This is the summary of some problems and suggested new features in EAPI="4", which would solve
these problems.

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Problem #1: USE flags cannot contain "." characters.

The following solutions have been suggested:
- Add support for "." characters in USE flags in EAPI="4".

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Problem #2: Files in profiles cannot use features from newer EAPIs.

The following solutions have been suggested:
- Add support for files with "-${EAPI}" extension in EAPI="4". These files would use EAPI
  specified in their filenames instead of EAPI of profile.
  Example files:
    package.mask-${EAPI}
    package.use-${EAPI}
    package.provided-${EAPI}
    use.force-${EAPI}
    use.mask-${EAPI}
    package.use.force-${EAPI}
    package.use.mask-${EAPI}
    packages-${EAPI}
    virtuals-${EAPI}
- Create new profiles using EAPI="4", remove all older profiles from profiles.desc so that
  repoman doesn't check older profiles, and deprecate older profiles.

Council should choose one of these solutions.

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Problem #3: repoman doesn't allow stable packages to have optional dependencies on unstable
packages (usually until these packages are stabilized).

Example of the problem:
If "python_abis_2.7", "python_abis_3.1" and "python_abis_3.2" USE flags are masked using
use.mask on given architectures until Python 2.7, 3.1 and 3.2 are stabilized on these
architectures, then majority of reverse dependencies of Python won't be tested with new
versions of Python.

The following solutions have been suggested:
- Add support for use.unsatisfiable and package.use.unsatisfiable files in profiles in
  EAPI="4". These files would cause that repoman would allow optional dependencies on
  packages potentially unsatisfiable in some configurations (e.g. on stable-only systems).
- Create separate profiles for stable and unstable keywords. USE flags would be masked in
  stable profiles and unmasked in unstable profiles.

Council should choose one of these solutions.

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There are already existing patches for Portage, which implement these solutions, which are
suggested new features in EAPI="4".

-- 
Arfrever Frehtes Taifersar Arahesis