Nautilus uses magic numbers but not Gnome file chooser dialogs

[Delan Azabani]

Many of my files lack an extension for convenience; Nautilus detects the magic number inside most file formats using shared-mime-info. However, the Gnome file chooser dialogues only use extension globbing, independent from the MIME database.

[Sebastien Bacher (seb128)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please answer these questions:

 * Is this reproducible?
 * If so, what specific steps should we take to recreate this bug?
 * What ubuntu version do you use? Is the issue to render files in the list or to open something?

 This will help us to find and resolve the problem.

[Delan Azabani (azabani)]

It is reproducible. You can test this, for example, by removing the extension from a media file, and observing that it is still recognised as a media file in Nautilus because of its magic number data. Then open a media player, e.g. SMPlayer or Totem, and use the "Open..." facility. Note how the file is not listed because it doesn't match the extension glob.

As you can see, the Gnome file open dialogs use their own globbing and do not tap into the shared-mime-info database.

I'm using Lucid and the issue is that Gnome does not list files of a certain type using XML namespacing, magic numbers or the globs in the MIME database, but rather through a separate globbing mechanism.

[Sebastien Bacher (seb128)]

Thank you for your bug report. The issue is an upstream one and it would be nice if somebody having it could send the bug the to the people writting the software (https://wiki.ubuntu.com/Bugs/Upstream/GNOME)

[Sebastien Bacher (seb128)]

nautilus and gtk do use the filename to list directories because opening and reading content for every single file in the directory you browse is quite ressource expensive compared to using the filename, the detection uses the content when selecting though which is when you need to confirm the mimetype to use the correct software

[Sebastien Bacher (seb128)]

the issue might be known upstream so maybe check for bugs on bugzilla.gnome.org before opening a new one

[Delan Azabani (azabani)]

Actually, Nautilus does use the content even for listing directories, not just for the opener program. Outside of Nautilus though, most others like open dialogs, etc. all use globbing only.

[Delan Azabani (azabani)]

I'll check (and file if necessary) the bug upstream.

[Delan Azabani (azabani)]

There doesn't appear to be a bug about this reported there; reporting it now.

[Delan Azabani (azabani)]

Actually, there's a few related ones. This, for instance:

https://bugzilla.gnome.org/show_bug.cgi?id=128888

It looks like the Gnome developers chose globbing over shared MIME for everything except Nautilus because it's more user friendly - the only problem is, Gnome apps cannot be configured to use shared MIME.

[Sebastien Bacher (seb128)]

Thank you for sending the bug to GNOME

[Sebastien Bacher (seb128)]

could you give us the GNOME bug number so we can track this one too using a bug watch