[gentoo-pms] IUSE_EFFECTIVE and IUSE_REFERENCEABLE

[Ulrich Mueller]

The spec says:

| IUSE_REFERENCEABLE
|     is a variable calculated from IUSE and a variety of other sources
|     described below. It is purely a conceptual variable; it is not
|     exported to the ebuild environment. Values in IUSE_REFERENCEABLE
|     may legally be used in queries from other packages about an
|     ebuild’s state (for example, for use dependencies).
| IUSE_EFFECTIVE
|     is another conceptual, unexported variable. Values in IUSE_
|     EFFECTIVE are those which an ebuild may legally use in queries
|     about itself (for example, for the use function, and for use in
|     dependency specification conditional blocks).
|
| [...]
|
| For EAPIs listed in table 5.2 as not supporting profile defined IUSE
| injection, IUSE_REFERENCEABLE is equal to the calculated IUSE value.
| For EAPIs where profile defined IUSE injection is supported,
| IUSE_REFERENCEABLE is equal to IUSE_EFFECTIVE.
|
| For EAPIs listed in table 5.2 as not supporting profile defined IUSE
| injection, IUSE_EFFECTIVE contains the following values:
|    * All values in the calculated IUSE value.
|    * All possible values for the ARCH variable.
|    * All legal use flag names whose name starts with the lowercase
|      equivalent of any value in the profile USE_EXPAND variable
|      followed by an underscore.

What we see for the current multilib issue is that for USE_EXPAND
flags, (+) or (-) USE dependency defaults match ebuilds in EAPI 4 and
earlier that don't have the flag in their IUSE.

So the package manager behaves as if IUSE_EFFECTIVE (but not
IUSE_REFERENCEABLE) was used for dependency matching.

Must the spec be corrected, such that it says that IUSE_REFERENCEABLE
is equal to IUSE_EFFECTIVE, for all EAPIs?

Ulrich