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Hey! I've stumbled upon a problem on defining custom slot initargs using metaclass and then redefining the class. Let me illustrate with an example:
(ql:quickload :closer-mop)
(defclass custom-slot (c2mop:standard-direct-slot-definition)
((custom-arg
:accessor custom-arg
:initarg :custom-arg
:initform nil)))
(defclass custom-metaclass (c2mop:standard-class) ())
(defmethod c2mop:validate-superclass ((class custom-metaclass)
(super c2mop:standard-class))
t)
(defmethod c2mop:direct-slot-definition-class ((class custom-metaclass)
&rest initargs)
(declare (ignore class initargs))
(find-class 'custom-slot))
(defmethod shared-initialize ((class custom-metaclass) slots &rest rest)
(declare (ignorable rest))
(unless (eq slots t)
(dolist (slot (c2mop:class-direct-slots class))
(format t "s-i custom-arg = ~a~%" (custom-arg slot))))
(call-next-method))
(defclass my-class ()
((my-slot
:accessor my-slot
:initform 42
:type fixnum
:custom-arg 'bar))
(:metaclass custom-metaclass))
(defclass my-class ()
((my-slot
:accessor my-slot
:initform 42
:type fixnum
:custom-arg 'buzz))
(:metaclass custom-metaclass))
(print (my-slot (make-instance 'my-class)))This example works correctly with SBCL, CCL, ECL, Allegro CL and CLISP, but fails in ABCL saying
#<THREAD "interpreter" native {2F6A2561}>: Debugger invoked on condition of type UNBOUND-SLOT
The slot CUSTOM-ARG is unbound in the object #<CUSTOM-SLOT {27D76870}>.
(this happens when SHARED-INITIALIZE is called because of class redefinition).
Does my modest knowledge of MOP fail me, or is it a bug in ABCL?
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