reinitialize-instance on class metaobjects incorrect

[rschlatte]

Reported by Pascal Costanza:

Consider the following test case:

CL-USER(1): (use-package :mop)
T
CL-USER(2): (defclass a () ())
#<STANDARD-CLASS A {794563AA}>
CL-USER(3): (defclass b (a) ())
#<STANDARD-CLASS B {62F6FB59}>
CL-USER(4): (finalize-inheritance (find-class 'a))
NIL
CL-USER(5): (finalize-inheritance (find-class 'b))
NIL
CL-USER(6): (class-precedence-list (find-class 'b))
(#<STANDARD-CLASS B {62F6FB59}> #<STANDARD-CLASS A {794563AA}> #<STANDARD-CLASS STANDARD-OBJECT {23309E87}> #<BUILT-IN-CLASS T {100C62C8}>)
CL-USER(7): (reinitialize-instance (find-class 'b))
#<STANDARD-CLASS B {62F6FB59}>
CL-USER(8): (class-precedence-list (find-class 'b))
(#<STANDARD-CLASS B {62F6FB59}> #<STANDARD-CLASS STANDARD-OBJECT {23309E87}> #<BUILT-IN-CLASS T {100C62C8}>)

The invocation of reinitialize-instance obviously reinitialized the direct-superclasses slot, and thus removed the superclass a.

However, according to the HyperSpec?, the general protocol for reinitialize-instance is always that slots for which no initargs are provided through reinitialize-instance should be left untouched. This also restated implicitly in the CLOS MOP specification, for example in the section "Initialization of Class Metaobjects:" The defaulted superclass list is specified to be only assigned during initialization, but not during reinitialization.

[rschlatte]

(In [14293]) Don't clobber class objects when re-initializing.

• Also remove double-initialization via shared-initialize + one of intialize-instance / reinitialize-instance.

• Fixes #277

• Reported by Pascal Costanza

[Mark Evenson]

(In [14294]) Backport r14293: Don't clobber class objects when re-initializing.

• Also remove double-initialization via shared-initialize + one of

intialize-instance / reinitialize-instance.

• Fixes #277

• Reported by Pascal Costanza