Strange character showing in file listing in Nautilus in some views, for Thai language file names

Screenshot 2, showing that the issue does not occur in List view.

Screen shot 3, showing the issue again in compact icon view. (Ctrl-3)

Screenshot 4: Showing that the strange character disappears when renaming a file.

After completing the renaming (hitting enter) the strange character(s) show up again.

Comment: I could also add that this bug has been there for a while, from the start of Beta 1 at least. It's not due to a recent update or system change.

Final screen shot: It also happens on the desktop, and happens for files of any type. Note that regular Latin character file names are not affected.

^ Interestingly, it only happens when the non-Latin character preceeds the dot or dash. Looking at the three icons at the top in the previous screenshot, those have some Thai language in them, but a latin character preceeds the dot. The issue does not occur.

thank you for your bug report, could you add an example of such file to the bug?

Is that issue new in precise? Do you know when it started?

I don't know when it started, but I don't recall ever seeing it in 11.10.

I attach a small text file with a name that uses Thai characters. The strange character appears after the dash and after the dot.

I tested it with some other non Western scripts (Korean and Hindi) and the issue does not occur there. It seems specific to Thai.

Note: I added the requested file a couple days ago but the status of this bug is still 'incomplete'.

Please review and let me know if I can provide additional information, if you were able to reproduce the bug (saving the attached file on the desktop should show it.) and if it can be classified as a bug, or that the status should be updated to something else.

Thanks!

Thanks, that's a bug in the code that helps wrapping labels at the right position for the icon view

nautilus-icon-canvas-item.c has this code

"
#define ZERO_WIDTH_SPACE "\xE2\x80\x8B"

  for (p = text; *p != '\0'; p++) {
   str = g_string_append_c (str, *p);

   if (*p == '_' || *p == '-' || (*p == '.' && !g_ascii_isdigit(*(p+1)))) {
    /* Ensure that we allow to break after '_' or '.' characters,
     * if they are not followed by a number */
    str = g_string_append (str, ZERO_WIDTH_SPACE);
   }
  }"

it seems like the "zero width space" is what is creating the issue, I'm unsure why that's happening though.

One bug I can see is that the code is iterating over char types, and an utf8 non ascii glyph might not fit in a char, so it could insert value in the middle of an utf8 sequence and corrupt it, but that doesn't seem to be what is happening there since the "weird" glyphs are added after "_" and "."

That code is hackish, I had to fix a bug in it recently and pondered dropped it, maybe we should do that. I confirmed that dropping it fixes the issue

I've opened https://bugzilla.gnome.org/show_bug.cgi?id=674924 upstream to discuss the issue with their

upstream said on IRC "looks like a but in the pango Thai shaper", reassigning there, the upstream bug is https://bugzilla.gnome.org/show_bug.cgi?id=677090

This bug was fixed in the package pango1.0 - 1.30.0-0ubuntu4

---------------
pango1.0 (1.30.0-0ubuntu4) quantal; urgency=low

  * debian/patches/git_thai_zero_width_spaces.patch:
    - correctly handle zero width spaces in thai (lp: #986008)
 -- Sebastien Bacher <email address hidden> Wed, 30 May 2012 18:02:05 +0200

Hello Chanchao, or anyone else affected,

Accepted pango1.0 into precise-proposed. The package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

Excellent, thank you very much! I will test at the first opportunity.

Did you have a chance to test it yet?

Sorry for the delay, I was travelling on a business trip. I just updated these packages from the Proposed-repository and it works perfectly!

Thank you very much to everyone involved in providing a speedy solution!!

Cheers,
Chanchao

This bug was fixed in the package pango1.0 - 1.30.0-0ubuntu3

---------------
pango1.0 (1.30.0-0ubuntu3) precise-proposed; urgency=low

  * debian/patches/git_thai_zero_width_spaces.patch:
    - correctly handle zero width spaces in thai (lp: #986008)
 -- Sebastien Bacher <email address hidden> Wed, 30 May 2012 18:02:05 +0200