Merge pull request #223 from graphql-go/titanous/fix-nil-crashes

go-fuzz nil panic fixes

rules.go

@@ -214,30 +214,38 @@ func FieldsOnCorrectTypeRule(context *ValidationContext) *ValidationRuleInstance
 					var result interface{}
 					if node, ok := p.Node.(*ast.Field); ok {
 						ttype := context.ParentType()
+						if ttype == nil {
+							return action, result
+						}
+						if t, ok := ttype.(*Object); ok && t == nil {
+							return action, result
+						}
+						if t, ok := ttype.(*Interface); ok && t == nil {
+							return action, result
+						}
+						if t, ok := ttype.(*Union); ok && t == nil {
+							return action, result
+						}
+						fieldDef := context.FieldDef()
+						if fieldDef == nil {
+							// This field doesn't exist, lets look for suggestions.
+							nodeName := ""
+							if node.Name != nil {
+								nodeName = node.Name.Value
+							}
+							// First determine if there are any suggested types to condition on.
+							suggestedTypeNames := getSuggestedTypeNames(context.Schema(), ttype, nodeName)
 
-						if ttype != nil {
-							fieldDef := context.FieldDef()
-							if fieldDef == nil {
-								// This field doesn't exist, lets look for suggestions.
-								nodeName := ""
-								if node.Name != nil {
-									nodeName = node.Name.Value
-								}
-								// First determine if there are any suggested types to condition on.
-								suggestedTypeNames := getSuggestedTypeNames(context.Schema(), ttype, nodeName)
-
-								// If there are no suggested types, then perhaps this was a typo?
-								suggestedFieldNames := []string{}
-								if len(suggestedTypeNames) == 0 {
-									suggestedFieldNames = getSuggestedFieldNames(context.Schema(), ttype, nodeName)
-								}
-
-								reportError(
-									context,
-									UndefinedFieldMessage(nodeName, ttype.Name(), suggestedTypeNames, suggestedFieldNames),
-									[]ast.Node{node},
-								)
+							// If there are no suggested types, then perhaps this was a typo?
+							suggestedFieldNames := []string{}
+							if len(suggestedTypeNames) == 0 {
+								suggestedFieldNames = getSuggestedFieldNames(context.Schema(), ttype, nodeName)
 							}
+							reportError(
+								context,
+								UndefinedFieldMessage(nodeName, ttype.Name(), suggestedTypeNames, suggestedFieldNames),
+								[]ast.Node{node},
+							)
 						}
 					}
 					return action, result
@@ -1717,6 +1725,9 @@ func VariablesInAllowedPositionRule(context *ValidationContext) *ValidationRuleI
 func isValidLiteralValue(ttype Input, valueAST ast.Value) (bool, []string) {
 	// A value must be provided if the type is non-null.
 	if ttype, ok := ttype.(*NonNull); ok {
+		if e := ttype.Error(); e != nil {
+			return false, []string{e.Error()}
+		}
 		if valueAST == nil {
 			if ttype.OfType.Name() != "" {
 				return false, []string{fmt.Sprintf(`Expected "%v!", found null.`, ttype.OfType.Name())}

rules_default_values_of_correct_type_test.go

@@ -101,3 +101,7 @@ func TestValidate_VariableDefaultValuesOfCorrectType_ListVariablesWithInvalidIte
 				2, 40),
 		})
 }
+
+func TestValidate_VariableDefaultValuesOfCorrectType_InvalidNonNull(t *testing.T) {
+	testutil.ExpectPassesRule(t, graphql.DefaultValuesOfCorrectTypeRule, `query($g:e!){a}`)
+}

rules_fields_on_correct_type_test.go

@@ -236,3 +236,7 @@ func TestValidate_FieldsOnCorrectTypeErrorMessage_LimitLotsOfFieldSuggestions(t
 		t.Fatalf("Unexpected message, expected: %v, got %v", expected, message)
 	}
 }
+
+func TestValidate_FieldsOnCorrectType_NilCrash(t *testing.T) {
+	testutil.ExpectPassesRule(t, graphql.FieldsOnCorrectTypeRule, `mutation{o}`)
+}

rules_overlapping_fields_can_be_merged.go

@@ -467,10 +467,10 @@ func (rule *overlappingFieldsCanBeMergedRule) getFieldsAndFragmentNames(parentTy
 					fieldName = selection.Name.Value
 				}
 				var fieldDef *FieldDefinition
-				if parentType, ok := parentType.(*Object); ok {
+				if parentType, ok := parentType.(*Object); ok && parentType != nil {
 					fieldDef, _ = parentType.Fields()[fieldName]
 				}
-				if parentType, ok := parentType.(*Interface); ok {
+				if parentType, ok := parentType.(*Interface); ok && parentType != nil {
 					fieldDef, _ = parentType.Fields()[fieldName]
 				}
 

rules_overlapping_fields_can_be_merged_test.go

@@ -888,3 +888,7 @@ func TestValidate_OverlappingFieldsCanBeMerged_ReturnTypesMustBeUnambiguous_Igno
         }
     `)
 }
+
+func TestValidate_OverlappingFieldsCanBeMerged_NilCrash(t *testing.T) {
+	testutil.ExpectPassesRule(t, graphql.OverlappingFieldsCanBeMergedRule, `subscription {e}`)
+}

type_info.go

@@ -252,14 +252,14 @@ func DefaultTypeInfoFieldDef(schema *Schema, parentType Type, fieldAST *ast.Fiel
 		schema.QueryType() == parentType {
 		return TypeMetaFieldDef
 	}
-	if name == TypeNameMetaFieldDef.Name {
-		if _, ok := parentType.(*Object); ok && parentType != nil {
+	if name == TypeNameMetaFieldDef.Name && parentType != nil {
+		if t, ok := parentType.(*Object); ok && t != nil {
 			return TypeNameMetaFieldDef
 		}
-		if _, ok := parentType.(*Interface); ok && parentType != nil {
+		if t, ok := parentType.(*Interface); ok && t != nil {
 			return TypeNameMetaFieldDef
 		}
-		if _, ok := parentType.(*Union); ok && parentType != nil {
+		if t, ok := parentType.(*Union); ok && t != nil {
 			return TypeNameMetaFieldDef
 		}
 	}