Merge pull request #5680 from grayjay/find-minimal-conflict-set

Solver: Improve error message by finding a minimal conflict set (issue #5647).
haskell · Dec 5, 2018 · 009fb61 · 009fb61
2 parents c25a223 + 76adde4
commit 009fb61
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Showing 22 changed files with 436 additions and 108 deletions.
diff --git a/Cabal/doc/nix-local-build.rst b/Cabal/doc/nix-local-build.rst
@@ -2073,6 +2073,21 @@ Most users generally won't need these.
     The command line variant of this field is
     ``--(no-)count-conflicts``.
 
+.. cfg-field:: minimize-conflict-set: boolean
+               --minimize-conflict-set
+               --no-minimize-conflict-set
+    :synopsis: Try to improve the solver error message when there is no
+	       solution.
+
+    :default: False
+
+    When there is no solution, try to improve the solver error message
+    by finding a minimal conflict set. This option may increase run
+    time significantly, so it is off by default.
+
+    The command line variant of this field is
+    ``--(no-)minimize-conflict-set``.
+
 .. cfg-field:: strong-flags: boolean
                --strong-flags
                --no-strong-flags

diff --git a/cabal-install/Distribution/Client/Config.hs b/cabal-install/Distribution/Client/Config.hs
@@ -254,6 +254,7 @@ instance Semigroup SavedConfig where
         installMaxBackjumps          = combine installMaxBackjumps,
         installReorderGoals          = combine installReorderGoals,
         installCountConflicts        = combine installCountConflicts,
+        installMinimizeConflictSet   = combine installMinimizeConflictSet,
         installIndependentGoals      = combine installIndependentGoals,
         installShadowPkgs            = combine installShadowPkgs,
         installStrongFlags           = combine installStrongFlags,

diff --git a/cabal-install/Distribution/Client/Dependency.hs b/cabal-install/Distribution/Client/Dependency.hs
@@ -47,6 +47,7 @@ module Distribution.Client.Dependency (
     setPreferenceDefault,
     setReorderGoals,
     setCountConflicts,
+    setMinimizeConflictSet,
     setIndependentGoals,
     setAvoidReinstalls,
     setShadowPkgs,
@@ -158,6 +159,7 @@ data DepResolverParams = DepResolverParams {
        depResolverSourcePkgIndex    :: PackageIndex.PackageIndex UnresolvedSourcePackage,
        depResolverReorderGoals      :: ReorderGoals,
        depResolverCountConflicts    :: CountConflicts,
+       depResolverMinimizeConflictSet :: MinimizeConflictSet,
        depResolverIndependentGoals  :: IndependentGoals,
        depResolverAvoidReinstalls   :: AvoidReinstalls,
        depResolverShadowPkgs        :: ShadowPkgs,
@@ -195,6 +197,7 @@ showDepResolverParams p =
   ++ "\nstrategy: "          ++ show (depResolverPreferenceDefault        p)
   ++ "\nreorder goals: "     ++ show (asBool (depResolverReorderGoals     p))
   ++ "\ncount conflicts: "   ++ show (asBool (depResolverCountConflicts   p))
+  ++ "\nminimize conflict set: " ++ show (asBool (depResolverMinimizeConflictSet p))
   ++ "\nindependent goals: " ++ show (asBool (depResolverIndependentGoals p))
   ++ "\navoid reinstalls: "  ++ show (asBool (depResolverAvoidReinstalls  p))
   ++ "\nshadow packages: "   ++ show (asBool (depResolverShadowPkgs       p))
@@ -251,6 +254,7 @@ basicDepResolverParams installedPkgIndex sourcePkgIndex =
        depResolverSourcePkgIndex    = sourcePkgIndex,
        depResolverReorderGoals      = ReorderGoals False,
        depResolverCountConflicts    = CountConflicts True,
+       depResolverMinimizeConflictSet = MinimizeConflictSet False,
        depResolverIndependentGoals  = IndependentGoals False,
        depResolverAvoidReinstalls   = AvoidReinstalls False,
        depResolverShadowPkgs        = ShadowPkgs False,
@@ -306,6 +310,12 @@ setCountConflicts count params =
       depResolverCountConflicts = count
     }
 
+setMinimizeConflictSet :: MinimizeConflictSet -> DepResolverParams -> DepResolverParams
+setMinimizeConflictSet minimize params =
+    params {
+      depResolverMinimizeConflictSet = minimize
+    }
+
 setIndependentGoals :: IndependentGoals -> DepResolverParams -> DepResolverParams
 setIndependentGoals indep params =
     params {
@@ -745,8 +755,7 @@ resolveDependencies platform comp pkgConfigDB solver params =
 
     Step (showDepResolverParams finalparams)
   $ fmap (validateSolverResult platform comp indGoals)
-  $ runSolver solver (SolverConfig reordGoals cntConflicts
-                      indGoals noReinstalls
+  $ runSolver solver (SolverConfig reordGoals cntConflicts minimize indGoals noReinstalls
                       shadowing strFlags allowBootLibs onlyConstrained_ maxBkjumps enableBj
                       solveExes order verbosity (PruneAfterFirstSuccess False))
                      platform comp installedPkgIndex sourcePkgIndex
@@ -760,6 +769,7 @@ resolveDependencies platform comp pkgConfigDB solver params =
       sourcePkgIndex
       reordGoals
       cntConflicts
+      minimize
       indGoals
       noReinstalls
       shadowing
@@ -1005,9 +1015,10 @@ resolveWithoutDependencies :: DepResolverParams
                            -> Either [ResolveNoDepsError] [UnresolvedSourcePackage]
 resolveWithoutDependencies (DepResolverParams targets constraints
                               prefs defpref installedPkgIndex sourcePkgIndex
-                              _reorderGoals _countConflicts _indGoals _avoidReinstalls
-                              _shadowing _strFlags _maxBjumps _enableBj
-                              _solveExes _allowBootLibInstalls _onlyConstrained _order _verbosity) =
+                              _reorderGoals _countConflicts _minimizeConflictSet
+                              _indGoals _avoidReinstalls _shadowing _strFlags
+                              _maxBjumps _enableBj _solveExes
+                              _allowBootLibInstalls _onlyConstrained _order _verbosity) =
     collectEithers $ map selectPackage (Set.toList targets)
   where
     selectPackage :: PackageName -> Either ResolveNoDepsError UnresolvedSourcePackage

diff --git a/cabal-install/Distribution/Client/Fetch.hs b/cabal-install/Distribution/Client/Fetch.hs
@@ -162,6 +162,8 @@ planPackages verbosity comp platform fetchFlags
 
       . setCountConflicts countConflicts
 
+      . setMinimizeConflictSet minimizeConflictSet
+
       . setShadowPkgs shadowPkgs
 
       . setStrongFlags strongFlags
@@ -197,6 +199,7 @@ planPackages verbosity comp platform fetchFlags
 
     reorderGoals     = fromFlag (fetchReorderGoals     fetchFlags)
     countConflicts   = fromFlag (fetchCountConflicts   fetchFlags)
+    minimizeConflictSet = fromFlag (fetchMinimizeConflictSet fetchFlags)
     independentGoals = fromFlag (fetchIndependentGoals fetchFlags)
     shadowPkgs       = fromFlag (fetchShadowPkgs       fetchFlags)
     strongFlags      = fromFlag (fetchStrongFlags      fetchFlags)

diff --git a/cabal-install/Distribution/Client/Freeze.hs b/cabal-install/Distribution/Client/Freeze.hs
@@ -175,6 +175,8 @@ planPackages verbosity comp platform mSandboxPkgInfo freezeFlags
 
       . setCountConflicts countConflicts
 
+      . setMinimizeConflictSet minimizeConflictSet
+
       . setShadowPkgs shadowPkgs
 
       . setStrongFlags strongFlags
@@ -205,6 +207,7 @@ planPackages verbosity comp platform mSandboxPkgInfo freezeFlags
 
     reorderGoals     = fromFlag (freezeReorderGoals     freezeFlags)
     countConflicts   = fromFlag (freezeCountConflicts   freezeFlags)
+    minimizeConflictSet = fromFlag (freezeMinimizeConflictSet freezeFlags)
     independentGoals = fromFlag (freezeIndependentGoals freezeFlags)
     shadowPkgs       = fromFlag (freezeShadowPkgs       freezeFlags)
     strongFlags      = fromFlag (freezeStrongFlags      freezeFlags)

diff --git a/cabal-install/Distribution/Client/Install.hs b/cabal-install/Distribution/Client/Install.hs
@@ -389,6 +389,8 @@ planPackages verbosity comp platform mSandboxPkgInfo solver
 
       . setCountConflicts countConflicts
 
+      . setMinimizeConflictSet minimizeConflictSet
+
       . setAvoidReinstalls avoidReinstalls
 
       . setShadowPkgs shadowPkgs
@@ -455,6 +457,7 @@ planPackages verbosity comp platform mSandboxPkgInfo solver
                        fromFlag (installReinstall         installFlags)
     reorderGoals     = fromFlag (installReorderGoals      installFlags)
     countConflicts   = fromFlag (installCountConflicts    installFlags)
+    minimizeConflictSet = fromFlag (installMinimizeConflictSet installFlags)
     independentGoals = fromFlag (installIndependentGoals  installFlags)
     avoidReinstalls  = fromFlag (installAvoidReinstalls   installFlags)
     shadowPkgs       = fromFlag (installShadowPkgs        installFlags)

diff --git a/cabal-install/Distribution/Client/ProjectConfig.hs b/cabal-install/Distribution/Client/ProjectConfig.hs
@@ -238,6 +238,7 @@ resolveSolverSettings ProjectConfig{
                                          | otherwise -> Just n
     solverSettingReorderGoals      = fromFlag projectConfigReorderGoals
     solverSettingCountConflicts    = fromFlag projectConfigCountConflicts
+    solverSettingMinimizeConflictSet = fromFlag projectConfigMinimizeConflictSet
     solverSettingStrongFlags       = fromFlag projectConfigStrongFlags
     solverSettingAllowBootLibInstalls = fromFlag projectConfigAllowBootLibInstalls
     solverSettingOnlyConstrained   = fromFlag projectConfigOnlyConstrained
@@ -258,6 +259,7 @@ resolveSolverSettings ProjectConfig{
        projectConfigMaxBackjumps      = Flag defaultMaxBackjumps,
        projectConfigReorderGoals      = Flag (ReorderGoals False),
        projectConfigCountConflicts    = Flag (CountConflicts True),
+       projectConfigMinimizeConflictSet = Flag (MinimizeConflictSet False),
        projectConfigStrongFlags       = Flag (StrongFlags False),
        projectConfigAllowBootLibInstalls = Flag (AllowBootLibInstalls False),
        projectConfigOnlyConstrained   = Flag OnlyConstrainedNone,

diff --git a/cabal-install/Distribution/Client/ProjectConfig/Legacy.hs b/cabal-install/Distribution/Client/ProjectConfig/Legacy.hs
@@ -352,6 +352,7 @@ convertLegacyAllPackageFlags globalFlags configFlags
     --installUpgradeDeps        = projectConfigUpgradeDeps,
       installReorderGoals       = projectConfigReorderGoals,
       installCountConflicts     = projectConfigCountConflicts,
+      installMinimizeConflictSet = projectConfigMinimizeConflictSet,
       installPerComponent       = projectConfigPerComponent,
       installIndependentGoals   = projectConfigIndependentGoals,
     --installShadowPkgs         = projectConfigShadowPkgs,
@@ -577,6 +578,7 @@ convertToLegacySharedConfig
       installUpgradeDeps       = mempty, --projectConfigUpgradeDeps,
       installReorderGoals      = projectConfigReorderGoals,
       installCountConflicts    = projectConfigCountConflicts,
+      installMinimizeConflictSet = projectConfigMinimizeConflictSet,
       installIndependentGoals  = projectConfigIndependentGoals,
       installShadowPkgs        = mempty, --projectConfigShadowPkgs,
       installStrongFlags       = projectConfigStrongFlags,
@@ -954,7 +956,8 @@ legacySharedConfigFieldDescrs =
       , "remote-build-reporting", "report-planning-failure"
       , "one-shot", "jobs", "keep-going", "offline", "per-component"
         -- solver flags:
-      , "max-backjumps", "reorder-goals", "count-conflicts", "independent-goals"
+      , "max-backjumps", "reorder-goals", "count-conflicts"
+      , "minimize-conflict-set", "independent-goals"
       , "strong-flags" , "allow-boot-library-installs", "reject-unconstrained-dependencies", "index-state"
       ]
   . commandOptionsToFields

diff --git a/cabal-install/Distribution/Client/ProjectConfig/Types.hs b/cabal-install/Distribution/Client/ProjectConfig/Types.hs
@@ -193,6 +193,7 @@ data ProjectConfigShared
        projectConfigMaxBackjumps      :: Flag Int,
        projectConfigReorderGoals      :: Flag ReorderGoals,
        projectConfigCountConflicts    :: Flag CountConflicts,
+       projectConfigMinimizeConflictSet :: Flag MinimizeConflictSet,
        projectConfigStrongFlags       :: Flag StrongFlags,
        projectConfigAllowBootLibInstalls :: Flag AllowBootLibInstalls,
        projectConfigOnlyConstrained   :: Flag OnlyConstrained,
@@ -383,6 +384,7 @@ data SolverSettings
        solverSettingMaxBackjumps      :: Maybe Int,
        solverSettingReorderGoals      :: ReorderGoals,
        solverSettingCountConflicts    :: CountConflicts,
+       solverSettingMinimizeConflictSet :: MinimizeConflictSet,
        solverSettingStrongFlags       :: StrongFlags,
        solverSettingAllowBootLibInstalls :: AllowBootLibInstalls,
        solverSettingOnlyConstrained   :: OnlyConstrained,

diff --git a/cabal-install/Distribution/Client/ProjectPlanning.hs b/cabal-install/Distribution/Client/ProjectPlanning.hs
@@ -951,6 +951,8 @@ planPackages verbosity comp platform solver SolverSettings{..}
 
       . setCountConflicts solverSettingCountConflicts
 
+      . setMinimizeConflictSet solverSettingMinimizeConflictSet
+
         --TODO: [required eventually] should only be configurable for
         --custom installs
    -- . setAvoidReinstalls solverSettingAvoidReinstalls

diff --git a/cabal-install/Distribution/Client/Setup.hs b/cabal-install/Distribution/Client/Setup.hs
@@ -973,6 +973,7 @@ data FetchFlags = FetchFlags {
       fetchMaxBackjumps     :: Flag Int,
       fetchReorderGoals     :: Flag ReorderGoals,
       fetchCountConflicts   :: Flag CountConflicts,
+      fetchMinimizeConflictSet :: Flag MinimizeConflictSet,
       fetchIndependentGoals :: Flag IndependentGoals,
       fetchShadowPkgs       :: Flag ShadowPkgs,
       fetchStrongFlags      :: Flag StrongFlags,
@@ -992,6 +993,7 @@ defaultFetchFlags = FetchFlags {
     fetchMaxBackjumps     = Flag defaultMaxBackjumps,
     fetchReorderGoals     = Flag (ReorderGoals False),
     fetchCountConflicts   = Flag (CountConflicts True),
+    fetchMinimizeConflictSet = Flag (MinimizeConflictSet False),
     fetchIndependentGoals = Flag (IndependentGoals False),
     fetchShadowPkgs       = Flag (ShadowPkgs False),
     fetchStrongFlags      = Flag (StrongFlags False),
@@ -1053,6 +1055,7 @@ fetchCommand = CommandUI {
                          fetchMaxBackjumps     (\v flags -> flags { fetchMaxBackjumps     = v })
                          fetchReorderGoals     (\v flags -> flags { fetchReorderGoals     = v })
                          fetchCountConflicts   (\v flags -> flags { fetchCountConflicts   = v })
+                         fetchMinimizeConflictSet (\v flags -> flags { fetchMinimizeConflictSet = v })
                          fetchIndependentGoals (\v flags -> flags { fetchIndependentGoals = v })
                          fetchShadowPkgs       (\v flags -> flags { fetchShadowPkgs       = v })
                          fetchStrongFlags      (\v flags -> flags { fetchStrongFlags      = v })
@@ -1073,6 +1076,7 @@ data FreezeFlags = FreezeFlags {
       freezeMaxBackjumps     :: Flag Int,
       freezeReorderGoals     :: Flag ReorderGoals,
       freezeCountConflicts   :: Flag CountConflicts,
+      freezeMinimizeConflictSet :: Flag MinimizeConflictSet,
       freezeIndependentGoals :: Flag IndependentGoals,
       freezeShadowPkgs       :: Flag ShadowPkgs,
       freezeStrongFlags      :: Flag StrongFlags,
@@ -1090,6 +1094,7 @@ defaultFreezeFlags = FreezeFlags {
     freezeMaxBackjumps     = Flag defaultMaxBackjumps,
     freezeReorderGoals     = Flag (ReorderGoals False),
     freezeCountConflicts   = Flag (CountConflicts True),
+    freezeMinimizeConflictSet = Flag (MinimizeConflictSet False),
     freezeIndependentGoals = Flag (IndependentGoals False),
     freezeShadowPkgs       = Flag (ShadowPkgs False),
     freezeStrongFlags      = Flag (StrongFlags False),
@@ -1142,6 +1147,7 @@ freezeCommand = CommandUI {
                          freezeMaxBackjumps     (\v flags -> flags { freezeMaxBackjumps     = v })
                          freezeReorderGoals     (\v flags -> flags { freezeReorderGoals     = v })
                          freezeCountConflicts   (\v flags -> flags { freezeCountConflicts   = v })
+                         freezeMinimizeConflictSet (\v flags -> flags { freezeMinimizeConflictSet = v })
                          freezeIndependentGoals (\v flags -> flags { freezeIndependentGoals = v })
                          freezeShadowPkgs       (\v flags -> flags { freezeShadowPkgs       = v })
                          freezeStrongFlags      (\v flags -> flags { freezeStrongFlags      = v })
@@ -1711,6 +1717,7 @@ data InstallFlags = InstallFlags {
     installMaxBackjumps     :: Flag Int,
     installReorderGoals     :: Flag ReorderGoals,
     installCountConflicts   :: Flag CountConflicts,
+    installMinimizeConflictSet :: Flag MinimizeConflictSet,
     installIndependentGoals :: Flag IndependentGoals,
     installShadowPkgs       :: Flag ShadowPkgs,
     installStrongFlags      :: Flag StrongFlags,
@@ -1757,6 +1764,7 @@ defaultInstallFlags = InstallFlags {
     installMaxBackjumps    = Flag defaultMaxBackjumps,
     installReorderGoals    = Flag (ReorderGoals False),
     installCountConflicts  = Flag (CountConflicts True),
+    installMinimizeConflictSet = Flag (MinimizeConflictSet False),
     installIndependentGoals= Flag (IndependentGoals False),
     installShadowPkgs      = Flag (ShadowPkgs False),
     installStrongFlags     = Flag (StrongFlags False),
@@ -1968,6 +1976,7 @@ installOptions showOrParseArgs =
                         installMaxBackjumps     (\v flags -> flags { installMaxBackjumps     = v })
                         installReorderGoals     (\v flags -> flags { installReorderGoals     = v })
                         installCountConflicts   (\v flags -> flags { installCountConflicts   = v })
+                        installMinimizeConflictSet (\v flags -> flags { installMinimizeConflictSet = v })
                         installIndependentGoals (\v flags -> flags { installIndependentGoals = v })
                         installShadowPkgs       (\v flags -> flags { installShadowPkgs       = v })
                         installStrongFlags      (\v flags -> flags { installStrongFlags      = v })
@@ -2778,14 +2787,16 @@ 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 MinimizeConflictSet) -> (Flag MinimizeConflictSet -> flags -> flags)
                   -> (flags -> Flag IndependentGoals) -> (Flag IndependentGoals -> flags -> flags)
                   -> (flags -> Flag ShadowPkgs)       -> (Flag ShadowPkgs       -> flags -> flags)
                   -> (flags -> Flag StrongFlags)      -> (Flag StrongFlags      -> flags -> flags)
                   -> (flags -> Flag AllowBootLibInstalls) -> (Flag AllowBootLibInstalls -> flags -> flags)
                   -> (flags -> Flag OnlyConstrained)  -> (Flag OnlyConstrained  -> flags -> flags)
                   -> [OptionField flags]
-optionSolverFlags showOrParseArgs getmbj setmbj getrg setrg getcc setcc getig setig
-                  getsip setsip getstrfl setstrfl getib setib getoc setoc =
+optionSolverFlags showOrParseArgs getmbj setmbj getrg setrg getcc setcc
+                  getmc setmc getig setig getsip setsip getstrfl setstrfl
+                  getib setib getoc setoc =
   [ 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
@@ -2801,6 +2812,13 @@ optionSolverFlags showOrParseArgs getmbj setmbj getrg setrg getcc setcc getig se
       (fmap asBool . getcc)
       (setcc . fmap CountConflicts)
       (yesNoOpt showOrParseArgs)
+  , option [] ["minimize-conflict-set"]
+      ("When there is no solution, try to improve the error message by finding "
+        ++ "a minimal conflict set (default: false). May increase run time "
+        ++ "significantly.")
+      (fmap asBool . getmc)
+      (setmc . fmap MinimizeConflictSet)
+      (yesNoOpt showOrParseArgs)
   , option [] ["independent-goals"]
       "Treat several goals on the command line as independent. If several goals depend on the same package, different versions can be chosen."
       (fmap asBool . getig)