GNU bug report logs - #66938
30.0.50 [PATCH]: Make EIEIO :accessor behave like :reader when reading a slot's value

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Brandon Irizarry <brandon.irizarry <at> gmail.com>
Subject: bug#66938: closed (Re: bug#66938: 30.0.50 [PATCH]: Make EIEIO
 :accessor behave like :reader when reading a slot's value)
Date: Sun, 26 Nov 2023 13:53:03 +0000

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Your bug report

#66938: 30.0.50 [PATCH]: Make EIEIO :accessor behave like :reader when reading a slot's value

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 66938 <at> debbugs.gnu.org.

-- 
66938: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=66938
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

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From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Brandon Irizarry <brandon.irizarry <at> gmail.com>
Cc: 66938-done <at> debbugs.gnu.org
Subject: Re: bug#66938: 30.0.50 [PATCH]: Make EIEIO :accessor behave like
 :reader when reading a slot's value
Date: Sun, 26 Nov 2023 08:52:19 -0500

> Done. The patch is included with this email.

Thanks, pushed to `master`.
Closing,


        Stefan

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From: Brandon Irizarry <brandon.irizarry <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 30.0.50 [PATCH]: Make EIEIO :accessor behave like :reader when
 reading a slot's value
Date: Sat, 4 Nov 2023 18:03:06 -0400

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Hope everyone is well.

I've included a suggested patch for 'eieio.el', which slightly
modifies the behavior of EIEIO's 'defclass'. When playing around with
'eieio-instance-inheritor' as a base class, I noticed that calls to
the accessor (when used as a getter) weren't delegating to the parent
instance (as defined when calling 'clone'). That is, an object clone that
doesn't set
its fields directly will report 'nil' when the accessor method is used as a
getter for some slot.

However, neither 'oref' nor ':reader' methods share this problem.

The included patch duplicates the code for the reader method defined for
the ':reader' case. In particular, it removes the 'slot-unboundp' check,
which appeared
to be the real culprit here. I've also deleted the FIXME comment which
asked, "Why is this
different from the :reader case?" since it no longer differs from it.

There is some more context provided (along with an example) in the
commit message included in the patch, in case it helps.

I know this isn't earth-shattering, but I couldn't help but notice the
issue;
and, at least to me, it seemed like incorrect behavior. (Otherwise, in
order to
obtain the delegation behavior for a given slot, I'd be forced to define
 ':reader' and ':writer' separately, which feels rather verbose, given we
have ':accessor'
for this exact purpose.)

- Brandon

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[0001-Make-EIEIO-accessor-behave-like-reader-when-reading.patch (text/x-patch, attachment)]

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