bug#394: wdired-change-to-wdired-mode can cause file deletion

bug#394: wdired-change-to-wdired-mode can cause file deletion

[xah lee]

In dired, do M-x wdired-change-to-wdired-mode.

Then, swap 2 files's names.

Emacs will ask if the first file should be overwritten. If answer  
yes, it'll be deleted, and it wont be renamed. i.e. you lose a file.

This can be reproduced if you created 2 files, one named A and other  
B. Then renamed them to B and A. (Possibly you will need to create 3  
files and rename in particular cycle depending on how emacs choose  
the order to rename... The key is to get emacs to prompte for the  
overwrite of a file that should be renamed to something else later.)

This behavior is slightly unexpected and caused me to retrieve from  
my backup disk. (the files are images and never edited, so it isn't  
in emacs's backup)

   Xah
∑ http://xahlee.org/

☄

bug#394: marked as done (wdired-change-to-wdired-mode can cause file deletion)

[Emacs bug Tracking System]

[-- Attachment #1: Type: text/plain, Size: 893 bytes --]


Your message dated Sat, 14 Jun 2008 13:01:52 -0400
with message-id <jwv63scdk9t.fsf-monnier+emacsbugreports@gnu.org>
and subject line Re: bug#394: wdired-change-to-wdired-mode can cause file deletion
has caused the Emacs bug report #394,
regarding wdired-change-to-wdired-mode can cause file deletion
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact don@donarmstrong.com
immediately.)


-- 
394: http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=394
Emacs Bug Tracking System
Contact don@donarmstrong.com with problems

[-- Attachment #2: Type: message/rfc822, Size: 2869 bytes --]

From: xah lee <xah@xahlee.org>
To: bug-gnu-emacs@gnu.org
Subject: wdired-change-to-wdired-mode can cause file deletion
Date: Thu, 12 Jun 2008 01:39:07 -0700
Message-ID: <E6D43431-8B39-457D-9965-99D36FA41303@xahlee.org>

In dired, do M-x wdired-change-to-wdired-mode.

Then, swap 2 files's names.

Emacs will ask if the first file should be overwritten. If answer  
yes, it'll be deleted, and it wont be renamed. i.e. you lose a file.

This can be reproduced if you created 2 files, one named A and other  
B. Then renamed them to B and A. (Possibly you will need to create 3  
files and rename in particular cycle depending on how emacs choose  
the order to rename... The key is to get emacs to prompte for the  
overwrite of a file that should be renamed to something else later.)

This behavior is slightly unexpected and caused me to retrieve from  
my backup disk. (the files are images and never edited, so it isn't  
in emacs's backup)

   Xah
∑ http://xahlee.org/

☄





[-- Attachment #3: Type: message/rfc822, Size: 2266 bytes --]

From: Stefan Monnier <monnier@iro.umontreal.ca>
To: 394-done@emacsbugs.donarmstrong.com
Subject: Re: bug#394: wdired-change-to-wdired-mode can cause file deletion
Date: Sat, 14 Jun 2008 13:01:52 -0400
Message-ID: <jwv63scdk9t.fsf-monnier+emacsbugreports@gnu.org>

> In dired, do M-x wdired-change-to-wdired-mode.
> Then, swap 2 files's names.
> Emacs will ask if the first file should be overwritten. If answer yes, it'll
> be deleted, and it wont be renamed. i.e. you lose a file.

Indeed, dired's rename is a "parallel" rename, whereas our underlying
C primitives only offer sequential renaming, so we need to de more work
to handle those cases.

I've installed a patch into the CVS trunk which should fix it (or at
least catch the problem before it's too late).


        Stefan