maybe i wasn't been clear. i installed gnome-python-desktop and meld doesn't detect that i installed that. is complaining that "Line numbers are only available if you have gnome-python-desktop installed." when i check show line numbers

Package "gtksourceview" is required for meld to show it. It will still complain that it misses "gnome-python-desktop" even it is installed.

gnome-python-desktop need to be rebuild.
maibe a new report ?

i installed gtksourceview and meld doesn't complain that gnome-python-desktop isn't installed.
i think gtksourceview is a dependency for gnome-python-desktop or for meld

/usr/lib/python2.5/site-packages/gtk-2.0/gtksourceview.so needs missing libgnomeprint-2-2.so.0 libgtksourceview-1.0.so.0
/usr/lib/python2.5/site-packages/gtk-2.0/gtksourceview.so -> gnome-python-desktop

gnome-python-desktop needs a "recommend=('gtksourceview')" ;-)

From what I understood after googling a bit:

gnome-python-desktop is a library of python modules interfacing various gnome components.
those components include metacity, gtksourceview, etc.
now those python components are linked against (or they use) the various libraries
of the GNOME desktop.
so technically, gnome-python-desktop should depend on all these things so that any application which calls gnome-python-desktop is assured that it can use the underlying libraries properly.
meld uses the gtksourceview component of the gnome-python-desktop.

Problems:
Since Arch does not package libraries and binaries separately (for the most part), adding
a depends on metacity gtksourceview etc.. will pull in loads of dependencies which might irritate users.

One way out is to add a depends=('gtksourceview') to meld so that meld will properly
work. gnome-python-desktop cannot possibly have all those dependencies... so best way
out IMO is to manually specify the underlying GNOME component(s) of gnome-python-desktop
which the application uses.

Hmm, that is an interesting problem :P
So indeed, meld requires BOTH gnome-python-desktop and gtksourceview for syntax highlighting and line number to work.
If one is missing, it will complain that gnome-python-desktop is not installed.
However, these two features are optional, meld is still functional without them.

So I would suggest using the following deps for meld :
depends=('gnome-python')
optdepends=('gnome-python-desktop:syntax highlighting' 'gtksourceview:syntax highlighting')

Also, I think all the optional deps for gnome-python-desktop should be listed in its optdepends. According to namcap, they are :
gnome-media
gnome-panel
nautilus-cd-burner
totem-plparser
libgtop
gtksourceview

That'll be depends=('gnome-python-desktop') :)

I didn't know about optdepends. Does
pacman have the ability to print out or do anything with the
optdepends (like a switch to install them?)

No, it was not a mistake, I did mean depends=('gnome-python').
gnome-python-desktop is not required for meld to work, it is optional.

About optdepends, currently they are only printed on -Si / -Qi operation.
They should probably be printed out on installation, this needs to be discussed in more details.
A switch to install them is lower priority, but it would be interesting to discuss it too.
Do you mind opening a feature request on pacman for a better optdepends support, to discuss both of your proposals?

Done! http://bugs.archlinux.org/task/10630

please check if it is solved in meld-1.2-1

you can close it. is working