GNU bug report logs - #45973
replace-regexp lisp replacement bug

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 45973 in the body.
You can then email your comments to 45973 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

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

From: Nicholas Drozd <nicholasdrozd <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: replace-regexp lisp replacement bug
Date: Mon, 18 Jan 2021 18:15:09 -0600

Here is a string representing a Turing machine program:

  1RB 1LC 1RC 1RB 1RD 0LE 1LA 1LD 1RH 0LA

Say I have a file full of lines like this, and I want to swap all the
Ls for Rs and vice versa. `replace-regexp` is a good way to do it. For
the regexp, I use `\(\(L\)\|\(R\)\)`, a matching group with two nested
matching alternatives; for the replacement, I use a Lisp expression:
`\,(if \2 "R" "L")`. This expression says: if the second match is
found (the `L`), replace it with "R", else replace it with "L".

In Emacs 27 (b58fd1eab9), this gives the expected result:

  1LB 1RC 1LC 1LB 1LD 0RE 1RA 1RD 1LH 0RA

But in Emacs 28 (20add1cd22), it gives an error:

  replace-highlight: Wrong type argument: integer-or-marker-p, nil

A simpler replacement does work: `\(L\)\|R` and `\,(if \1 "R" "L")`.
But the longer one should work too.

I tried to make a Lisp test to reproduce this, but the `\,`
replacement feature is interactive-only, and I don't know how to test
it non-interactively.

Message #8 received at 45973 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Nicholas Drozd <nicholasdrozd <at> gmail.com>
Cc: 45973 <at> debbugs.gnu.org
Subject: Re: bug#45973: replace-regexp lisp replacement bug
Date: Tue, 19 Jan 2021 04:44:52 +0100

Nicholas Drozd <nicholasdrozd <at> gmail.com> writes:

> I tried to make a Lisp test to reproduce this, but the `\,`
> replacement feature is interactive-only, and I don't know how to test
> it non-interactively.

The reproducer is:

(replace-regexp "\\(\\(L\\)\\|\\(R\\)\\)" '(replace-eval-replacement replace-quote (if (match-string 2) "R" "L")) nil nil nil nil nil)

And this leads to the following backtrace:

Debugger entered--Lisp error: (wrong-type-argument integer-or-marker-p nil)
  make-overlay(nil nil)
  replace-highlight(2 3 nil nil "\\(\\(L\\)\\|\\(R\\)\\)" t nil nil nil)
  perform-replace("\\(\\(L\\)\\|\\(R\\)\\)" (replace-eval-replacement replace-quote (if (match-string 2) "R" "L")) nil t nil nil nil nil nil nil nil)
  replace-regexp("\\(\\(L\\)\\|\\(R\\)\\)" (replace-eval-replacement replace-quote (if (match-string 2) "R" "L")) nil nil nil nil nil)
  eval((replace-regexp "\\(\\(L\\)\\|\\(R\\)\\)" '(replace-eval-replacement replace-quote (if (match-string 2) "R" "L")) nil nil nil nil nil) t)
  eval-expression((replace-regexp "\\(\\(L\\)\\|\\(R\\)\\)" '(replace-eval-replacement replace-quote (if (match-string 2) "R" "L")) nil nil nil nil nil) nil nil 127)
  funcall-interactively(eval-expression (replace-regexp "\\(\\(L\\)\\|\\(R\\)\\)" '(replace-eval-replacement replace-quote (if (match-string 2) "R" "L")) nil nil nil nil nil) nil nil 127)
  call-interactively(eval-expression nil nil)
  command-execute(eval-expression)

So this is a problem with the new code that highlights the matches, I
think?

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

Message #13 received at 45973 <at> debbugs.gnu.org (full text, mbox):

From: Juri Linkov <juri <at> linkov.net>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Nicholas Drozd <nicholasdrozd <at> gmail.com>, 45973 <at> debbugs.gnu.org
Subject: Re: bug#45973: replace-regexp lisp replacement bug
Date: Tue, 19 Jan 2021 20:14:58 +0200

tags 45973 fixed
close 45973 28.0.50
thanks

> Nicholas Drozd <nicholasdrozd <at> gmail.com> writes:
>> I tried to make a Lisp test to reproduce this, but the `\,`
>> replacement feature is interactive-only, and I don't know how to test
>> it non-interactively.

Thanks for the reproducible test case.

> The reproducer is:
>
> (replace-regexp "\\(\\(L\\)\\|\\(R\\)\\)" '(replace-eval-replacement replace-quote (if (match-string 2) "R" "L")) nil nil nil nil nil)
>
> So this is a problem with the new code that highlights the matches, I
> think?

Yep.  Now fixed on master.

Message #20 received at 45973 <at> debbugs.gnu.org (full text, mbox):

From: Nicholas Drozd <nicholasdrozd <at> gmail.com>
To: Juri Linkov <juri <at> linkov.net>
Cc: Lars Ingebrigtsen <larsi <at> gnus.org>, 45973 <at> debbugs.gnu.org
Subject: Re: bug#45973: replace-regexp lisp replacement bug
Date: Tue, 19 Jan 2021 16:36:20 -0600

[Message part 1 (text/plain, inline)]

Thanks for the quick turnaround. I've included a patch to add a test for this.

[0001-test-lisp-replace-tests.el-Add-nested-match-group-te.patch (text/x-patch, attachment)]

Message #23 received at 45973 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Nicholas Drozd <nicholasdrozd <at> gmail.com>
Cc: 45973 <at> debbugs.gnu.org, Juri Linkov <juri <at> linkov.net>
Subject: Re: bug#45973: replace-regexp lisp replacement bug
Date: Wed, 20 Jan 2021 02:46:37 +0100

Nicholas Drozd <nicholasdrozd <at> gmail.com> writes:

> Thanks for the quick turnaround. I've included a patch to add a test for this.

Thanks; added to Emacs 28.

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

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.