helper/schema: one of Optional, Required, Computed must be set

helper/schema/schema.go

@@ -78,6 +78,10 @@ type SchemaSetFunc func(interface{}) int
 // to be stored in the state.
 type SchemaStateFunc func(interface{}) string
 
+func (s *Schema) GoString() string {
+	return fmt.Sprintf("*%#v", *s)
+}
+
 func (s *Schema) finalizeDiff(
 	d *terraform.ResourceAttrDiff) *terraform.ResourceAttrDiff {
 	if d == nil {
@@ -184,6 +188,10 @@ func (m schemaMap) InternalValidate() error {
 			return fmt.Errorf("%s: Cannot be both Required and Computed", k)
 		}
 
+		if !v.Required && !v.Optional && !v.Computed {
+			return fmt.Errorf("%s: One of optional, required, or computed must be set", k)
+		}
+
 		if len(v.ComputedWhen) > 0 && !v.Computed {
 			return fmt.Errorf("%s: ComputedWhen can only be set with Computed", k)
 		}

helper/schema/schema_test.go

@@ -780,6 +780,16 @@ func TestSchemaMap_InternalValidate(t *testing.T) {
 			true,
 		},
 
+		// No optional and no required
+		{
+			map[string]*Schema{
+				"foo": &Schema{
+					Type: TypeInt,
+				},
+			},
+			true,
+		},
+
 		// Missing Type
 		{
 			map[string]*Schema{
@@ -828,6 +838,7 @@ func TestSchemaMap_InternalValidate(t *testing.T) {
 			map[string]*Schema{
 				"foo": &Schema{
 					Type:     TypeList,
+					Optional: true,
 					Elem: &Schema{
 						Type:     TypeInt,
 						Computed: true,
@@ -844,6 +855,7 @@ func TestSchemaMap_InternalValidate(t *testing.T) {
 					Type:     TypeList,
 					Elem:     &Schema{Type: TypeInt},
 					Set:      func(interface{}) int { return 0 },
+					Optional: true,
 				},
 			},
 			true,
@@ -855,6 +867,7 @@ func TestSchemaMap_InternalValidate(t *testing.T) {
 				"foo": &Schema{
 					Type:     TypeSet,
 					Elem:     &Schema{Type: TypeInt},
+					Optional: true,
 				},
 			},
 			true,
@@ -877,6 +890,7 @@ func TestSchemaMap_InternalValidate(t *testing.T) {
 			map[string]*Schema{
 				"foo": &Schema{
 					Type:     TypeList,
+					Optional: true,
 					Elem: &Resource{
 						Schema: map[string]*Schema{
 							"foo": new(Schema),
@@ -892,10 +906,12 @@ func TestSchemaMap_InternalValidate(t *testing.T) {
 			map[string]*Schema{
 				"foo": &Schema{
 					Type:     TypeList,
+					Optional: true,
 					Elem: &Resource{
 						Schema: map[string]*Schema{
 							"foo": &Schema{
 								Type:     TypeInt,
+								Optional: true,
 							},
 						},
 					},
@@ -908,7 +924,7 @@ func TestSchemaMap_InternalValidate(t *testing.T) {
 	for i, tc := range cases {
 		err := schemaMap(tc.In).InternalValidate()
 		if (err != nil) != tc.Err {
-			t.Fatalf("%d: bad: %s", i, err)
+			t.Fatalf("%d: bad: %s\n\n%#v", i, err, tc.In)
 		}
 	}