xfce dependancy problem with fam vs gamin

It's not a dependency, gamin is only recommended by xfdesktop4 (at least in 11.04, but it should be the same in 10.04). So you should be able to replace it by fam if you prefer (maybe you'll need to disable the automatic installation of recommended packages by default for that to work).

While looking a bit further: xfce4 -> (depends) -> thunar -> (recommend) -> gamin (only)

Package: thunar
Section: xfce
Architecture: any
Depends: ${shlibs:Depends}, ${misc:Depends}, desktop-file-utils,
 shared-mime-info, thunar-data (= ${source:Version}), exo-utils
Recommends: hal, dbus-x11, gamin, ${shlibs:Recommends}, thunar-volman,
 xdg-user-dirs

If thunar would state gamin | fam that might solve the problem where I get:

root@localhost:~/XFCE# apt-get install xfce4
Reading package lists... Done
Building dependency tree
Reading state information... Done

The following packages will be REMOVED:
  fam libfam0
The following NEW packages will be installed:
  exo-utils gamin gtk2-engines-xfce libexo-0.3-0 libexo-common libgamin0 libthunar-vfs-1-2 libxfce4menu-0.1-0 libxfce4util-common libxfce4util4 libxfcegui4-4 libxfconf-0-2 orage thunar thunar-data thunar-volman
  xfce-keyboard-shortcuts xfce4 xfce4-appfinder xfce4-mixer xfce4-panel xfce4-session xfce4-settings xfce4-utils xfconf xfdesktop4 xfdesktop4-data xfwm4

This bug was fixed in the package xfdesktop4 - 4.8.2-1ubuntu1

---------------
xfdesktop4 (4.8.2-1ubuntu1) oneiric; urgency=low

  * Merge with Debian unstable, remaining Ubuntu changes:
    - debian/patches:
      + xubuntu_hide-ugly-resize-grip.patch: disable resize grips for xfdesktop's
        root windows. lp: #709279
      + series: added.

  * Bugs closed by this new upstream release:
    - crash with SIGSEGV in g_closure_invoke() lp: #724816
    - crash with SIGSEGV in g_type_check_instance_is_a() lp: #733822
    - explicit gamin dependency dropped lp: #776503
    - crash on exit with xorg-server 1.10 lp: #711571
    - Cannot create an empty file on the desktop lp: #754595
 -- Lionel Le Folgoc <email address hidden> Sat, 11 Jun 2011 22:39:00 +0200

Will this fix be backported for Ubuntu 10.04 LTS ?

Because this morning I still see:
The following packages have unmet dependencies:
  libthunar-vfs-1-2: Depends: libgamin0 but it is not going to be installed

I gave a try this morning into fixing the problem (with success) by changing theses:
Source: thunar
Section: xfce
Priority: optional
Maintainer: Xubuntu Developers <email address hidden>
XSBC-Original-Maintainer: Debian Xfce Maintainers <email address hidden>
Uploaders: Yves-Alexis Perez <email address hidden>, Emanuele Rocca <email address hidden>, Simon Huggins <email address hidden>
Build-Depends: debhelper (>= 7), libcairo2-dev,
 libexo-0.3-dev (>= 0.3.100), cdbs, libxml-parser-perl, libgamin-dev,

to:
 libexo-0.3-dev (>= 0.3.100), cdbs, libxml-parser-perl, libgamin-dev | libfam-dev,

and this:
Package: thunar
Section: xfce
Architecture: any
Depends: ${shlibs:Depends}, ${misc:Depends}, desktop-file-utils,
 shared-mime-info, thunar-data (= ${source:Version}), exo-utils
Recommends: hal, dbus-x11, gamin, ${shlibs:Recommends}, thunar-volman,
 xdg-user-dirs

to:
Recommends: hal, dbus-x11, gamin | fam, ${shlibs:Recommends}, thunar-volman,
 xdg-user-dirs

I can then install all the build dependancies and start a proper build using libfam-dev instead of gamin. At the end of the build the ${shlibs:Depends} of thunar gets translated to this (from file libthunar-vfs-1-2.substvars at deb creation time):
shlibs:Depends=libatk1.0-0 (>= 1.29.3), libc6 (>= 2.11), libcairo2 (>= 1.2.4), libdbus-1-3 (>= 1.0.2), libdbus-glib-1-2 (>= 0.78), libexif12, libexo-0.3-0 (>= 0.3.100), libfam0, libfontconfig1 (>= 2.8.0), libfreetype6 (>= 2.2.1), libglib2.0-0 (>= 2.23.5), libgtk2.0-0 (>= 2.10.1), libhal-storage1 (>= 0.5.8.1), libhal1 (>= 0.5.8.1), libjpeg62, libpango1.0-0 (>= 1.14.0), libpcre3 (>= 7.7), libpng12-0 (>= 1.2.13-4), libxfce4util4 (>= 4.6.0), zlib1g (>= 1:1.1.4)
misc:Depends=

Where it becomes linked to libfam0 instead of libgamin0 and declared as is in the debian package.

Now, since package libgamin0 provides an equivalent to libfam0 this should allow to use gamin OR fam with thunar...

Package: libgamin0
Section: libs
Architecture: any
Depends: ${misc:Depends},
         ${shlibs:Depends},
         gamin
Conflicts: libfam0c102, libfam0
Provides: libfam0c102, libfam0
Replaces: libfam0c102, libfam0

Package: libgamin-dev
Section: libdevel
Architecture: any
Depends: ${misc:Depends},
         ${shlibs:Depends},
         libgamin0 (= ${binary:Version})
Conflicts: libfam-dev
Provides: libfam-dev
Replaces: libfam-dev

Now the questions becomes:
1) Should fam declare that it can provide gamin? (libfam0 provides libgamin0)... Having libfam0 would then work properly what ever the dependancies are...
-- OR --
2) Should thunar be mentionning in it's build-deb that it links to libfam-dev by default? And thus use "fam | gamin" instead of the reverse so that fam becomes the default... I have a strong feeling that it will always libgamin0 anyway since most probably build on a system running gamin and not fam.
-- OR --
3) Having the deb making sure it change the automatic translation of ${shlibs:Depends} in libthunar-vfs-1-2.substvars so that i...

libthunar-vfs-1-2 is still linked to gamin libs and thus it's impossible to install xfce using fam instead of gamin. See last comment for more informations on this.

This is fixed in the current development release (with Xfce 4.8, thunar-vfs is deprecated and thnar and xfdesktop4 moved to gio), but won't be backported to the previous ones (too many changes, especially in ubuntu 10.04 which only has xfce 4.6), sorry.

That explains. thnx.