bug#20914: eieio/slot/group

[Pierre Lorenzon]

Sorry in fact it works when patching and recompiling the whole
stuff.Recompiling only cl-preloaded.el is not enough.

Anyway copy-tree should be used and not copy-sequence for the
properties. Otherwise properties are not eq but car of them are
eq and that's not what we want.


Pierre

From: Pierre Lorenzon <devel@pollock-nageoire.net>
Subject: bug#20914: eieio/slot/group
Date: Wed, 01 Jul 2015 06:02:28 +0200 (CEST)

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Subject: Re: bug#20914: eieio/slot/group
> Date: Tue, 30 Jun 2015 14:09:20 -0400
> 
>>> The problem comes from use of `copy-sequence' in
>>> `eieio-copy-parents-into-subclass' function of eieio-core. this
>>> copy is not reccursive as explained in code comment but it
>>> should be ! There's a joined patch that fixes the bug.
>> 
>> Thanks for the investigation.  I think the fix should be
> 
> 
>   Sure it is better to have a true copier for
>   cl--slot-descriptor.
> 
> 
>> applied deeper.  Can you confirm that the patch below works for you
> 
>   unfortunately it does not ! I modified cl-preloaded.el
>   recompiled it but once restarting emacs my example classes do
>   not havae suitable properties. When doing Ch f
>   cl--copy-slot-descriptor I get that it is an alias for
>   copy-sequence as it was before and not the function defined
>   by the new definition you gave. Moreover if I force
>   cl-prelaoded.el to be loaded I get the correct definition. I
>   suspect that things are not loaded as they should but why
>   ....
> 
> 
> 
> 
>> as well?
>> 
>> 
>>         Stefan
>> 
>> 
>> diff --git a/lisp/emacs-lisp/cl-preloaded.el 
>> b/lisp/emacs-lisp/cl-preloaded.el
>> index ed0639b..2e9bdde 100644
>> --- a/lisp/emacs-lisp/cl-preloaded.el
>> +++ b/lisp/emacs-lisp/cl-preloaded.el
>> @@ -195,7 +195,7 @@
>>                 (:constructor nil)
>>                 (:constructor cl--make-slot-descriptor
>>                  (name &optional initform type props))
>> -               (:copier cl--copy-slot-descriptor))
>> +               (:copier nil))
>>    ;; FIXME: This is actually not used yet, for circularity reasons!
>>    "Descriptor of structure slot."
>>    name                                  ;Attribute name (symbol).
>> @@ -205,6 +205,11 @@
>>    ;;  :documentation, :protection, :custom, :label, :group, :printer.
>>    (props nil :type alist))
>>  
>> +(defun cl--copy-slot-descriptor (slot)
>> +  (let ((new (copy-sequence slot)))
> 
> 
> 
>   Are you sure that a copy-sequence will be enough here ? props
>   themselves are sequences hence they will be referenced by
>   this copy-sequence not copied. I think that a copy-tree
>   should be used here.
> 
> 
>> +    (cl-callf copy-sequence (cl--slot-descriptor-props new))
>> +    new))
>> +
>>  (cl-defstruct (cl--class
>>                 (:constructor nil)
>>                 (:copier nil))
> 
>                 Ok I'll try to understand why it does not
>                 work. I'll probably learn something in this
>                 history and that's good !
> 
> 
> Pierre
> 
> 
>