Add stanza preferences to solver DSL.

cabal-install/tests/UnitTests/Distribution/Solver/Modular/DSL.hs

@@ -153,7 +153,9 @@ exFlag :: ExampleFlagName -> [ExampleDependency] -> [ExampleDependency]
        -> ExampleDependency
 exFlag n t e = ExFlag n (Buildable t) (Buildable e)
 
-data ExPreference = ExPref String ExampleVersionRange
+data ExPreference =
+    ExPkgPref ExamplePkgName ExampleVersionRange
+  | ExStanzaPref ExamplePkgName [OptionalStanza]
 
 data ExampleAvailable = ExAv {
     exAvName    :: ExamplePkgName
@@ -502,7 +504,9 @@ exResolve db exts langs pkgConfigDb targets solver mbj indepGoals reorder
                    $ setGoalOrder goalOrder
                    $ standardInstallPolicy instIdx avaiIdx targets'
     toLpc     pc = LabeledPackageConstraint pc ConstraintSourceUnknown
-    toPref (ExPref n v) = PackageVersionPreference (C.mkPackageName n) v
+
+    toPref (ExPkgPref n v)          = PackageVersionPreference (C.mkPackageName n) v
+    toPref (ExStanzaPref n stanzas) = PackageStanzasPreference (C.mkPackageName n) stanzas
 
     goalOrder :: Maybe (Variable P.QPN -> Variable P.QPN -> Ordering)
     goalOrder = (orderFromList . map toVariable) `fmap` vars

cabal-install/tests/UnitTests/Distribution/Solver/Modular/Solver.hs

@@ -111,16 +111,16 @@ tests = [
         ]
 
      , testGroup "Soft Constraints" [
-          runTest $ soft [ ExPref "A" $ mkvrThis 1]      $ mkTest db13 "selectPreferredVersionSimple" ["A"] (solverSuccess [("A", 1)])
-        , runTest $ soft [ ExPref "A" $ mkvrOrEarlier 2] $ mkTest db13 "selectPreferredVersionSimple2" ["A"] (solverSuccess [("A", 2)])
-        , runTest $ soft [ ExPref "A" $ mkvrOrEarlier 2
-                         , ExPref "A" $ mkvrOrEarlier 1] $ mkTest db13 "selectPreferredVersionMultiple" ["A"] (solverSuccess [("A", 1)])
-        , runTest $ soft [ ExPref "A" $ mkvrOrEarlier 1
-                         , ExPref "A" $ mkvrOrEarlier 2] $ mkTest db13 "selectPreferredVersionMultiple2" ["A"] (solverSuccess [("A", 1)])
-        , runTest $ soft [ ExPref "A" $ mkvrThis 1
-                         , ExPref "A" $ mkvrThis 2] $ mkTest db13 "selectPreferredVersionMultiple3" ["A"] (solverSuccess [("A", 2)])
-        , runTest $ soft [ ExPref "A" $ mkvrThis 1
-                         , ExPref "A" $ mkvrOrEarlier 2] $ mkTest db13 "selectPreferredVersionMultiple4" ["A"] (solverSuccess [("A", 1)])
+          runTest $ preferences [ ExPkgPref "A" $ mkvrThis 1]      $ mkTest db13 "selectPreferredVersionSimple" ["A"] (solverSuccess [("A", 1)])
+        , runTest $ preferences [ ExPkgPref "A" $ mkvrOrEarlier 2] $ mkTest db13 "selectPreferredVersionSimple2" ["A"] (solverSuccess [("A", 2)])
+        , runTest $ preferences [ ExPkgPref "A" $ mkvrOrEarlier 2
+                                , ExPkgPref "A" $ mkvrOrEarlier 1] $ mkTest db13 "selectPreferredVersionMultiple" ["A"] (solverSuccess [("A", 1)])
+        , runTest $ preferences [ ExPkgPref "A" $ mkvrOrEarlier 1
+                                , ExPkgPref "A" $ mkvrOrEarlier 2] $ mkTest db13 "selectPreferredVersionMultiple2" ["A"] (solverSuccess [("A", 1)])
+        , runTest $ preferences [ ExPkgPref "A" $ mkvrThis 1
+                                , ExPkgPref "A" $ mkvrThis 2] $ mkTest db13 "selectPreferredVersionMultiple3" ["A"] (solverSuccess [("A", 2)])
+        , runTest $ preferences [ ExPkgPref "A" $ mkvrThis 1
+                                , ExPkgPref "A" $ mkvrOrEarlier 2] $ mkTest db13 "selectPreferredVersionMultiple4" ["A"] (solverSuccess [("A", 1)])
         ]
      , testGroup "Buildable Field" [
           testBuildable "avoid building component with unknown dependency" (ExAny "unknown")
@@ -179,7 +179,6 @@ tests = [
         ]
     ]
   where
-    soft prefs test = test { testSoftConstraints = prefs }
     mkvrThis        = V.thisVersion . makeV
     mkvrOrEarlier   = V.orEarlierVersion . makeV
     makeV v         = V.mkVersion [v,0,0]
@@ -192,6 +191,9 @@ indep test = test { testIndepGoals = IndependentGoals True }
 goalOrder :: [ExampleVar] -> SolverTest -> SolverTest
 goalOrder order test = test { testGoalOrder = Just order }
 
+preferences :: [ExPreference] -> SolverTest -> SolverTest
+preferences prefs test = test { testSoftConstraints = prefs }
+
 data GoalOrder = FixedGoalOrder | DefaultGoalOrder
 
 {-------------------------------------------------------------------------------