bug#49043: 27.1: ibuffer-toggle-filter-group [BUGFIX]

[Stephen Berman <stephen.berman@gmx.net>]

On Wed, 16 Jun 2021 10:19:23 +0200 Lars Ingebrigtsen <larsi@gnus.org> wrote:

> Boruch Baum <boruch_baum@gmx.com> writes:
>
>> Oops. I misquoted the code (because I had submitted the report after I
>> had made/tested/byte-compiled/over-writte my only local copy). If you look at the
>> code on the gnu cgit instance, at line 1907, you'll see that it adds one
>> to the line-end-position before passing the value the function
>> delete-region.
>
> Right -- so I guess the problem here is that the last line of the buffer
> doesn't have a newline...  but skimming the code (I'm not super-familiar
> with ibuffer), it seems like the final non-newline line is a summary
> line and should be kept out of the sorting/filtering process?  (If
> there's a "buffer line" without a newline, it'll mess up the display
> after filtering.)
>
> So I think that perhaps the bug is somewhere else, but it's hard to say
> without a recipe that reproduces the bug.
>
> Do you have a test case?

I do.  It's the result of an error being raised in Tramp.  Here's the
recipe (reliably reproducible on

GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.29,
cairo version 1.17.4) of 2021-06-06 built on strobelfs 
Repository revision: 218d2d1509673d8bc67014558a31f5d0da1be5c6
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
Configured using: 'configure --with-native-compilation 'CFLAGS=-Og -g3''
Configured features: ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS
GSETTINGS HARFBUZZ JPEG LCMS2 LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP
NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF
TOOLKIT_SCROLL_BARS X11 XDBE XIM XPM GTK3 ZLIB
):

0. emacs -Q
1. Create a nonempty ZIP file test.zip (content is irrelevant).
2. Visit the directory containing test.zip in Dired.
3. Type `M-x load-library RET dired-x RET'.
4. With point on the Dired line containing test.zip type `M-!', which
   prompts with "! on test.zip {3 guesses} [unzip]:" and type RET to
   execute unzip (this of course requires having the unzip program).
5. With point still on the test.zip line type `D' and at the prompt `y'
   to delete the ZIP file.
=> This raises a file-error (see below), but the ZIP file is deleted.
6. Type `M-x ibuffer'.
=> This raises the error "tramp-error: Method ‘archive’ is not known."
7. In the *Ibuffer* buffer type `g'.
=> This raises the error "ibuffer-current-state-list: Args out of range:
   #<buffer *Ibuffer*>, 280, 332". 

The latter error is apparently what the OP reported, and it's because
the Ibuffer buffer is corrupted; here's what it looks like after step 7,
except for the last character `|', which I added to show EOB:

[ Default ]
  %  tmp                      802 Dired by name    /tmp/
 *%  *Messages*               754 Messages         
  %  steve                   4171 Dired by name    ~/
     *scratch*                145 Lisp Interaction 
 *   *Shell Command ...       114 Fundamental      
     *tramp/archive ...         0 Fundamental      |

In other words, as you deduced, the summary line is missing, so the
attempt to do delete-region errors out.

The corruption of the Ibuffer buffer is due to the error raised at step
6, which is triggered in ibuffer-redisplay-engine during the execution
of ibuffer-insert-filter-group.  This errors prevent the subsequent
execution of ibuffer-update-title-and-summary, resulting in the above
corrupted Ibuffer display.

As for the error at step 5, which is the cause of the following errors,
it is raised in tramp-gvfs-maybe-open-connection.  Here's what the
*Messages* buffer contains after step 5:

Deleting... 
Waiting for git... [2 times]
Tramp: Opening connection for file%3A%2F%2F%2Ftmp%2Ftest.zip using archive...failed
file-error: org.gtk.GDBus.UnmappedGError.Quark._g_2dio_2derror_2dquark.Code1 Error when getting information for file “/tmp/test.zip”: No such file or directory

Step 3 of the recipe is necessary to raise the above errors.  I guess
dired-guess-shell-command triggers Tramp file handling.  CCing Michael
Albinus, who should be able to solve the problem.

Steve Berman