-    (unless (eieio--class-default-object-cache class)
-      (eieio-class-un-autoload (eieio--class-name class)))
-    (cl-case (eieio--class-method-invocation-order class)
-      (:depth-first
-       (eieio--class-precedence-dfs class))
-      (:breadth-first
-       (eieio--class-precedence-bfs class))
-      (:c3
-       (eieio--class-precedence-c3 class))))
-  )
+    (let ((class (eieio--full-class-object class)))
+      (cl-case (eieio--class-method-invocation-order class)
+        (:depth-first
+         (eieio--class-precedence-dfs class))
+        (:breadth-first
+         (eieio--class-precedence-bfs class))
+        (:c3
+         (eieio--class-precedence-c3 class))))))
+
 (define-obsolete-function-alias
   'class-precedence-list 'eieio--class-precedence-list "24.4")
 
diff --git a/lisp/emacs-lisp/eieio.el b/lisp/emacs-lisp/eieio.el
index 4b899cdc64..103c02f795 100644
--- a/lisp/emacs-lisp/eieio.el
+++ b/lisp/emacs-lisp/eieio.el
@@ -468,7 +468,7 @@ 'obj-of-class-p
 
 (defun child-of-class-p (child class)
   "Return non-nil if CHILD class is a subclass of CLASS."
-  (setq child (eieio--class-object child))
+  (setq child (eieio--full-class-object child))
   (cl-check-type child eieio--class)
   ;; `eieio-default-superclass' is never mentioned in eieio--class-parents,
   ;; so we have to special case it here.