Solver feature: soft prefs for enabling testsuites/benchmarks

cabal-install/Distribution/Client/Dependency.hs

@@ -70,7 +70,8 @@ import qualified Distribution.Client.InstallPlan as InstallPlan
 import Distribution.Client.InstallPlan (InstallPlan)
 import Distribution.Client.Types
          ( SourcePackageDb(SourcePackageDb), SourcePackage(..)
-         , ConfiguredPackage(..), ConfiguredId(..), enableStanzas )
+         , ConfiguredPackage(..), ConfiguredId(..)
+         , OptionalStanza(..), enableStanzas )
 import Distribution.Client.Dependency.Types
          ( PreSolver(..), Solver(..), DependencyResolver, ResolverPackage(..)
          , PackageConstraint(..), showPackageConstraint
@@ -116,7 +117,7 @@ import Distribution.Verbosity
          ( Verbosity )
 
 import Data.List
-         ( foldl', sort, sortBy, nubBy, maximumBy, intercalate )
+         ( foldl', sort, sortBy, nubBy, maximumBy, intercalate, nub )
 import Data.Function (on)
 import Data.Maybe (fromMaybe)
 import qualified Data.Map as Map
@@ -178,6 +179,11 @@ data PackagePreference =
      -- | If we prefer versions of packages that are already installed.
    | PackageInstalledPreference PackageName InstalledPreference
 
+     -- | If we would prefer to enable these optional stanzas
+     -- (i.e. test suites and/or benchmarks)
+   | PackageStanzasPreference   PackageName [OptionalStanza]
+
+
 -- | Provide a textual representation of a package preference
 -- for debugging purposes.
 --
@@ -186,6 +192,8 @@ showPackagePreference (PackageVersionPreference   pn vr) =
   display pn ++ " " ++ display (simplifyVersionRange vr)
 showPackagePreference (PackageInstalledPreference pn ip) =
   display pn ++ " " ++ show ip
+showPackagePreference (PackageStanzasPreference pn st) =
+  display pn ++ " " ++ show st
 
 basicDepResolverParams :: InstalledPackageIndex
                        -> PackageIndex.PackageIndex SourcePackage
@@ -586,7 +594,9 @@ interpretPackagesPreference :: Set PackageName
                             -> [PackagePreference]
                             -> (PackageName -> PackagePreferences)
 interpretPackagesPreference selected defaultPref prefs =
-  \pkgname -> PackagePreferences (versionPref pkgname) (installPref pkgname)
+  \pkgname -> PackagePreferences (versionPref pkgname)
+                                 (installPref pkgname)
+                                 (stanzasPref pkgname)
   where
     versionPref pkgname =
       fromMaybe [anyVersion] (Map.lookup pkgname versionPrefs)
@@ -608,6 +618,13 @@ interpretPackagesPreference selected defaultPref prefs =
         if pkgname `Set.member` selected then PreferLatest
                                          else PreferInstalled
 
+    stanzasPref pkgname =
+      fromMaybe [] (Map.lookup pkgname stanzasPrefs)
+    stanzasPrefs = Map.fromListWith (\a b -> nub (a ++ b))
+      [ (pkgname, pref)
+      | PackageStanzasPreference pkgname pref <- prefs ]
+
+
 -- ------------------------------------------------------------
 -- * Checking the result of the solver
 -- ------------------------------------------------------------
@@ -806,7 +823,7 @@ resolveWithoutDependencies (DepResolverParams targets constraints
                                                          pkgDependency
 
         -- Preferences
-        PackagePreferences preferredVersions preferInstalled
+        PackagePreferences preferredVersions preferInstalled _
           = packagePreferences pkgname
 
         bestByPrefs   = comparing $ \pkg ->

cabal-install/Distribution/Client/Dependency/Modular/Builder.hs

@@ -142,6 +142,11 @@ build = ana go
         reorder False = reverse
         trivial = L.null t && L.null f
 
+    -- For a stanza, we also create only two subtrees. The order is initially
+    -- False, True. This can be changed later by constraints (force enabling
+    -- the stanza by replacing the False branch with failure) or preferences
+    -- (try enabling the stanza if possible by moving the True branch first).
+
     go bs@(BS { next = OneGoal (OpenGoal (Stanza qsn@(SN (PI qpn _) _) t) gr) }) =
       SChoiceF qsn gr trivial (P.fromList
         [(False,                                                                  bs  { next = Goals }),

cabal-install/Distribution/Client/Dependency/Modular/ConfiguredConversion.hs

@@ -20,17 +20,20 @@ import Distribution.Client.ComponentDeps (ComponentDeps)
 -- | Converts from the solver specific result @CP QPN@ into
 -- a 'ResolverPackage', which can then be converted into
 -- the install plan.
-convCP :: SI.InstalledPackageIndex -> CI.PackageIndex SourcePackage ->
+convCP :: SI.InstalledPackageIndex ->
+          CI.PackageIndex SourcePackage ->
           CP QPN -> ResolverPackage
 convCP iidx sidx (CP qpi fa es ds) =
   case convPI qpi of
     Left  pi -> PreExisting
                   (fromJust $ SI.lookupUnitId iidx pi)
     Right pi -> Configured $ ConfiguredPackage
-                  (fromJust $ CI.lookupPackageId sidx pi)
+                  srcpkg
                   fa
                   es
                   ds'
+      where
+        Just srcpkg = CI.lookupPackageId sidx pi
   where
     ds' :: ComponentDeps [ConfiguredId]
     ds' = fmap (map convConfId) ds

cabal-install/Distribution/Client/Dependency/Modular/Preference.hs

@@ -79,12 +79,13 @@ preferredVersionsOrdering vrs v1 v2 = compare (check v1) (check v2)
                Prelude.map (flip checkVR v) $ vrs
 
 -- | Traversal that tries to establish package preferences (not constraints).
--- Works by reordering choice nodes.
+-- Works by reordering choice nodes. Also applies stanza preferences.
 preferPackagePreferences :: (PN -> PackagePreferences) -> Tree a -> Tree a
-preferPackagePreferences pcs = packageOrderFor (const True) preference
+preferPackagePreferences pcs = preferPackageStanzaPreferences pcs
+                             . packageOrderFor (const True) preference
   where
     preference pn i1@(I v1 _) i2@(I v2 _) =
-      let PackagePreferences vrs ipref = pcs pn
+      let PackagePreferences vrs ipref _ = pcs pn
       in  preferredVersionsOrdering vrs v1 v2 `mappend` -- combines lexically
           locationsOrdering ipref i1 i2
 
@@ -107,6 +108,20 @@ preferInstalledOrdering _              _              = EQ
 preferLatestOrdering :: I -> I -> Ordering
 preferLatestOrdering (I v1 _) (I v2 _) = compare v1 v2
 
+-- | Traversal that tries to establish package stanza enable\/disable
+-- preferences. Works by reordering the branches of stanza choices.
+preferPackageStanzaPreferences :: (PN -> PackagePreferences) -> Tree a -> Tree a
+preferPackageStanzaPreferences pcs = trav go
+  where
+    go (SChoiceF qsn@(SN (PI (Q pp pn) _) s) gr _tr ts) | primaryPP pp =
+        let PackagePreferences _ _ spref = pcs pn
+            enableStanzaPref = s `elem` spref
+                  -- move True case first to try enabling the stanza
+            ts' | enableStanzaPref = P.sortByKeys (flip compare) ts
+                | otherwise        = ts
+         in SChoiceF qsn gr True ts'   -- True: now weak choice
+    go x = x
+
 -- | Helper function that tries to enforce a single package constraint on a
 -- given instance for a P-node. Translates the constraint into a
 -- tree-transformer that either leaves the subtree untouched, or replaces it

cabal-install/Distribution/Client/Dependency/TopDown.hs

@@ -130,7 +130,7 @@ explore pref (ChoiceNode _ choices)  =
         isPreferred p = length . filter (packageVersion p `withinRange`) $
                         preferredVersions
 
-        (PackagePreferences preferredVersions packageInstalledPreference)
+        (PackagePreferences preferredVersions packageInstalledPreference _)
           = pref pkgname
 
     logInfo node = Select selected discarded
@@ -674,7 +674,7 @@ finaliseSelectedPackages pref selected constraints =
           | bounded   = boundedRank -- this is a dummy constant
           | otherwise = length . filter (packageVersion p `withinRange`) $
                         preferredVersions
-          where (PackagePreferences preferredVersions _) = pref (packageName p)
+          where (PackagePreferences preferredVersions _ _) = pref (packageName p)
         boundedRank = 0 -- any value will do
 
         boundedAbove :: VersionRange -> Bool

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

@@ -176,7 +176,9 @@ showPackageConstraint (PackageConstraintStanzas pn ss) =
 -- It is not specified if preferences on some packages are more important than
 -- others.
 --
-data PackagePreferences = PackagePreferences [VersionRange] InstalledPreference
+data PackagePreferences = PackagePreferences [VersionRange]
+                                             InstalledPreference
+                                             [OptionalStanza]
 
 -- | Whether we prefer an installed version of a package or simply the latest
 -- version.