[gentoo-dev] Standardise the variable for including eclasses only once

[Ulrich Mueller]

Hi all,
Several of our eclasses use a mechanism that prevents them from being
inherited more than once. Some eclasses test for a special value [1]:

   ___ECLASS_ONCE_EUTILS="recur -_+^+_- spank"

while others simply assign 1 and test for a non-empty variable [2]:

   _GIT_R3=1

The problem with the name of the former variable is that function and
variable names starting with __ (two underscores) are reserved for
package manager use [3], so the variable should be renamed. We can
take this as an occasion to standardise the variable's name and value.

Since names like _USER or _PAM look a little dangerous, I suggest
_<eclassname>_ECLASS for the variable's name.

I have no strong preference for the variable's value. Is testing for
a non-empty value sufficient? Then we should assign something simple
(like "1"). If not, any string that is sufficiently random (like the
one used in eutils) should be good.

Ulrich


[1] http://thread.gmane.org/gmane.linux.gentoo.devel/74303/focus=74305
[2] http://thread.gmane.org/gmane.linux.gentoo.devel/87922/focus=87928
[3] http://dev.gentoo.org/~ulm/pms/5/pms.html#x1-14300011.3.3.15