I'm not sure it is a Xft or a fontconfig bug, please reassign if needed.
Currently, when you try to get a font for an alias and the choosen font is not
readable, there is no way to resolve this alias correctly. Here is an example :
-as root, just make sure to chmod a-r on a font file which is triggered by an
alias (for instance, chmod a-r on your vera font)
-then as simple use, start an app which uses the "sans" alias (any GNOME apps)
=> app will fail to start. Moreover, it will also bypass the fallback mecanism
in pango which try to load "sans" when a font can't be found.
We probably need to check, when resolving a pattern and when the font found is
not readable, to use the second font in the pattern list.
This can be quite problematic when people are importing fonts from Windows world
with incorrect permission (see http://bugs.mandrakelinux.com/query.php?bug=177
which is also a bug in mozilla which was crashing mozilla).
Is this still an issue? Closing due to age and lack of comments. Please
reopen if it is still valid.