Allow null scalars

Author: jennybuckley

typed/helpers.go

@@ -129,6 +129,9 @@ func (ef errorFormatter) validateScalar(t schema.Scalar, v *value.Value, prefix
 	if v == nil {
 		return nil
 	}
+	if v.Null {
+		return nil
+	}
 	switch t {
 	case schema.Numeric:
 		if v.FloatValue == nil && v.IntValue == nil {

typed/validate_test.go

@@ -53,12 +53,12 @@ var validationCases = []validationTestCase{{
 		`{"key":"foo"}`,
 		`{"key":"foo","value":true}`,
 		`{"key":"foo","value":true}`,
+		`{"key":null}`,
 	},
 	invalidObjects: []typed.YAMLObject{
 		`{"key":true,"value":1}`,
 		`{"key":1,"value":{}}`,
 		`{"key":false,"value":null}`,
-		`{"key":null}`,
 		`{"key":[1, 2]}`,
 		`{"key":{"foo":true}}`,
 	},
@@ -98,28 +98,28 @@ var validationCases = []validationTestCase{{
           elementRelationship: associative
 `,
 	validObjects: []typed.YAMLObject{
+		`{"numeric":null}`,
 		`{"numeric":1}`,
 		`{"numeric":3.14159}`,
+		`{"string":null}`,
 		`{"string":"aoeu"}`,
+		`{"bool":null}`,
 		`{"bool":true}`,
 		`{"bool":false}`,
 		`{"setStr":["a","b","c"]}`,
 		`{"setBool":[true,false]}`,
 		`{"setNumeric":[1,2,3,3.14159]}`,
 	},
 	invalidObjects: []typed.YAMLObject{
-		`{"numeric":null}`,
 		`{"numeric":["foo"]}`,
 		`{"numeric":{"a":1}}`,
 		`{"numeric":"foo"}`,
 		`{"numeric":true}`,
-		`{"string":null}`,
 		`{"string":1}`,
 		`{"string":3.5}`,
 		`{"string":true}`,
 		`{"string":{"a":1}}`,
 		`{"string":["foo"]}`,
-		`{"bool":null}`,
 		`{"bool":1}`,
 		`{"bool":3.5}`,
 		`{"bool":"aoeu"}`,