support for @deprecated directive on fields (fixes #64)

graphql_test.go

@@ -462,6 +462,66 @@ func TestIncludeDirective(t *testing.T) {
 	})
 }
 
+type testDeprecatedDirectiveResolver struct{}
+
+func (r *testDeprecatedDirectiveResolver) A() int32 {
+	return 0
+}
+
+func (r *testDeprecatedDirectiveResolver) B() int32 {
+	return 0
+}
+
+func (r *testDeprecatedDirectiveResolver) C() int32 {
+	return 0
+}
+
+func TestDeprecatedDirective(t *testing.T) {
+	graphql.RunTests(t, []*graphql.Test{
+		{
+			Schema: graphql.MustParseSchema(`
+				schema {
+					query: Query
+				}
+
+				type Query {
+					a: Int!
+					b: Int! @deprecated
+					c: Int! @deprecated(reason: "We don't like it")
+				}
+			`, &testDeprecatedDirectiveResolver{}),
+			Query: `
+				{
+					__type(name: "Query") {
+						fields {
+							name
+						}
+						allFields: fields(includeDeprecated: true) {
+							name
+							isDeprecated
+							deprecationReason
+						}
+					}
+				}
+			`,
+			ExpectedResult: `
+				{
+					"__type": {
+						"fields": [
+							{ "name": "a" }
+						],
+						"allFields": [
+							{ "name": "a", "isDeprecated": false, "deprecationReason": null },
+							{ "name": "b", "isDeprecated": true, "deprecationReason": "No longer supported" },
+							{ "name": "c", "isDeprecated": true, "deprecationReason": "We don't like it" }
+						]
+					}
+				}
+			`,
+		},
+	})
+}
+
 func TestInlineFragments(t *testing.T) {
 	graphql.RunTests(t, []*graphql.Test{
 		{
@@ -1134,6 +1194,24 @@ func TestIntrospection(t *testing.T) {
 				{
 						"__schema": {
 							"directives": [
+								{
+									"name": "deprecated",
+									"description": "Marks an element of a GraphQL schema as no longer supported.",
+									"locations": [
+										"FIELD_DEFINITION",
+										"ENUM_VALUE"
+									],
+									"args": [
+										{
+											"name": "reason",
+											"description": "Explains why this element was deprecated, usually also including a suggestion\nfor how to access supported similar data. Formatted in\n[Markdown](https://daringfireball.net/projects/markdown/).",
+											"type": {
+												"kind": "SCALAR",
+												"ofType": null
+											}
+										}
+									]
+								},
 								{
 									"name": "include",
 									"description": "Directs the executor to include this field or fragment only when the ` + "`" + `if` + "`" + ` argument is true.",

internal/common/directive.go

@@ -11,7 +11,7 @@ func ParseDirectives(l *lexer.Lexer) map[string]DirectiveArgs {
 	for l.Peek() == '@' {
 		l.ConsumeToken('@')
 		name := l.ConsumeIdent()
-		var args DirectiveArgs
+		args := make(DirectiveArgs)
 		if l.Peek() == '(' {
 			args = ParseArguments(l)
 		}

internal/schema/meta.go

@@ -38,6 +38,14 @@ var metaSrc = `
 		if: Boolean!
 	) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
+	# Marks an element of a GraphQL schema as no longer supported.
+	directive @deprecated(
+		# Explains why this element was deprecated, usually also including a suggestion
+		# for how to access supported similar data. Formatted in
+		# [Markdown](https://daringfireball.net/projects/markdown/).
+		reason: String = "No longer supported"
+	) on FIELD_DEFINITION | ENUM_VALUE
+
 	# A Directive provides a way to describe alternate runtime execution and type validation behavior in a GraphQL document.
 	#
 	# In some cases, you need to provide options to alter GraphQL's execution behavior

internal/schema/schema.go

@@ -115,10 +115,11 @@ func (t *Enum) Description() string        { return t.Desc }
 func (t *InputObject) Description() string { return t.Desc }
 
 type Field struct {
-	Name string
-	Args common.InputMap
-	Type common.Type
-	Desc string
+	Name       string
+	Args       common.InputMap
+	Type       common.Type
+	Directives map[string]common.DirectiveArgs
+	Desc       string
 }
 
 func New() *Schema {
@@ -238,6 +239,22 @@ func resolveField(s *Schema, f *Field) error {
 		return err
 	}
 	f.Type = t
+	for name, args := range f.Directives {
+		d, ok := s.Directives[name]
+		if !ok {
+			return errors.Errorf("directive %q not found", name)
+		}
+		for argName := range args {
+			if _, ok := d.Args[argName]; !ok {
+				return errors.Errorf("invalid argument %q for directive %q", argName, name)
+			}
+		}
+		for argName, arg := range d.Args {
+			if _, ok := args[argName]; !ok {
+				args[argName] = arg.Default
+			}
+		}
+	}
 	return resolveInputObject(s, &f.Args)
 }
 
@@ -410,6 +427,7 @@ func parseFields(l *lexer.Lexer) (map[string]*Field, []string) {
 		}
 		l.ConsumeToken(':')
 		f.Type = common.ParseType(l)
+		f.Directives = common.ParseDirectives(l)
 		fields[f.Name] = f
 		fieldOrder = append(fieldOrder, f.Name)
 	}

introspection/introspection.go

@@ -115,9 +115,12 @@ func (r *Type) Fields(args *struct{ IncludeDeprecated bool }) *[]*Field {
 		return nil
 	}
 
-	l := make([]*Field, len(fieldOrder))
-	for i, name := range fieldOrder {
-		l[i] = &Field{fields[name]}
+	var l []*Field
+	for _, name := range fieldOrder {
+		f := fields[name]
+		if _, ok := f.Directives["deprecated"]; !ok || args.IncludeDeprecated {
+			l = append(l, &Field{f})
+		}
 	}
 	return &l
 }
@@ -218,11 +221,17 @@ func (r *Field) Type() *Type {
 }
 
 func (r *Field) IsDeprecated() bool {
-	return false
+	_, ok := r.field.Directives["deprecated"]
+	return ok
 }
 
 func (r *Field) DeprecationReason() *string {
-	return nil
+	args, ok := r.field.Directives["deprecated"]
+	if !ok {
+		return nil
+	}
+	reason := args["reason"].(string)
+	return &reason
 }
 
 type InputValue struct {