[comps.xml] groupreq and metapkg

[Alain TAUCH <anaconda maisondubonheur com>]

hello

I thought:
- groupreq was used to include a group in the "mandatory" way.
- metapkg was a kind of groupreq but with the packagereq tag behaviour
  ==> could be choosen or not during the installation process.

but I found in comps.py:
-----8<--------------------------------------------------------
  if node.name == 'groupreq':
    type = node.prop ('type')
    if not type:
      type = u'mandatory'
    if type != 'mandatory' and type != 'default' and type != 'optional':
      raise CompsException
    group = totext (node.content)
    self.groups[group] = (type, group)
  elif node.name == 'metapkg':
    type = node.prop ('type')
    if not type:
      type = u'default'
    if type != 'default' and type != 'optional':
      raise CompsException
    group = totext (node.content)
    self.metapkgs[group] = (type, group)
-----8<---------------------------------------------------------

this means:
- a type option could be specified for the groupreq tag,
  accepting "mandatory", "optional" and "default" values
- the metapkg type could only be "default" or "optional"

what I don't understand:
- what does <groupreq type="optional"> do ?
  (different behaviour than <metapkg type="optional")
- same for the "default" type.

-- 
Alain