Server: Use a bespoke type for nullability instead of Bool

GitOrigin-RevId: a793c7a921174611d44b7e7cdc1dc43b132376fe

server/src-lib/Hasura/GraphQL/Schema/Select.hs

@@ -1020,7 +1020,7 @@ relationshipField sourceName relationshipInfo = runMaybeT do
     ObjRel -> do
       let desc = Just $ G.Description "An object relationship"
       selectionSetParser <- lift $ tableSelectionSet sourceName otherTableInfo remotePerms
-      pure $ pure $ (if nullable then id else P.nonNullableField) $
+      pure $ pure $ case nullable of { Nullable -> id; NotNullable -> P.nonNullableField} $
         P.subselection_ relFieldName desc selectionSetParser
              <&> \fields -> IR.AFObjectRelation $ IR.AnnRelationSelectG relName colMapping $
                     IR.AnnObjectSelectG fields otherTableName $

server/src-lib/Hasura/RQL/DDL/Relationship.hs

@@ -130,7 +130,7 @@ objRelP2Setup source qt foreignKeys (RelDef rn ru _) fieldInfoMap = case ru of
                                               reason
         dependencies = map (mkDependency qt DRLeftColumn) lCols
                     <> map (mkDependency refqt DRRightColumn) rCols
-    pure (RelInfo rn ObjRel (rmColumns rm) refqt True True io, dependencies)
+    pure (RelInfo rn ObjRel (rmColumns rm) refqt True Nullable io, dependencies)
   RUFKeyOn (SameTable columns) -> do
     foreignTableForeignKeys <- findTable @b qt foreignKeys
     ForeignKey constraint foreignTable colMap <- getRequiredFkey columns (HS.toList foreignTableForeignKeys)
@@ -151,7 +151,7 @@ objRelP2Setup source qt foreignKeys (RelDef rn ru _) fieldInfoMap = case ru of
           ] <> fmap (drUsingColumnDep @b source qt) (toList columns)
     colInfo <- traverse ((`HM.lookup` fieldInfoMap) . fromCol @b) columns
                  `onNothing` throw500 "could not find column info in schema cache"
-    let nullable = all pgiIsNullable colInfo
+    let nullable = boolToNullable $ all pgiIsNullable colInfo
     pure (RelInfo rn ObjRel colMap foreignTable False nullable BeforeParent, dependencies)
   RUFKeyOn (RemoteTable remoteTable remoteCols) ->
     mkFkeyRel ObjRel AfterParent source rn qt remoteTable remoteCols foreignKeys
@@ -181,7 +181,7 @@ arrRelP2Setup foreignKeys source qt (RelDef rn ru _) = case ru of
                                     $ TOCol @b c)
                                   DRRightColumn)
                   rCols
-    pure (RelInfo rn ArrRel (rmColumns rm) refqt True True AfterParent, deps)
+    pure (RelInfo rn ArrRel (rmColumns rm) refqt True Nullable AfterParent, deps)
   RUFKeyOn (ArrRelUsingFKeyOn refqt refCols) ->
     mkFkeyRel ArrRel AfterParent source rn qt refqt refCols foreignKeys
 
@@ -215,7 +215,7 @@ mkFkeyRel relType io source rn sourceTable remoteTable remoteColumns foreignKeys
                 $ SOITable @b remoteTable)
               DRRemoteTable
           ] <> fmap (drUsingColumnDep @b source remoteTable) (toList remoteColumns)
-    pure (RelInfo rn relType (reverseHM colMap) remoteTable False False io, dependencies)
+    pure (RelInfo rn relType (reverseHM colMap) remoteTable False NotNullable io, dependencies)
   where
     reverseHM :: Eq y => Hashable y => HashMap x y -> HashMap y x
     reverseHM = HM.fromList . fmap swap . HM.toList

server/src-lib/Hasura/RQL/Types/Common.hs

@@ -79,8 +79,6 @@ import           Hasura.Base.Error
 import           Hasura.EncJSON
 import           Hasura.Incremental                 (Cacheable)
 import           Hasura.RQL.DDL.Headers             ()
-import           Hasura.RQL.Types.Backend
-import           Hasura.SQL.Backend                 (BackendType)
 import           Hasura.SQL.Types
 
 newtype RelName
@@ -153,26 +151,6 @@ instance ToJSON InsertOrder where
     BeforeParent -> String "before_parent"
     AfterParent  -> String "after_parent"
 
--- should this be parameterized by both the source and the destination backend?
-data RelInfo (b :: BackendType)
-  = RelInfo
-  { riName        :: !RelName
-  , riType        :: !RelType
-  , riMapping     :: !(HashMap (Column b) (Column b))
-  , riRTable      :: !(TableName b)
-  , riIsManual    :: !Bool
-  , riIsNullable  :: !Bool
-  , riInsertOrder :: !InsertOrder
-  } deriving (Generic)
-deriving instance Backend b => Show (RelInfo b)
-deriving instance Backend b => Eq   (RelInfo b)
-instance Backend b => NFData (RelInfo b)
-instance Backend b => Cacheable (RelInfo b)
-instance Backend b => Hashable (RelInfo b)
-instance Backend b => FromJSON (RelInfo b) where
-  parseJSON = genericParseJSON hasuraJSON
-instance Backend b => ToJSON (RelInfo b) where
-  toJSON = genericToJSON hasuraJSON
 
 -- | Postgres OIDs. <https://www.postgresql.org/docs/12/datatype-oid.html>
 newtype OID = OID { unOID :: Int }

server/src-lib/Hasura/RQL/Types/Relationship.hs

@@ -265,7 +265,7 @@ data RelInfo (b :: BackendType)
   , riMapping     :: !(HashMap (Column b) (Column b))
   , riRTable      :: !(TableName b)
   , riIsManual    :: !Bool
-  , riIsNullable  :: !Bool
+  , riIsNullable  :: !Nullable
   , riInsertOrder :: !InsertOrder
   } deriving (Generic)
 deriving instance Backend b => Show (RelInfo b)
@@ -280,5 +280,24 @@ instance (Backend b) => FromJSON (RelInfo b) where
 instance (Backend b) => ToJSON (RelInfo b) where
   toJSON = genericToJSON hasuraJSON
 
+data Nullable = Nullable | NotNullable
+  deriving (Eq, Show, Generic)
+
+instance NFData Nullable
+instance Cacheable Nullable
+instance Hashable Nullable
+
+boolToNullable :: Bool -> Nullable
+boolToNullable True  = Nullable
+boolToNullable False = NotNullable
+
+instance FromJSON Nullable where
+  parseJSON = fmap boolToNullable . parseJSON
+
+instance ToJSON Nullable where
+  toJSON = toJSON . \case
+    Nullable    -> True
+    NotNullable -> False
+
 fromRel :: RelName -> FieldName
 fromRel = FieldName . relNameToTxt