Re: [gentoo-dev] [RFC] Forced/automatic USE flag constraints (codename: ENFORCED_USE)

[Alexis Ballier]

On Sun, 4 Jun 2017 10:59:38 +0200
Alexis Ballier <aballier@g.o> wrote:

> Here's a quick n dirty code to play with, based on yours:
> https://github.com/aballier/required-use

I've run that on the whole tree (considering all ebuilds with non
empty REQUIRED_USE), some stats:

$ time python3 classify.py requsel 
Stats:
	Parse error: 16
	Good: 8316
	Need topo sort: 140
	Cyclic: 57

real	0m2.996s
user	0m2.950s
sys	0m0.004s


Running time is good I think.
Parse error is some nested construct not supported by your parser that
I have not fixed either.


~2.5% simply need to be reordered. ~0.6% require more clever thinking.


Let's have a look at a few of them:

sys-fs/cryptsetup-1.7.5
^^ ( gcrypt kernel nettle openssl ) python? ( ||
( python_targets_python2_7 python_targets_python3_4
python_targets_python3_5 python_targets_python3_6 ) )
static? ( !gcrypt )

USE='-* static' is painful: the first ^^ will enable gcrypt, static?
( !gcrypt ) will disable it. Reordering the ^^ so that kernel appears
first fixes the cycle.


media-libs/mesa-13.0.6
|| ( gcrypt libressl nettle openssl ) d3d9?
( dri3 gallium ) llvm? ( gallium ) opencl? ( gallium llvm ) openmax?
( gallium ) gles1? ( egl ) gles2? ( egl ) vaapi? ( gallium ) vdpau?
( gallium ) vulkan? ( video_cards_i965 ) wayland? ( egl gbm ) xa?
( gallium ) video_cards_freedreno? ( gallium ) video_cards_intel?
( classic ) video_cards_i915? ( || ( classic gallium ) )
video_cards_i965? ( classic ) video_cards_nouveau? ( || ( classic
gallium ) ) video_cards_radeon? ( || ( classic gallium ) gallium?
( x86? ( llvm ) amd64? ( llvm ) ) ) video_cards_r100? ( classic )
video_cards_r200? ( classic ) video_cards_r300? ( gallium x86? ( llvm )
amd64? ( llvm ) ) video_cards_r600? ( gallium ) video_cards_radeonsi?
( gallium llvm ) video_cards_vmware? ( gallium )

The cycle is mostly due to:
$ python3 nsolve.py 'llvm? ( gallium ) gallium? ( llvm )'
[...]
toposort.CircularDependencyError: Circular dependencies exist among
these items: {[gallium]? => [llvm]:{[llvm]? => [gallium]}, [llvm]? =>
[gallium]:{[gallium]? => [llvm]}}


This is something I had overseen when replacing 'a q'_j is some p_i and
one of q_1 ... q_m might be false' by only 'a q'_j is some p_i'; it can
be replaced without changing anything in the way PM would solve it by
"a q'_j is some p_i and the set of {q_j} is not a subset of q' union
p'" (that is, {q_i} is not trivially true if the 2nd clause is
applied). Extending that, we get those stats:

Stats:
	Parse error: 16
	Good: 8325
	Need topo sort: 146
	Cyclic: 42

real	0m1.575s
user	0m1.563s
sys	0m0.012s


Now we seem to get only valid warnings (I have not checked them all
though):

sys-firmware/seabios-1.10.1:
debug? ( !binary ) !amd64? ( !x86? ( binary ) )

USE="debug -amd64 -x86" ?


sci-libs/ceres-solver-1.11.0:
test? ( gflags ) sparse? ( lapack ) abi_x86_32? ( !sparse !lapack )

USE='-* sparse -lapack abi_x86_32' shows a conflict between the last 2
clauses. Better write:

test? ( gflags ) !abi_x86_32? ( sparse? ( lapack ) ) abi_x86_32?
( !sparse !lapack )

which makes the test work



mail-mta/exim-4.89
dane? ( !gnutls ) dmarc? ( spf dkim ) pkcs11? ( gnutls ) spf?
( exiscan-acl ) srs? ( exiscan-acl )

USE="dane pkcs11" ?

sci-libs/hdf5-1.8.18:
threads? ( !cxx !mpi !fortran !hl ) fortran2003? ( fortran )

USE="threads fortran2003" ?





I'll let you play with it, but for me it seems this would work quite
nicely.


Alexis.