Bug 471658

Summary:	[Future EAPI] A way to declare 'soft' dependencies of USE flags (unlike REQUIRED_USE)
Product:	Gentoo Hosted Projects	Reporter:	Michał Górny <mgorny>
Component:	PMS/EAPI	Assignee:	PMS/EAPI <pms>
Status:	RESOLVED OBSOLETE
Severity:	enhancement	CC:	esigra, pacho, python
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
See Also:	https://bugs.gentoo.org/show_bug.cgi?id=424283
Whiteboard:
Package list:		Runtime testing required:	---
Bug Depends on:
Bug Blocks:	174380

Description Michał Górny archtester

2013-05-29 06:56:22 UTC

REQUIRED_USE supports only declaring 'hard' dependencies of two USE flags -- that is, 'foo? ( bar )' makes PM fail if USE='-bar foo' and require him to adjust the flags. This is mostly expected but there are cases when the enforcing flags are set in the profile.

For example, if a package that has an optional dep on Python stated:

  REQUIRED_USE="!python? ( !python_targets_... )"

to express that PYTHON_TARGETS are meaningless without USE=python, PM would require user to unset all Python targets on the package which is not really helpful.

What I would see is a 'soft' counterpart to REQUIRED_USE. For example:

  MEANINGFUL_USE="!python ( !python_targets_... )"

would solely 'gray out' PYTHON_TARGETS and avoid rebuilding the package on PYTHON_TARGETS change when USE=-python is used.

Comment 1 Michał Górny archtester

2014-09-06 15:35:51 UTC

Runtime USE flags can serve as 'good enough' replacement.

Comment 2 Michał Górny archtester

2017-02-14 12:34:19 UTC

I'm going to roll out a more complete proposal for this.