dep_check: use DNF to optimize overlapping virtual || deps (bug 632026)
Deps like these:
|| ( foo bar ) || ( bar baz )
Translate to disjunctive normal form (DNF):
|| ( ( foo bar ) ( foo baz ) ( bar bar ) ( bar baz ) )
Using DNF, if none of the packages are currently installed,
then the ( bar bar ) choice will be automatically preferred
since it is satisfied by the fewest number of packages.
If the ( foo baz ) choice is already satisfied, then that
choice will be preferred instead.
Since DNF results in exponential explosion of the formula,
only use DNF for the parts of the dependencies that have
overlapping atoms.
In order to simplify the implementation of the dnf_convert
function, this patch also fixes _expand_new_virtuals to
normalize results in the same way as use_reduce (with no
redundant nested lists).
Bug: https://bugs.gentoo.org/632026
Reviewed-by: Manuel Rüger <mrueg@gentoo.org>
Reviewed-by: Alec Warner <antarus@gentoo.org>
5 files changed
