[XeTeX] Polyglossia "broken"?

[Heiko Oberdiek]

On Wed, Sep 21, 2011 at 10:21:46PM +1000, VAFA KHALIGHI wrote:

> > It is a bug in polyglossia that xkeyval has to be loaded manually
> > before polyglossia, because polyglossia has
> > forgotten \RequirePackage{xkeyval}.
> >
> >
> >
> Not really. fontspec used to load xkeyval and polyglossia loaded fontspec so
> there was no need for polyglossia to load xkeyval again.

No, packages *MUST* add packages for *all* required packages.
The use of xkeyval for fontspec was an *implementation* detail
that can change *any* time, like it has now happened.
AFAIK, the use of xkeyval was never part of the official interface
for fontspec. This would not make any sense, because fontspec deals
with fonts and is not a package for providing key value parsers.

Therefore it is a very clear bug of polyglossia, not to load
xkeyval. A package can be loaded many times using \usepackage
or \RequirePackage. LaTeX only loads the package at the first
request. At the later requests it only checks the date and options
of the request.

It is also good style to add a date, if a package must not be too old:
  \RequirePackage{foo}[2010/04/20]
Then LaTeX will complain, if the loaded packages is too old.

Yours sincerely
  Heiko Oberdiek