Count conflicts to speed up solver

cabal-install/Distribution/Client/Config.hs

@@ -239,6 +239,7 @@ instance Semigroup SavedConfig where
         installDryRun                = combine installDryRun,
         installMaxBackjumps          = combine installMaxBackjumps,
         installReorderGoals          = combine installReorderGoals,
+        installCountConflicts        = combine installCountConflicts,
         installIndependentGoals      = combine installIndependentGoals,
         installShadowPkgs            = combine installShadowPkgs,
         installStrongFlags           = combine installStrongFlags,

cabal-install/Distribution/Client/Dependency.hs

@@ -48,6 +48,7 @@ module Distribution.Client.Dependency (
     addPreferences,
     setPreferenceDefault,
     setReorderGoals,
+    setCountConflicts,
     setIndependentGoals,
     setAvoidReinstalls,
     setShadowPkgs,
@@ -159,6 +160,7 @@ data DepResolverParams = DepResolverParams {
        depResolverInstalledPkgIndex :: InstalledPackageIndex,
        depResolverSourcePkgIndex    :: PackageIndex.PackageIndex UnresolvedSourcePackage,
        depResolverReorderGoals      :: ReorderGoals,
+       depResolverCountConflicts    :: CountConflicts,
        depResolverIndependentGoals  :: IndependentGoals,
        depResolverAvoidReinstalls   :: AvoidReinstalls,
        depResolverShadowPkgs        :: ShadowPkgs,
@@ -181,6 +183,7 @@ showDepResolverParams p =
        (depResolverPreferences p)
   ++ "\nstrategy: "          ++ show (depResolverPreferenceDefault p)
   ++ "\nreorder goals: "     ++ show (depResolverReorderGoals      p)
+  ++ "\ncount conflicts: "   ++ show (depResolverCountConflicts    p)
   ++ "\nindependent goals: " ++ show (depResolverIndependentGoals  p)
   ++ "\navoid reinstalls: "  ++ show (depResolverAvoidReinstalls   p)
   ++ "\nshadow packages: "   ++ show (depResolverShadowPkgs        p)
@@ -234,6 +237,7 @@ basicDepResolverParams installedPkgIndex sourcePkgIndex =
        depResolverInstalledPkgIndex = installedPkgIndex,
        depResolverSourcePkgIndex    = sourcePkgIndex,
        depResolverReorderGoals      = ReorderGoals False,
+       depResolverCountConflicts    = CountConflicts True,
        depResolverIndependentGoals  = IndependentGoals False,
        depResolverAvoidReinstalls   = AvoidReinstalls False,
        depResolverShadowPkgs        = ShadowPkgs False,
@@ -279,6 +283,12 @@ setReorderGoals reorder params =
       depResolverReorderGoals = reorder
     }
 
+setCountConflicts :: CountConflicts -> DepResolverParams -> DepResolverParams
+setCountConflicts count params =
+    params {
+      depResolverCountConflicts = count
+    }
+
 setIndependentGoals :: IndependentGoals -> DepResolverParams -> DepResolverParams
 setIndependentGoals indep params =
     params {
@@ -621,7 +631,8 @@ resolveDependencies platform comp pkgConfigDB solver params =
 
     Step (showDepResolverParams finalparams)
   $ fmap (validateSolverResult platform comp indGoals)
-  $ runSolver solver (SolverConfig reorderGoals indGoals noReinstalls
+  $ runSolver solver (SolverConfig reordGoals cntConflicts
+                      indGoals noReinstalls
                       shadowing strFlags maxBkjumps enableBj order)
                      platform comp installedPkgIndex sourcePkgIndex
                      pkgConfigDB preferences constraints targets
@@ -632,7 +643,8 @@ resolveDependencies platform comp pkgConfigDB solver params =
       prefs defpref
       installedPkgIndex
       sourcePkgIndex
-      reorderGoals
+      reordGoals
+      cntConflicts
       indGoals
       noReinstalls
       shadowing
@@ -873,7 +885,7 @@ resolveWithoutDependencies :: DepResolverParams
                            -> Either [ResolveNoDepsError] [UnresolvedSourcePackage]
 resolveWithoutDependencies (DepResolverParams targets constraints
                               prefs defpref installedPkgIndex sourcePkgIndex
-                              _reorderGoals _indGoals _avoidReinstalls
+                              _reorderGoals _countConflicts _indGoals _avoidReinstalls
                               _shadowing _strFlags _maxBjumps _enableBj _order) =
     collectEithers (map selectPackage targets)
   where

cabal-install/Distribution/Client/Fetch.hs

@@ -158,6 +158,8 @@ planPackages verbosity comp platform fetchFlags
 
       . setReorderGoals reorderGoals
 
+      . setCountConflicts countConflicts
+
       . setShadowPkgs shadowPkgs
 
       . setStrongFlags strongFlags
@@ -174,6 +176,7 @@ planPackages verbosity comp platform fetchFlags
     logMsg message rest = debug verbosity message >> rest
 
     reorderGoals     = fromFlag (fetchReorderGoals     fetchFlags)
+    countConflicts   = fromFlag (fetchCountConflicts   fetchFlags)
     independentGoals = fromFlag (fetchIndependentGoals fetchFlags)
     shadowPkgs       = fromFlag (fetchShadowPkgs       fetchFlags)
     strongFlags      = fromFlag (fetchStrongFlags      fetchFlags)

cabal-install/Distribution/Client/Freeze.hs

@@ -179,6 +179,8 @@ planPackages verbosity comp platform mSandboxPkgInfo freezeFlags
 
       . setReorderGoals reorderGoals
 
+      . setCountConflicts countConflicts
+
       . setShadowPkgs shadowPkgs
 
       . setStrongFlags strongFlags
@@ -201,6 +203,7 @@ planPackages verbosity comp platform mSandboxPkgInfo freezeFlags
     benchmarksEnabled = fromFlagOrDefault False $ freezeBenchmarks freezeFlags
 
     reorderGoals     = fromFlag (freezeReorderGoals     freezeFlags)
+    countConflicts   = fromFlag (freezeCountConflicts   freezeFlags)
     independentGoals = fromFlag (freezeIndependentGoals freezeFlags)
     shadowPkgs       = fromFlag (freezeShadowPkgs       freezeFlags)
     strongFlags      = fromFlag (freezeStrongFlags      freezeFlags)

cabal-install/Distribution/Client/Install.hs

@@ -379,6 +379,8 @@ planPackages comp platform mSandboxPkgInfo solver
 
       . setReorderGoals reorderGoals
 
+      . setCountConflicts countConflicts
+
       . setAvoidReinstalls avoidReinstalls
 
       . setShadowPkgs shadowPkgs
@@ -431,6 +433,7 @@ planPackages comp platform mSandboxPkgInfo solver
     reinstall        = fromFlag (installOverrideReinstall installFlags) ||
                        fromFlag (installReinstall         installFlags)
     reorderGoals     = fromFlag (installReorderGoals      installFlags)
+    countConflicts   = fromFlag (installCountConflicts    installFlags)
     independentGoals = fromFlag (installIndependentGoals  installFlags)
     avoidReinstalls  = fromFlag (installAvoidReinstalls   installFlags)
     shadowPkgs       = fromFlag (installShadowPkgs        installFlags)

cabal-install/Distribution/Client/ProjectConfig.hs

@@ -196,6 +196,7 @@ resolveSolverSettings ProjectConfig{
                                        n | n < 0     -> Nothing
                                          | otherwise -> Just n
     solverSettingReorderGoals      = fromFlag projectConfigReorderGoals
+    solverSettingCountConflicts    = fromFlag projectConfigCountConflicts
     solverSettingStrongFlags       = fromFlag projectConfigStrongFlags
   --solverSettingIndependentGoals  = fromFlag projectConfigIndependentGoals
   --solverSettingShadowPkgs        = fromFlag projectConfigShadowPkgs
@@ -211,6 +212,7 @@ resolveSolverSettings ProjectConfig{
        projectConfigAllowNewer        = Just AllowNewerNone,
        projectConfigMaxBackjumps      = Flag defaultMaxBackjumps,
        projectConfigReorderGoals      = Flag (ReorderGoals False),
+       projectConfigCountConflicts    = Flag (CountConflicts True),
        projectConfigStrongFlags       = Flag (StrongFlags False)
      --projectConfigIndependentGoals  = Flag False,
      --projectConfigShadowPkgs        = Flag False,

cabal-install/Distribution/Client/ProjectConfig/Legacy.hs

@@ -303,6 +303,7 @@ convertLegacyAllPackageFlags globalFlags configFlags
       installMaxBackjumps       = projectConfigMaxBackjumps,
     --installUpgradeDeps        = projectConfigUpgradeDeps,
       installReorderGoals       = projectConfigReorderGoals,
+      installCountConflicts     = projectConfigCountConflicts,
     --installIndependentGoals   = projectConfigIndependentGoals,
     --installShadowPkgs         = projectConfigShadowPkgs,
       installStrongFlags        = projectConfigStrongFlags
@@ -495,6 +496,7 @@ convertToLegacySharedConfig
       installMaxBackjumps      = projectConfigMaxBackjumps,
       installUpgradeDeps       = mempty, --projectConfigUpgradeDeps,
       installReorderGoals      = projectConfigReorderGoals,
+      installCountConflicts    = projectConfigCountConflicts,
       installIndependentGoals  = mempty, --projectConfigIndependentGoals,
       installShadowPkgs        = mempty, --projectConfigShadowPkgs,
       installStrongFlags       = projectConfigStrongFlags,
@@ -827,7 +829,7 @@ legacySharedConfigFieldDescrs =
       , "remote-build-reporting", "report-planning-failure"
       , "one-shot", "jobs", "keep-going", "offline"
         -- solver flags:
-      , "max-backjumps", "reorder-goals", "strong-flags"
+      , "max-backjumps", "reorder-goals", "count-conflicts", "strong-flags"
       ]
   . commandOptionsToFields
   ) (installOptions ParseArgs)

cabal-install/Distribution/Client/ProjectConfig/Types.hs

@@ -165,6 +165,7 @@ data ProjectConfigShared
        projectConfigAllowNewer        :: Maybe AllowNewer,
        projectConfigMaxBackjumps      :: Flag Int,
        projectConfigReorderGoals      :: Flag ReorderGoals,
+       projectConfigCountConflicts    :: Flag CountConflicts,
        projectConfigStrongFlags       :: Flag StrongFlags
 
        -- More things that only make sense for manual mode, not --local mode
@@ -319,6 +320,7 @@ data SolverSettings
        solverSettingAllowNewer        :: AllowNewer,
        solverSettingMaxBackjumps      :: Maybe Int,
        solverSettingReorderGoals      :: ReorderGoals,
+       solverSettingCountConflicts    :: CountConflicts,
        solverSettingStrongFlags       :: StrongFlags
        -- Things that only make sense for manual mode, not --local mode
        -- too much control!

cabal-install/Distribution/Client/ProjectPlanning.hs

@@ -865,6 +865,8 @@ planPackages comp platform solver SolverSettings{..}
 
       . setReorderGoals solverSettingReorderGoals
 
+      . setCountConflicts solverSettingCountConflicts
+
         --TODO: [required eventually] should only be configurable for custom installs
    -- . setAvoidReinstalls solverSettingAvoidReinstalls
 

cabal-install/Distribution/Client/Setup.hs

@@ -606,6 +606,7 @@ data FetchFlags = FetchFlags {
       fetchSolver           :: Flag PreSolver,
       fetchMaxBackjumps     :: Flag Int,
       fetchReorderGoals     :: Flag ReorderGoals,
+      fetchCountConflicts   :: Flag CountConflicts,
       fetchIndependentGoals :: Flag IndependentGoals,
       fetchShadowPkgs       :: Flag ShadowPkgs,
       fetchStrongFlags      :: Flag StrongFlags,
@@ -620,6 +621,7 @@ defaultFetchFlags = FetchFlags {
     fetchSolver           = Flag defaultSolver,
     fetchMaxBackjumps     = Flag defaultMaxBackjumps,
     fetchReorderGoals     = Flag (ReorderGoals False),
+    fetchCountConflicts   = Flag (CountConflicts True),
     fetchIndependentGoals = Flag (IndependentGoals False),
     fetchShadowPkgs       = Flag (ShadowPkgs False),
     fetchStrongFlags      = Flag (StrongFlags False),
@@ -666,6 +668,7 @@ fetchCommand = CommandUI {
        optionSolverFlags showOrParseArgs
                          fetchMaxBackjumps     (\v flags -> flags { fetchMaxBackjumps     = v })
                          fetchReorderGoals     (\v flags -> flags { fetchReorderGoals     = v })
+                         fetchCountConflicts   (\v flags -> flags { fetchCountConflicts   = v })
                          fetchIndependentGoals (\v flags -> flags { fetchIndependentGoals = v })
                          fetchShadowPkgs       (\v flags -> flags { fetchShadowPkgs       = v })
                          fetchStrongFlags      (\v flags -> flags { fetchStrongFlags      = v })
@@ -683,6 +686,7 @@ data FreezeFlags = FreezeFlags {
       freezeSolver           :: Flag PreSolver,
       freezeMaxBackjumps     :: Flag Int,
       freezeReorderGoals     :: Flag ReorderGoals,
+      freezeCountConflicts   :: Flag CountConflicts,
       freezeIndependentGoals :: Flag IndependentGoals,
       freezeShadowPkgs       :: Flag ShadowPkgs,
       freezeStrongFlags      :: Flag StrongFlags,
@@ -697,6 +701,7 @@ defaultFreezeFlags = FreezeFlags {
     freezeSolver           = Flag defaultSolver,
     freezeMaxBackjumps     = Flag defaultMaxBackjumps,
     freezeReorderGoals     = Flag (ReorderGoals False),
+    freezeCountConflicts   = Flag (CountConflicts True),
     freezeIndependentGoals = Flag (IndependentGoals False),
     freezeShadowPkgs       = Flag (ShadowPkgs False),
     freezeStrongFlags      = Flag (StrongFlags False),
@@ -742,6 +747,7 @@ freezeCommand = CommandUI {
        optionSolverFlags showOrParseArgs
                          freezeMaxBackjumps     (\v flags -> flags { freezeMaxBackjumps     = v })
                          freezeReorderGoals     (\v flags -> flags { freezeReorderGoals     = v })
+                         freezeCountConflicts   (\v flags -> flags { freezeCountConflicts   = v })
                          freezeIndependentGoals (\v flags -> flags { freezeIndependentGoals = v })
                          freezeShadowPkgs       (\v flags -> flags { freezeShadowPkgs       = v })
                          freezeStrongFlags      (\v flags -> flags { freezeStrongFlags      = v })
@@ -1144,6 +1150,7 @@ data InstallFlags = InstallFlags {
     installDryRun           :: Flag Bool,
     installMaxBackjumps     :: Flag Int,
     installReorderGoals     :: Flag ReorderGoals,
+    installCountConflicts   :: Flag CountConflicts,
     installIndependentGoals :: Flag IndependentGoals,
     installShadowPkgs       :: Flag ShadowPkgs,
     installStrongFlags      :: Flag StrongFlags,
@@ -1176,6 +1183,7 @@ defaultInstallFlags = InstallFlags {
     installDryRun          = Flag False,
     installMaxBackjumps    = Flag defaultMaxBackjumps,
     installReorderGoals    = Flag (ReorderGoals False),
+    installCountConflicts  = Flag (CountConflicts True),
     installIndependentGoals= Flag (IndependentGoals False),
     installShadowPkgs      = Flag (ShadowPkgs False),
     installStrongFlags     = Flag (StrongFlags False),
@@ -1321,6 +1329,7 @@ installOptions showOrParseArgs =
       optionSolverFlags showOrParseArgs
                         installMaxBackjumps     (\v flags -> flags { installMaxBackjumps     = v })
                         installReorderGoals     (\v flags -> flags { installReorderGoals     = v })
+                        installCountConflicts   (\v flags -> flags { installCountConflicts   = v })
                         installIndependentGoals (\v flags -> flags { installIndependentGoals = v })
                         installShadowPkgs       (\v flags -> flags { installShadowPkgs       = v })
                         installStrongFlags      (\v flags -> flags { installStrongFlags      = v }) ++
@@ -2085,11 +2094,12 @@ optionSolver get set =
 optionSolverFlags :: ShowOrParseArgs
                   -> (flags -> Flag Int   ) -> (Flag Int    -> flags -> flags)
                   -> (flags -> Flag ReorderGoals)     -> (Flag ReorderGoals     -> flags -> flags)
+                  -> (flags -> Flag CountConflicts)   -> (Flag CountConflicts   -> flags -> flags)
                   -> (flags -> Flag IndependentGoals) -> (Flag IndependentGoals -> flags -> flags)
                   -> (flags -> Flag ShadowPkgs)       -> (Flag ShadowPkgs       -> flags -> flags)
                   -> (flags -> Flag StrongFlags)      -> (Flag StrongFlags      -> flags -> flags)
                   -> [OptionField flags]
-optionSolverFlags showOrParseArgs getmbj setmbj getrg setrg _getig _setig getsip setsip getstrfl setstrfl =
+optionSolverFlags showOrParseArgs getmbj setmbj getrg setrg getcc setcc _getig _setig getsip setsip getstrfl setstrfl =
   [ option [] ["max-backjumps"]
       ("Maximum number of backjumps allowed while solving (default: " ++ show defaultMaxBackjumps ++ "). Use a negative number to enable unlimited backtracking. Use 0 to disable backtracking completely.")
       getmbj setmbj
@@ -2100,6 +2110,11 @@ optionSolverFlags showOrParseArgs getmbj setmbj getrg setrg _getig _setig getsip
       (fmap asBool . getrg)
       (setrg . fmap ReorderGoals)
       (yesNoOpt showOrParseArgs)
+  , option [] ["count-conflicts"]
+      "Try to speed up solving by preferring goals that are involved in a lot of conflicts (default)."
+      (fmap asBool . getcc)
+      (setcc . fmap CountConflicts)
+      (yesNoOpt showOrParseArgs)
   -- TODO: Disabled for now because it does not work as advertised (yet).
 {-
   , option [] ["independent-goals"]