GNU bug report logs - #48489
28.0.50; Incorrect Edebug instrumentation for old `when-let' form

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Philipp <p.stephani2 <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 28.0.50; Incorrect Edebug instrumentation for old `when-let' form
Date: Tue, 18 May 2021 00:08:30 +0200

Insert the following form into *scratch*:

(defun f (a) (when-let (b (not a)) b))

Edebug-evaluate it using C-u M-C-x.

Now evaluate (f 1).  Edebug will not stop at the (not a) form, only the
`a' symbol.  The instrumented form is indeed incorrect:
(symbol-function 'f) gives

(closure
 (t)
 (a)
 (edebug-enter 'f
	       (list a)
	       #'(lambda nil
		   (edebug-after
		    (edebug-before 0)
		    3
		    (let*
			((b
			  (and t
			       (not
				(edebug-after 0 1 a)))))
		      (if b
			  (edebug-after 0 2 b)
			nil))))))

Note the missing edebug-before/after around the `not' form.

This can be rectified by swapping the two `&or' branches in the Edebug
specification for `if-let', which makes sense given the first branch is
often a superset of the second.  I don't mind doing that, but maybe
there are negative conseqences from that that I don't see?


In GNU Emacs 28.0.50 (build 120, aarch64-apple-darwin20.4.0, NS appkit-2022.44 Version 11.3.1 (Build 20E241))
 of 2021-05-17
Repository revision: f572735c5105a84da3175ae6cdad807fa103dfe1
Repository branch: master
Windowing system distributor 'Apple', version 10.3.2022
System Description:  macOS 11.3.1

Configured using:
 'configure --with-modules --without-xml2 --without-pop --with-mailutils
 --enable-gcc-warnings=warn-only --enable-checking=all
 --enable-check-lisp-object-type 'CFLAGS=-ggdb3 -O0''

Configured features:
ACL GNUTLS JSON LCMS2 MODULES NOTIFY KQUEUE NS PDUMPER PNG THREADS
TOOLKIT_SCROLL_BARS ZLIB

Important settings:
  value of $LANG: de_DE.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc dired dired-loaddefs rfc822
mml mml-sec epa epg epg-config gnus-util rmail rmail-loaddefs time-date
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils phst skeleton derived edmacro kmacro pcase ffap thingatpt url
url-proxy url-privacy url-expand url-methods url-history url-cookie
url-domsuf url-util url-parse auth-source cl-seq eieio eieio-core
cl-macs eieio-loaddefs password-cache json map url-vars mailcap rx
gnutls puny dbus xml subr-x seq byte-opt gv bytecomp byte-compile cconv
compile text-property-search comint ansi-color ring cl-loaddefs cl-lib
iso-transl tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/ns-win ns-win ucs-normalize mule-util
term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch easymenu
timer select scroll-bar mouse jit-lock font-lock syntax font-core
term/tty-colors frame minibuffer cl-generic cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms
cp51932 hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese composite charscript charprop case-table epa-hook
jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice button
loaddefs faces cus-face macroexp files window text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote threads kqueue cocoa ns lcms2
multi-tty make-network-process emacs)

Memory information:
((conses 16 70904 5824)
 (symbols 48 8362 1)
 (strings 32 24249 2101)
 (string-bytes 1 793015)
 (vectors 16 16050)
 (vector-slots 8 212531 11281)
 (floats 8 26 28)
 (intervals 56 219 0)
 (buffers 992 10))

Message #10 received at 48489-done <at> debbugs.gnu.org (full text, mbox):

From: Philipp Stephani <p.stephani2 <at> gmail.com>
To: 48489-done <at> debbugs.gnu.org
Subject: Re: bug#48489: 28.0.50; Incorrect Edebug instrumentation for old
 `when-let' form
Date: Tue, 18 May 2021 09:29:13 +0200

Am Di., 18. Mai 2021 um 00:09 Uhr schrieb Philipp <p.stephani2 <at> gmail.com>:
> This can be rectified by swapping the two `&or' branches in the Edebug
> specification for `if-let', which makes sense given the first branch is
> often a superset of the second.  I don't mind doing that, but maybe
> there are negative conseqences from that that I don't see?

I guess the easiest way to find out is to make the change and see
whether anything breaks ;-)
Done with commit 9676d41b8301b84e07717e633059a3f2b5c4c9d8.

Message #13 received at 48489 <at> debbugs.gnu.org (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: Philipp <p.stephani2 <at> gmail.com>
Cc: 48489 <at> debbugs.gnu.org
Subject: Re: bug#48489: 28.0.50;
 Incorrect Edebug instrumentation for old `when-let' form
Date: Tue, 18 May 2021 10:59:08 -0400

Philipp wrote:

> This can be rectified by swapping the two `&or' branches in the Edebug
> specification for `if-let', which makes sense given the first branch is
> often a superset of the second.  I don't mind doing that, but maybe
> there are negative conseqences from that that I don't see?

Since 9676d41, edebug-tests-duplicate-symbol-backtrack fails.
Ref eg https://hydra.nixos.org/build/143298928
Reproduced on CentOS 8.3.

Message #16 received at 48489 <at> debbugs.gnu.org (full text, mbox):

From: Philipp Stephani <p.stephani2 <at> gmail.com>
To: Glenn Morris <rgm <at> gnu.org>
Cc: 48489 <at> debbugs.gnu.org
Subject: Re: bug#48489: 28.0.50; Incorrect Edebug instrumentation for old
 `when-let' form
Date: Tue, 18 May 2021 17:55:57 +0200

Am Di., 18. Mai 2021 um 16:59 Uhr schrieb Glenn Morris <rgm <at> gnu.org>:
>
> Philipp wrote:
>
> > This can be rectified by swapping the two `&or' branches in the Edebug
> > specification for `if-let', which makes sense given the first branch is
> > often a superset of the second.  I don't mind doing that, but maybe
> > there are negative conseqences from that that I don't see?
>
> Since 9676d41, edebug-tests-duplicate-symbol-backtrack fails.
> Ref eg https://hydra.nixos.org/build/143298928
> Reproduced on CentOS 8.3.

Hmm, I can't reproduce this on Debian. But I don't see how this could
be OS-dependent.

Message #19 received at 48489 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Philipp Stephani <p.stephani2 <at> gmail.com>
Cc: Glenn Morris <rgm <at> gnu.org>, 48489 <at> debbugs.gnu.org
Subject: Re: bug#48489: 28.0.50; Incorrect Edebug instrumentation for old
 `when-let' form
Date: Tue, 18 May 2021 18:25:00 +0200

Philipp Stephani <p.stephani2 <at> gmail.com> writes:

> Hmm, I can't reproduce this on Debian. But I don't see how this could
> be OS-dependent.

It reproduces fine here on Debian/bullseye, at least:

1 unexpected results:
   FAILED  edebug-tests-duplicate-symbol-backtrack



-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Message #22 received at 48489 <at> debbugs.gnu.org (full text, mbox):

From: Philipp Stephani <p.stephani2 <at> gmail.com>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Glenn Morris <rgm <at> gnu.org>, 48489 <at> debbugs.gnu.org
Subject: Re: bug#48489: 28.0.50; Incorrect Edebug instrumentation for old
 `when-let' form
Date: Tue, 18 May 2021 18:27:36 +0200

Am Di., 18. Mai 2021 um 18:25 Uhr schrieb Lars Ingebrigtsen <larsi <at> gnus.org>:
>
> Philipp Stephani <p.stephani2 <at> gmail.com> writes:
>
> > Hmm, I can't reproduce this on Debian. But I don't see how this could
> > be OS-dependent.
>
> It reproduces fine here on Debian/bullseye, at least:
>
> 1 unexpected results:
>    FAILED  edebug-tests-duplicate-symbol-backtrack
>

Yeah, I can also reproduce it now. Not sure what changed in the
meantime on my system.

Message #25 received at 48489 <at> debbugs.gnu.org (full text, mbox):

From: Philipp Stephani <p.stephani2 <at> gmail.com>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Glenn Morris <rgm <at> gnu.org>, 48489 <at> debbugs.gnu.org
Subject: Re: bug#48489: 28.0.50; Incorrect Edebug instrumentation for old
 `when-let' form
Date: Tue, 18 May 2021 18:34:35 +0200

Am Di., 18. Mai 2021 um 18:27 Uhr schrieb Philipp Stephani
<p.stephani2 <at> gmail.com>:
>
> Am Di., 18. Mai 2021 um 18:25 Uhr schrieb Lars Ingebrigtsen <larsi <at> gnus.org>:
> >
> > Philipp Stephani <p.stephani2 <at> gmail.com> writes:
> >
> > > Hmm, I can't reproduce this on Debian. But I don't see how this could
> > > be OS-dependent.
> >
> > It reproduces fine here on Debian/bullseye, at least:
> >
> > 1 unexpected results:
> >    FAILED  edebug-tests-duplicate-symbol-backtrack
> >
>
> Yeah, I can also reproduce it now. Not sure what changed in the
> meantime on my system.

Ah. See the FIXME in the test:

                     ;; FIXME: There are twice as many inner
                     ;; definitions as expected due to Bug#42701.
                     ;; Once that bug is fixed, remove the duplicates.

Bug#42701 still isn't fixed, but the fix to bug#48489 has "suppressed"
its symptom in this case. We can therefore resolve this FIXME.
However, then the edebug-tests-duplicate-symbol-backtrack doesn't
really test any more what it should be testing. So I'll see that I can
change it to restore the previous behavior (which requires
backtracking and overlapping &or branches).

Message #28 received at 48489 <at> debbugs.gnu.org (full text, mbox):

From: Philipp Stephani <p.stephani2 <at> gmail.com>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Glenn Morris <rgm <at> gnu.org>, 48489 <at> debbugs.gnu.org
Subject: Re: bug#48489: 28.0.50; Incorrect Edebug instrumentation for old
 `when-let' form
Date: Tue, 18 May 2021 18:49:59 +0200

Am Di., 18. Mai 2021 um 18:34 Uhr schrieb Philipp Stephani
<p.stephani2 <at> gmail.com>:
>
> Am Di., 18. Mai 2021 um 18:27 Uhr schrieb Philipp Stephani
> <p.stephani2 <at> gmail.com>:
> >
> > Am Di., 18. Mai 2021 um 18:25 Uhr schrieb Lars Ingebrigtsen <larsi <at> gnus.org>:
> > >
> > > Philipp Stephani <p.stephani2 <at> gmail.com> writes:
> > >
> > > > Hmm, I can't reproduce this on Debian. But I don't see how this could
> > > > be OS-dependent.
> > >
> > > It reproduces fine here on Debian/bullseye, at least:
> > >
> > > 1 unexpected results:
> > >    FAILED  edebug-tests-duplicate-symbol-backtrack
> > >
> >
> > Yeah, I can also reproduce it now. Not sure what changed in the
> > meantime on my system.
>
> Ah. See the FIXME in the test:
>
>                      ;; FIXME: There are twice as many inner
>                      ;; definitions as expected due to Bug#42701.
>                      ;; Once that bug is fixed, remove the duplicates.
>
> Bug#42701 still isn't fixed, but the fix to bug#48489 has "suppressed"
> its symptom in this case. We can therefore resolve this FIXME.
> However, then the edebug-tests-duplicate-symbol-backtrack doesn't
> really test any more what it should be testing. So I'll see that I can
> change it to restore the previous behavior (which requires
> backtracking and overlapping &or branches).

Done with commit 63e4ed1c8f1c5bbf59c366134d379bae972201f9.

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