#479: CLOS MOP bug in 1.8.0 -------------------------------+-------------------- Reporter: Mark Evenson | Type: defect Status: new | Priority: major Milestone: 1.8.1 | Component: (A)MOP Version: 1.8.1-dev | Keywords: Parent Tickets: | -------------------------------+-------------------- Pascal Costanza reports in <https://mailman.common-lisp.net/pipermail /armedbear-devel/2020-November/004189.html>:

{{{ I have encountered a bug in 1.8.0 when doing my regular Closer to MOP checks. This must be a new bug, because 1.7.1 was fine. Here is the case that triggers the problem:

(use-package :mop)

(defclass test-direct-slot-definition (standard-direct-slot-definition) ())

(defclass test-effective-slot-definition (standard-effective-slot-definition) ())

(defclass test-class (standard-class) ())

(defmethod validate-superclass ((class test-class) (superclass standard-class)) t)

(defmethod direct-slot-definition-class ((class test-class) &rest initargs) (declare (ignore initargs)) (find-class 'test-direct-slot-definition))

(defmethod effective-slot-definition-class ((class test-class) &rest initargs) (declare (ignore initargs)) (find-class 'test-effective-slot-definition))

(defclass test-object () ((some-slot :accessor some-slot :initarg :some-slot :initform 'some-slot :type symbol :allocation :class :documentation "a slot")) (:metaclass test-class))

(unless (class-finalized-p (find-class 'test-object)) (finalize-inheritance (find-class 'test-object)))

Armed Bear Common Lisp 1.8.0 Java 15.0.1 Oracle Corporation Java HotSpot(TM) 64-Bit Server VM Low-level initialization completed in 0.134 seconds. Startup completed in 0.65 seconds. Loading /Users/costanza/.abclrc completed in 6.061 seconds. Type ":help" for a list of available commands. CL-USER(1): (load "test.lisp") Error loading /Users/costanza/Temp/test.lisp at line 36 (offset 943) #<THREAD "interpreter" {1970D65C}>: Debugger invoked on condition of type UNBOUND-SLOT The slot LOCATION is unbound in the object #<TEST-EFFECTIVE-SLOT- DEFINITION {556F331F}>. Restarts: 0: TOP-LEVEL Return to top level. [1] CL-USER(2): :bt

0: (SYSTEM:BACKTRACE) 1: (INVOKE-DEBUGGER #<UNBOUND-SLOT {67D22A29}>) 2: (ERROR UNBOUND-SLOT :INSTANCE #<TEST-EFFECTIVE-SLOT-DEFINITION {556F331F}> :NAME SYSTEM::LOCATION) 3: (#<FUNCTION #<FUNCTION {22446549}> {22446549}> (#<STANDARD-CLASS TEST-EFFECTIVE-SLOT-DEFINITION {6670307A}> #<TEST-EFFECTIVE-SLOT-DEFINITION {556F331F}> SYSTEM::LOCATION)) 4: (SLOT-VALUE #<TEST-EFFECTIVE-SLOT-DEFINITION {556F331F}> SYSTEM::LOCATION) 5: (SLOT-DEFINITION-LOCATION #<TEST-EFFECTIVE-SLOT-DEFINITION {556F331F}>) 6: (MOP::STD-FINALIZE-INHERITANCE #<TEST-CLASS TEST-OBJECT {67510DAF}>) 7: (#<FUNCTION #<FUNCTION {2C5408FE}> {2C5408FE}> (#<TEST-CLASS TEST-OBJECT {67510DAF}>))

I believe the bug is triggered by find-class or class-finalized-p, but not sure. }}}