[armedbear-devel] Patch: call reinitialize-instance on metaclass on class redefinition

Alessio Stalla alessiostalla at gmail.com
Tue Apr 26 22:36:11 UTC 2011

On Sat, Apr 23, 2011 at 12:53 AM, Alessio Stalla
<alessiostalla at gmail.com> wrote:
> Hello,
> I found out that ABCL, when redefining a class, modifies the old class
> metaobject in-place, slot by slot. This has the implication that the
> redefinition of an instance of a custom metaclass does not update
> custom slots. Now, I didn't check on the AMOP, but I'm pretty sure the
> proper class redefinition protocol is more articulate than the one
> implemented in ABCL; still, applying the patch that you find attached
> fixes the problem of custom slots not being updated by calling
> reinitialize-instance where the old code manually updated the class
> metaobject, so it is, I think, a valid temporary solution until we
> have a full MOP. However, before committing the patch, I'd like to
> hear your opinion about it.
> The patch also includes some tabs converted to spaces, sorry for the noise.

Additionally, I also rectified the hierarchy for slot-definition and
subclasses, introducing the classes standard-slot-definition,
standard-direct-slot-definition and
standard-effective-slot-definition, as specified by the AMOP (except
for the METAOBJECT class, which is missing and should be on the CPL of
all metaobject classes). I ran the ANSI tests and got 33 failures, one
less than before (but that could be a randomized test passing, I
didn't check).
While I find it unlikely that someone has code defining custom slot
definitions that relies on the previous class hierarchy, this is a
potentially breaking change, so comments are welcome. If no one speaks
up in a few days, I will commit the patch on trunk and notify the
mailing list.


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