[gentoo-dev] tagging eclasses with allowed transitive inherits

[Tim Harder]

In terms of QA, unintentional transitive eclass usage is generally bad.
This occurs when an ebuild uses functionality from an eclass it doesn't
directly inherit. It would be useful for eclasses that allow certain
transitive usage (e.g. various python eclasses) to be able to tag that
relationship internally so tools can make use of that data.

Along those lines, pkgcheck now has eclass doc parsing support which
allows scanning ebuilds for missing, indirect, or unused eclass inherits
as well as internal eclass function usage. In order to more closely
report valid indirect inherit results, some tag including this data
needs to be included for eclasses allowing this relationship.

What do interested parties think about including an optional eclass doc
tag such as '@TRANSITIVE_INHERITS:' or other similar name in eclasses
that allow this? The tag value would be a space-separated list of
allowed transitive inherits for the given eclass.

Tim