Validate non-nullable values inside lists

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to
   validation traverser calls it on all list items.
 - `valuesOfCorrectTypeRule` doesn't check objects recursively since the
   validation traverser calls it on all object properties.
+- Validation of non-nullable values inside lists.
 
 ### Changed
 - `AST.Document.Value.List` and `AST.Document.ConstValue.ConstList` contain

src/Language/GraphQL/Validate.hs

@@ -314,9 +314,6 @@ constValue (Validation.ValueRule _ rule) valueType = go valueType
     go inputObjectType value'@(Full.Node (Full.ConstObject fields) _)
         = foldMap (forEach inputObjectType) (Seq.fromList fields)
         |> rule inputObjectType value'
-    go listType value'@(Full.Node (Full.ConstList values) _location)
-        = embedListLocation go listType values
-        |> rule listType value'
     go anotherValue value' = pure $ rule anotherValue value'
     forEach inputObjectType Full.ObjectField{value = value', ..} =
         go (valueTypeByName name inputObjectType) value'
@@ -420,19 +417,6 @@ argument rule argumentType (Full.Argument _ value' _) =
   where
     valueType (In.Argument _ valueType' _) = valueType'
 
--- Applies a validation rule to each list value and merges returned errors.
-embedListLocation :: forall a m
-    . (Maybe In.Type -> Full.Node a -> Seq m)
-    -> Maybe In.Type
-    -> [Full.Node a]
-    -> Seq m
-embedListLocation go listType
-    = foldMap (go $ valueTypeFromList listType) 
-    . Seq.fromList
-  where
-    valueTypeFromList (Just (In.ListBaseType baseType)) = Just baseType
-    valueTypeFromList _ = Nothing
-
 value :: forall m
     . Validation.Rule m
     -> Maybe In.Type
@@ -443,9 +427,6 @@ value (Validation.ValueRule rule _) valueType = go valueType
     go inputObjectType value'@(Full.Node (Full.Object fields) _)
         = foldMap (forEach inputObjectType) (Seq.fromList fields)
         |> rule inputObjectType value'
-    go listType value'@(Full.Node (Full.List values) _location)
-        = embedListLocation go listType values
-        |> rule listType value'
     go anotherValue value' = pure $ rule anotherValue value'
     forEach inputObjectType Full.ObjectField{value = value', ..} =
         go (valueTypeByName name inputObjectType) value'

src/Language/GraphQL/Validate/Rules.hs

@@ -1502,15 +1502,6 @@ variablesInAllowedPositionRule = OperationDefinitionRule $ \case
     hasNonNullVariableDefaultValue (Just (Full.Node Full.ConstNull _)) = False
     hasNonNullVariableDefaultValue Nothing = False
     hasNonNullVariableDefaultValue _ = True
-    unwrapInType (In.NonNullScalarType nonNullType) =
-        Just $ In.NamedScalarType nonNullType
-    unwrapInType (In.NonNullEnumType nonNullType) =
-        Just $ In.NamedEnumType nonNullType
-    unwrapInType (In.NonNullInputObjectType nonNullType) =
-        Just $ In.NamedInputObjectType nonNullType
-    unwrapInType (In.NonNullListType nonNullType) =
-        Just $ In.ListType nonNullType
-    unwrapInType _ = Nothing
     makeError variableDefinition expectedType =
         let Full.VariableDefinition variableName variableType _ location' =
                 variableDefinition
@@ -1527,6 +1518,17 @@ variablesInAllowedPositionRule = OperationDefinitionRule $ \case
             , locations = [location']
             }
 
+unwrapInType :: In.Type -> Maybe In.Type
+unwrapInType (In.NonNullScalarType nonNullType) =
+    Just $ In.NamedScalarType nonNullType
+unwrapInType (In.NonNullEnumType nonNullType) =
+    Just $ In.NamedEnumType nonNullType
+unwrapInType (In.NonNullInputObjectType nonNullType) =
+    Just $ In.NamedInputObjectType nonNullType
+unwrapInType (In.NonNullListType nonNullType) =
+    Just $ In.ListType nonNullType
+unwrapInType _ = Nothing
+
 -- | Literal values must be compatible with the type expected in the position
 -- they are found as per the coercion rules.
 --
@@ -1586,8 +1588,8 @@ valuesOfCorrectTypeRule = ValueRule go constGo
         | In.InputObjectType{}  <- objectType
         , Full.ConstObject{} <- node = mempty
     check (In.ListBaseType listType) constValue@Full.Node{ .. }
-        -- Skip, lists are checked recursively by the validation traverser.
-        | Full.ConstList{} <- node = mempty
+        | Full.ConstList values <- node =
+            foldMap (checkNull listType) values
         | otherwise = check listType constValue
     check inputType Full.Node{ .. } = pure $ Error
         { message = concat
@@ -1599,3 +1601,20 @@ valuesOfCorrectTypeRule = ValueRule go constGo
             ]
         , locations = [location]
         }
+    checkNull inputType constValue =
+        let checkResult = check inputType constValue
+         in case null checkResult of
+            True
+                | Just unwrappedType <- unwrapInType inputType
+                , Full.Node{ node = Full.ConstNull, .. } <- constValue ->
+                    pure $ Error
+                        { message = concat
+                            [ "List of non-null values of type \""
+                            , show unwrappedType
+                            , "\" cannot contain null values."
+                            ]
+                        , locations = [location]
+                        }
+                | otherwise -> mempty
+            _ -> checkResult
+

stack.yaml

@@ -1,4 +1,4 @@
-resolver: lts-17.9
+resolver: lts-17.10
 
 packages:
 - .

tests/Language/GraphQL/Validate/RulesSpec.hs

@@ -847,7 +847,7 @@ spec =
                         }
                  in validate queryString `shouldBe` [expected]
 
-        context "providedRequiredArgumentsRule" $
+        context "providedRequiredArgumentsRule" $ do
             it "checks for (non-)nullable arguments" $
                 let queryString = [r|
                   {
@@ -944,3 +944,19 @@ spec =
                         , locations = [AST.Location 3 46]
                         }
                  in validate queryString `shouldBe` [expected]
+
+            it "checks for required list members" $
+                let queryString = [r|
+                  {
+                    cat {
+                      doesKnowCommands(catCommands: [null])
+                    }
+                  }
+                |]
+                    expected = Error
+                        { message =
+                            "List of non-null values of type \"CatCommand\" \
+                            \cannot contain null values."
+                        , locations = [AST.Location 4 54]
+                        }
+                 in validate queryString `shouldBe` [expected]