GNU bug report logs - #8174
24.0.50; `replace-match' doesn't work right with propertized text

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

From: "Drew Adams" <drew.adams <at> oracle.com>
To: <bug-gnu-emacs <at> gnu.org>
Subject: 24.0.50; `replace-match' doesn't work right with propertized text
Date: Fri, 4 Mar 2011 14:16:06 -0800

C-x C-f foo.txt
 
Type this text (between the lines) into buffer foo.txt:
 
--------------------------------
toto
titi
tata
tutu
tete
 

(defun foo ()
  (interactive)
  (require 'image-dired)
  (save-excursion
    (goto-char (point-min))
    (re-search-forward "tata")
    (let* ((file  "@@@@@")
    (strg  (apply #'propertize "AAAAAA"
    `(display ,(image-dired-get-thumbnail-image file)
       rear-nonsticky (display)))))
      (replace-match strg))))
--------------------------------
 
Replace `@@@@@' in `foo's definition by a real image-file absolute file
name, and then evaluate the definition.  Then `M-x foo RET'.
 
I would expect the text `tata' to be replaced by the propertized string,
whose text is `AAAAAAA' and whose properties are as indicated.  IOW, I
would expect to see the image displayed in place of `tata'.
 
Instead, the image is displayed at a different location: in place of the
"ursi" in `save-excursion'.
 
If you put the cursor at the beginning of the displayed image (just
after the `c' of `save-excursion') and hit `C-u C-x =', you'll see
something like this in *Help*, with the image appearing after
`character: ' in *Help* (i.e. in place of `A'):
 
        character: A (65, #o101, #x41)
preferred charset: ascii (ASCII (ISO646 IRV))
       code point: 0x41
           syntax: w  which means: word
         category: .:Base, a:ASCII, l:Latin, r:Roman
      buffer code: #x41
        file code: #x41 (encoded by coding system iso-latin-1-dos)
          display: by this font (glyph code)
    uniscribe:-outline-Courier
New-normal-normal-normal-mono-13-*-*-*-c-*-iso8859-1 (#x24)
 
Character code properties: customize what to show
  name: LATIN CAPITAL LETTER A
  general-category: Lu (Letter, Uppercase)
 
There are text properties here:
  display              [Show]
  fontified            t
  rear-nonsticky       (display)
 
[back]
 
If you click the `Show' button for property `display' then you see,
correctly, the image spec for the thumbnail image - e.g.,
(image :type jpeg
:file "c:/.emacs.d/image-dired/abc_33e34a7116fe5da6ff6a9103c8774f02.thumb.jpg")
 
Similarly for each of the `A's that replaced `ursi'.  IOW, each
character `A' of the replacement has the proper `display' property.  But
the the image position is incorrect.  The wrong text seems to have been
replaced by `replace-match'.
 

In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
 of 2011-02-28 on 3249CTO
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.4) --no-opt --cflags
-Ic:/imagesupport/include'
 

Message #8 received at 8174 <at> debbugs.gnu.org (full text, mbox):

From: "Drew Adams" <drew.adams <at> oracle.com>
To: <8174 <at> debbugs.gnu.org>
Subject: RE: bug#8174: 24.0.50;
	`replace-match' doesn't work right with propertized text
Date: Fri, 4 Mar 2011 14:42:13 -0800

Some additional info:

In Emacs 22.3, the same thing happens.  But in that case, the image is put at
yet a different position.  Instead of replacing the `ursi' in `save-excursion',
it replaces the `to\nt' of `toto\ntiti'.  The displayed result is this:

to|---------------|iti

where |---------------| is location of the displayed image.


Seems like a longstanding bug, but it manifests itself a bit differently now.

Message #11 received at 8174 <at> debbugs.gnu.org (full text, mbox):

From: "Drew Adams" <drew.adams <at> oracle.com>
To: <8174 <at> debbugs.gnu.org>
Subject: RE: bug#8174: 24.0.50;
	`replace-match' doesn't work right with propertized text
Date: Fri, 4 Mar 2011 16:01:46 -0800

Besides a fix for this bug, I would like to know about any workarounds that
might be usable in releases where the bug is not yet fixed.  Thx.

Message #14 received at 8174 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: "Drew Adams" <drew.adams <at> oracle.com>
Cc: 8174 <at> debbugs.gnu.org
Subject: Re: bug#8174: 24.0.50;
	`replace-match' doesn't work right with propertized text
Date: Fri, 04 Mar 2011 23:18:10 -0500

> (defun foo ()
>   (interactive)
>   (require 'image-dired)
>   (save-excursion
>     (goto-char (point-min))
>     (re-search-forward "tata")
>     (let* ((file  "@@@@@")
>     (strg  (apply #'propertize "AAAAAA"
>     `(display ,(image-dired-get-thumbnail-image file)
>        rear-nonsticky (display)))))
>       (replace-match strg))))
> --------------------------------
 
> Replace `@@@@@' in `foo's definition by a real image-file absolute file
> name, and then evaluate the definition.  Then `M-x foo RET'.
 
> I would expect the text `tata' to be replaced by the propertized string,
> whose text is `AAAAAAA' and whose properties are as indicated.  IOW, I
> would expect to see the image displayed in place of `tata'.

First things first: (ignoring the lack of check that re-search-forward
indeed succeeded) the only things allowed between the string match and
the use of the match-data are a few Emacs primitives known to leave the
match-data untouched.  image-dired-get-thumbnail-image is not one of
those primitives.


        Stefan

Message #17 received at 8174 <at> debbugs.gnu.org (full text, mbox):

From: "Drew Adams" <drew.adams <at> oracle.com>
To: "'Stefan Monnier'" <monnier <at> iro.umontreal.ca>
Cc: 8174 <at> debbugs.gnu.org
Subject: RE: bug#8174: 24.0.50;
	`replace-match' doesn't work right with propertized text
Date: Fri, 4 Mar 2011 21:05:32 -0800

> >     (re-search-forward "tata")
> >     (let* ((file  "@@@@@")
> >     (strg  (apply #'propertize "AAAAAA"
> >     `(display ,(image-dired-get-thumbnail-image file)
> >        rear-nonsticky (display)))))
> >       (replace-match strg))))
>  
> First things first: (ignoring the lack of check that
> re-search-forward indeed succeeded)

The real code uses (when (re-search-forward... nil t)...).

> the only things allowed between the string match and
> the use of the match-data are a few Emacs primitives known to 
> leave the match-data untouched.  image-dired-get-thumbnail-image
> is not one of those primitives.

Yes, that's the problem here, so no bug.  I was not expecting to need to wrap
the `(apply... )' in `save-match-data'.  Usually I can pretty much tell when the
match data gets modified, but I guess I should have looked closer at
`image-dired-get-thumbnail-image'.

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