aspcud solver: (minor) issue with default criteria?

[erikmd]

A question that arose after a small code review

Shouldn't this line

opam/src/solver/opamCudfSolver.ml

Line 143 in eaa702a

-count[avoid-version:,true],\

be replaced with
-sum(solution,avoid-version),\
?

because the former one seems to be mccs-specific.

And likewise, -count[missing-depexts:,true]"; → -sum(solution,missing-depexts).

Details

module Aspcud_def = struct

opam/src/solver/opamCudfSolver.ml

Lines 127 to 151 in eaa702a

	let default_criteria =
	{
	crit_default = "-count(removed),\
	-sum(solution,avoid-version),\
	-sum(request,version-lag),\
	-count(down),\
	-sum(solution,version-lag),\
	-count(changed),\
	-sum(solution,missing-depexts)";
	crit_upgrade = "-count(down),\
	-count(removed),\
	-sum(solution,avoid-version),\
	-sum(solution,version-lag),\
	-sum(solution,missing-depexts),\
	-count(new)";
	crit_fixup = "-count(changed),\
	-count[avoid-version:,true],\
	-notuptodate(solution),\
	-sum(solution,version-lag),\
	-count[missing-depexts:,true]";
	crit_best_effort_prefix = Some "+sum(solution,opam-query),";
	}
	end
	module Aspcud = External(Aspcud_def)

module Mccs_def = struct

opam/src/solver/opamCudfSolver.ml

Lines 180 to 201 in eaa702a

	let default_criteria = {
	crit_default = "-removed,\
	-count[avoid-version:,true],\
	-count[version-lag:,true],\
	-changed,\
	-count[version-lag:,false],\
	-count[missing-depexts:,true],\
	-new";
	crit_upgrade = "-removed,\
	-count[avoid-version:,true],\
	-count[version-lag:,false],\
	-count[missing-depexts:,true],\
	-new";
	crit_fixup = "-changed,\
	-count[avoid-version:,true],\
	-count[version-lag:,false],\
	-count[missing-depexts:,true]";
	crit_best_effort_prefix = Some "+count[opam-query:,false],";
	}
	end
	module Mccs = External(Mccs_def)

Off-topic context

I noticed this after experiencing timeouts with the default solver (reproducible with opam install irmin-git in some 4.12.1 switch), and diving into opam's /src/solver/ code.

Fortunately, aspcud does work, and makes it possible to obtain a solution in ~20s (unlike builtin-mccs+glpk).

# opam config report
# opam-version         2.1.5 
# self-upgrade         no
# system               arch=x86_64 os=linux os-distribution=debian os-version=11
# solver               builtin-mccs+glpk
# install-criteria     -removed,-count[avoid-version,changed],-count[version-lag,request],-count[version-lag,changed],-count[missing-depexts,changed],-changed
# upgrade-criteria     -removed,-count[avoid-version,changed],-count[version-lag,solution],-count[missing-depexts,changed],-new
# jobs                 7
# repositories         3 (http) (default repo at 45615409)
# pinned               0
# current-switch       /home/erik/forge/git/learn-ocaml
# ocaml:native         true
# ocaml:native-tools   true
# ocaml:native-dynlink true
# ocaml:stubsdir       /home/erik/forge/git/learn-ocaml/_opam/lib/ocaml/stublibs:/home/erik/forge/git/learn-ocaml/_opam/lib/ocaml
# ocaml:preinstalled   false
# ocaml:compiler       4.12.1

[kit-ty-kate]

Thanks for the report, the aspcud solver backend is an old piece of code stemming from opam 1.2 that isn't used anymore so I'm guessing nobody really noticed it. It indeed doesn't look right so feel free to open a PR to change this if you want.

#5510 should fix your original issue with mccs though.