STRINGIFY a class doesn't work with LispWorks 8.0.1

[louis77]

I have a call like this:

(stringify (make-instance 'ping-response :message "pong"))

Class definition:

(defclass ping-response ()
  ((message
    :initarg :message
    :type string)))

I'm getting the error message:

Call to ERROR {offset 152}
  SYSTEM::ESTRING : CONDITIONS::SLOT-MISSING-ERROR
  SYSTEM::EARGS   : (:NAME #<STANDARD-EFFECTIVE-SLOT-DEFINITION OB.API::MESSAGE 82205E0C6B> :INSTANCE #<OB.API::PING-RESPONSE 80100B6223> :CLASS #<STANDARD-CLASS OB.API::PING-RESPONSE 82204D905B> :OPERATION SLOT-BOUNDP :NEW-VALUE NIL)

Call to CLOS::SLOT-BOUNDP-MISSING {offset 188}
  CLOS::WRAPPER   : #(2367 (OB.API::MESSAGE) NIL #<STANDARD-CLASS OB.API::PING-RESPONSE 82204D905B> (#<STANDARD-EFFECTIVE-SLOT-DEFINITION OB.API::MESSAGE 82205E0C6B>) 1)
  CLOS::OBJECT    : #<OB.API::PING-RESPONSE 80100B6223>
  CLOS::SLOT-NAME : #<STANDARD-EFFECTIVE-SLOT-DEFINITION OB.API::MESSAGE 82205E0C6B>

Backtrace:

Call to INVOKE-DEBUGGER
Call to ERROR
Call to CLOS::SLOT-BOUNDP-MISSING
Call to REMOVE-IF-NOT
Call to (METHOD COM.INUOE.JZON:COERCED-FIELDS (STANDARD-OBJECT))
Call to (METHOD COM.INUOE.JZON:WRITE-VALUE (COM.INUOE.JZON:WRITER T))
Call to CLOS::NEXT-METHOD-CALL-2
Call to (METHOD COM.INUOE.JZON:WRITE-VALUE :AROUND (COM.INUOE.JZON:WRITER T))
Call to (HARLEQUIN-COMMON-LISP:SUBFUNCTION (FLET COM.INUOE.JZON::STRINGIFY-TO) STRINGIFY)
Call to STRINGIFY
Call to EVAL
Call to CAPI::CAPI-TOP-LEVEL-FUNCTION
Call to CAPI::INTERACTIVE-PANE-TOP-LOOP
Call to MP::PROCESS-SG-FUNCTION

The corresponding code is in https://github.com/Zulu-Inuoe/jzon/blob/d6428d6602752d44d5b08e9c0a51d31f92aee2ab/src/jzon.lisp#L1134C1-L1135C70 , however I couldn't figure out the reason.

[louis77]

I did a little more research, but I'm not sure if I'm on the right track.

In CLOSER-MOP, there is this definition:

(cl:defmethod slot-boundp-using-class
           ((class standard-class) object (slotd standard-effective-slot-definition))
  (declare (optimize (speed 3) (debug 0) (safety 0)
                     (compilation-speed 0)))
  (slot-boundp-using-class
   (load-time-value (class-prototype (find-class 'cl:standard-class)))
   object
   (slot-definition-name slotd)))

in closer-lispworks.lisp.

When I change the lambda list to

(cl:defmethod slot-boundp-using-class
           ((class cl:standard-class) object (slotd standard-effective-slot-definition))

(adding the cl: package to the class specializer) the error is gone.

See https://github.com/pcostanza/closer-mop/blob/04f2d48b741ffd8c2be343e562cc49d46cce2063/closer-lispworks.lisp#L204.

The issue could be related to this: pcostanza/closer-mop#18.

[Zulu-Inuoe]

I read through that thread briefly, and it might be related. But what I find odd is that if you look at all the neighboring methods, they all follow the same exact pattern. The idea is that they specialize the slot-definition related methods to call the symbol ones.
Structurally (to me) they seem identical, so it seems odd that slot-boundp-using-class would be broken and all the others working fine.. Unless they are not

[louis77]

I've opened an issue in the CLOSER-MOP project:
pcostanza/closer-mop#22

since this seems to be unrelated to JZON itself.