redo type naming

README.md

@@ -53,7 +53,9 @@ For a complete working example, see `example/`.
 
 `go test ./...` tests code generation.  (This is run by GitHub Actions.)
 
-`make example` tests that everything wires up to a real API correctly.
+Most of the tests are snapshot-based; they use the schema, queries, and snapshots in `generate/testdata`.  The schema is in `schema.graphql`; the queries are in `TestName.graphql`.  The test by default asserts that the output of the generator matches the snapshot `TestName.graphql.go`.  To update the snapshots, run with `UPDATE_SNAPSHOTS=1`; it will fail the tests and print the diffs, but regenerate the snapshots.  Make sure to check that the output is sensible!
+
+`make example` rebuilds the example, and tests that everything wires up to a real API correctly.
 
 TODO(benkraft): Figure out how to get GitHub Actions to run the example -- it needs a token.
 
@@ -67,7 +69,6 @@ See [DESIGN.md](DESIGN.md) for documentation of major design decisions in this l
 (+) denotes things we further need before recommending anyone else use this in prod
 
 Generated code:
-- (*) update type naming for new scheme
 - (*) remove pointers for optionality (or put behind flag)
 - redo support for interfaces, unions, fragments (see DESIGN)
 - (optional) collapsing -- should be able to have `mutation { myMutation { error { code } } }` just return `(code string, err error)`
@@ -77,6 +78,7 @@ Config options:
 - (+) fix up context/client wiring (see DESIGN)
 - get schema via HTTP (perhaps even via GraphQL introspection)
 - send hash rather than full query
+- whether names should be exported
 
 Other:
 - (*) error-checking/validation/etc. everywhere
@@ -84,3 +86,4 @@ Other:
 - (+) more tests
 - (+) documentation
 - custom scalar types
+- allow mapping a custom type to a particular val (if you want to use a named type for some string, say)

example/generated.go

@@ -8,24 +8,24 @@ import (
 	"github.com/Khan/genql/graphql"
 )
 
-type User struct {
-	MyName *string
+type GetUserResponse struct {
+	User *GetUserUser `json:"user"`
 }
 
-type User1 struct {
+type GetUserUser struct {
 	TheirName *string `json:"theirName"`
 }
 
-type getUserResponse struct {
-	User *User1 `json:"user"`
+type GetViewerResponse struct {
+	Viewer GetViewerViewerUser `json:"viewer"`
 }
 
-type getViewerResponse struct {
-	Viewer User `json:"viewer"`
+type GetViewerViewerUser struct {
+	MyName *string
 }
 
-func getViewer(ctx context.Context, client *graphql.Client) (*getViewerResponse, error) {
-	var retval getViewerResponse
+func getViewer(ctx context.Context, client *graphql.Client) (*GetViewerResponse, error) {
+	var retval GetViewerResponse
 	err := client.MakeRequest(ctx, `
 query getViewer {
 	viewer {
@@ -37,12 +37,12 @@ query getViewer {
 }
 
 // getUser gets the given user's name from their username.
-func getUser(ctx context.Context, client *graphql.Client, login string) (*getUserResponse, error) {
+func getUser(ctx context.Context, client *graphql.Client, login string) (*GetUserResponse, error) {
 	variables := map[string]interface{}{
 		"Login": login,
 	}
 
-	var retval getUserResponse
+	var retval GetUserResponse
 	err := client.MakeRequest(ctx, `
 query getUser ($Login: String!) {
 	user(login: $Login) {

generate/generate_test.go

@@ -35,12 +35,6 @@ func gofmt(src string) (string, error) {
 }
 
 func TestGenerate(t *testing.T) {
-	// This test uses the schema, queries, and expected-output in ./testdata.
-	// The schema is in schema.graphql.  The queries are in TestName.graphql;
-	// the test asserts that the output of the generator for that query is
-	// matches TestName.graphql.go.  To update the expected output, run the
-	// tests with UPDATE_SNAPSHOTS=1 (they will still fail, but also do the
-	// update, so you can see which updates were made).
 	update := (os.Getenv("UPDATE_SNAPSHOTS") == "1")
 
 	files, err := ioutil.ReadDir(dataDir)
@@ -74,12 +68,14 @@ func TestGenerate(t *testing.T) {
 				t.Errorf("got:\n%v\nwant:\n%v\n", string(goCode), expectedGoCode)
 				if update {
 					t.Log("Updating testdata dir to match")
-					err = ioutil.WriteFile(filepath.Join(dataDir, goFilename), goCode, 0644)
+					err = ioutil.WriteFile(filepath.Join(dataDir, goFilename), goCode, 0o644)
 					if err != nil {
 						t.Errorf("Unable to update testdata dir: %v", err)
 					}
 				}
 			}
+
+			// TODO(benkraft): Also check that the code at least builds!
 		})
 	}
 }

generate/testdata/InputObject.graphql.go

@@ -9,28 +9,28 @@ import (
 )
 
 type InputObjectQueryResponse struct {
-	User *User `json:"user"`
+	User *InputObjectQueryUser `json:"user"`
 }
 
-type Role string
-
-const (
-	StudentRole Role = "STUDENT"
-	TeacherRole Role = "TEACHER"
-)
-
-type User struct {
+type InputObjectQueryUser struct {
 	Id string `json:"id"`
 }
 
 type UserQueryInput struct {
-	Email *string   `json:"email"`
-	Name  *string   `json:"name"`
-	Id    *string   `json:"id"`
-	Role  *Role     `json:"role"`
-	Names []*string `json:"names"`
+	Email *string             `json:"email"`
+	Name  *string             `json:"name"`
+	Id    *string             `json:"id"`
+	Role  *UserQueryInputRole `json:"role"`
+	Names []*string           `json:"names"`
 }
 
+type UserQueryInputRole string
+
+const (
+	UserQueryInputRoleStudent UserQueryInputRole = "STUDENT"
+	UserQueryInputRoleTeacher UserQueryInputRole = "TEACHER"
+)
+
 func InputObjectQuery(client *graphql.Client, query *UserQueryInput) (*InputObjectQueryResponse, error) {
 	variables := map[string]interface{}{
 		"query": query,

generate/testdata/InterfaceNoFragments.graphql.go

@@ -8,35 +8,24 @@ import (
 	"github.com/Khan/genql/graphql"
 )
 
-type Article struct {
-	Id   string `json:"id"`
-	Name string `json:"name"`
-}
-
-func (v Article) implementsGraphQLInterfaceContent() {}
-
-type Content interface {
-	implementsGraphQLInterfaceContent()
-}
-
 type InterfaceNoFragmentsQueryResponse struct {
-	Root Topic `json:"root"`
+	Root InterfaceNoFragmentsQueryRootTopic `json:"root"`
 }
 
-type Topic struct {
-	Id       string    `json:"id"`
-	Name     string    `json:"name"`
-	Children []Content `json:"-"`
+type InterfaceNoFragmentsQueryRootTopic struct {
+	Id       string                                              `json:"id"`
+	Name     string                                              `json:"name"`
+	Children []InterfaceNoFragmentsQueryRootTopicChildrenContent `json:"-"`
 }
 
-func (v *Topic) UnmarshalJSON(b []byte) error {
+func (v *InterfaceNoFragmentsQueryRootTopic) UnmarshalJSON(b []byte) error {
 	var firstPass struct {
-		*Topic
+		*InterfaceNoFragmentsQueryRootTopic
 		Children json.RawMessage `json:"children"`
 	}
-	firstPass.Topic = v
+	firstPass.InterfaceNoFragmentsQueryRootTopic = v
 
-	err := json.Unmarshal(b, &typenames)
+	err := json.Unmarshal(b, &firstPass)
 	if err != nil {
 		return err
 	}
@@ -51,17 +40,20 @@ func (v *Topic) UnmarshalJSON(b []byte) error {
 	switch tn.TypeName {
 
 	case "Article":
-		v.Children = Article{}
+
+		v.Children = InterfaceNoFragmentsQueryRootTopicChildrenArticle{}
 		err = json.Unmarshal(
 			firstPass.Children, &v.Children)
 
 	case "Video":
-		v.Children = Video{}
+
+		v.Children = InterfaceNoFragmentsQueryRootTopicChildrenVideo{}
 		err = json.Unmarshal(
 			firstPass.Children, &v.Children)
 
 	case "Topic":
-		v.Children = Topic{}
+
+		v.Children = InterfaceNoFragmentsQueryRootTopicChildrenTopic{}
 		err = json.Unmarshal(
 			firstPass.Children, &v.Children)
 
@@ -70,14 +62,36 @@ func (v *Topic) UnmarshalJSON(b []byte) error {
 		return err
 	}
 
+	return nil
 }
 
-type Video struct {
+type InterfaceNoFragmentsQueryRootTopicChildrenArticle struct {
 	Id   string `json:"id"`
 	Name string `json:"name"`
 }
 
-func (v Video) implementsGraphQLInterfaceContent() {}
+func (v InterfaceNoFragmentsQueryRootTopicChildrenArticle) implementsGraphQLInterfaceInterfaceNoFragmentsQueryRootTopicChildrenContent() {
+}
+
+type InterfaceNoFragmentsQueryRootTopicChildrenContent interface {
+	implementsGraphQLInterfaceInterfaceNoFragmentsQueryRootTopicChildrenContent()
+}
+
+type InterfaceNoFragmentsQueryRootTopicChildrenTopic struct {
+	Id   string `json:"id"`
+	Name string `json:"name"`
+}
+
+func (v InterfaceNoFragmentsQueryRootTopicChildrenTopic) implementsGraphQLInterfaceInterfaceNoFragmentsQueryRootTopicChildrenContent() {
+}
+
+type InterfaceNoFragmentsQueryRootTopicChildrenVideo struct {
+	Id   string `json:"id"`
+	Name string `json:"name"`
+}
+
+func (v InterfaceNoFragmentsQueryRootTopicChildrenVideo) implementsGraphQLInterfaceInterfaceNoFragmentsQueryRootTopicChildrenContent() {
+}
 
 func InterfaceNoFragmentsQuery(client *graphql.Client) (*InterfaceNoFragmentsQueryResponse, error) {
 	var retval InterfaceNoFragmentsQueryResponse

generate/testdata/ListInput.graphql.go

@@ -9,10 +9,10 @@ import (
 )
 
 type ListInputQueryResponse struct {
-	User *User `json:"user"`
+	User *ListInputQueryUser `json:"user"`
 }
 
-type User struct {
+type ListInputQueryUser struct {
 	Id string `json:"id"`
 }
 

generate/testdata/QueryWithAlias.graphql.go

@@ -9,10 +9,10 @@ import (
 )
 
 type QueryWithAliasResponse struct {
-	User *User
+	User *QueryWithAliasUser
 }
 
-type User struct {
+type QueryWithAliasUser struct {
 	ID string
 }
 

generate/testdata/QueryWithDoubleAlias.graphql.go

@@ -9,10 +9,10 @@ import (
 )
 
 type QueryWithDoubleAliasResponse struct {
-	User *User `json:"user"`
+	User *QueryWithDoubleAliasUser `json:"user"`
 }
 
-type User struct {
+type QueryWithDoubleAliasUser struct {
 	ID     string
 	AlsoID string
 }

generate/testdata/QueryWithEnums.graphql.go

@@ -9,20 +9,20 @@ import (
 )
 
 type QueryWithEnumsResponse struct {
-	User *User `json:"user"`
+	User *QueryWithEnumsUser `json:"user"`
 }
 
-type Role string
+type QueryWithEnumsUser struct {
+	Roles []QueryWithEnumsUserRolesRole `json:"roles"`
+}
+
+type QueryWithEnumsUserRolesRole string
 
 const (
-	StudentRole Role = "STUDENT"
-	TeacherRole Role = "TEACHER"
+	QueryWithEnumsUserRolesRoleStudent QueryWithEnumsUserRolesRole = "STUDENT"
+	QueryWithEnumsUserRolesRoleTeacher QueryWithEnumsUserRolesRole = "TEACHER"
 )
 
-type User struct {
-	Roles []Role `json:"roles"`
-}
-
 func QueryWithEnums(client *graphql.Client) (*QueryWithEnumsResponse, error) {
 	var retval QueryWithEnumsResponse
 	err := client.MakeRequest(context.Background(), `

generate/testdata/QueryWithSlices.graphql.go

@@ -9,10 +9,10 @@ import (
 )
 
 type QueryWithSlicesResponse struct {
-	User *User `json:"user"`
+	User *QueryWithSlicesUser `json:"user"`
 }
 
-type User struct {
+type QueryWithSlicesUser struct {
 	Emails                []string  `json:"emails"`
 	EmailsOrNull          []string  `json:"emailsOrNull"`
 	EmailsWithNulls       []*string `json:"emailsWithNulls"`

generate/testdata/QueryWithStructs.graphql.go

@@ -8,19 +8,19 @@ import (
 	"github.com/Khan/genql/graphql"
 )
 
-type AuthMethod struct {
+type QueryWithStructsResponse struct {
+	User *QueryWithStructsUser `json:"user"`
+}
+
+type QueryWithStructsUser struct {
+	AuthMethods []QueryWithStructsUserAuthMethodsAuthMethod `json:"authMethods"`
+}
+
+type QueryWithStructsUserAuthMethodsAuthMethod struct {
 	Provider *string `json:"provider"`
 	Email    *string `json:"email"`
 }
 
-type QueryWithStructsResponse struct {
-	User *User `json:"user"`
-}
-
-type User struct {
-	AuthMethods []AuthMethod `json:"authMethods"`
-}
-
 func QueryWithStructs(client *graphql.Client) (*QueryWithStructsResponse, error) {
 	var retval QueryWithStructsResponse
 	err := client.MakeRequest(context.Background(), `

generate/testdata/SimpleInput.graphql.go

@@ -9,10 +9,10 @@ import (
 )
 
 type SimpleInputQueryResponse struct {
-	User *User `json:"user"`
+	User *SimpleInputQueryUser `json:"user"`
 }
 
-type User struct {
+type SimpleInputQueryUser struct {
 	Id string `json:"id"`
 }
 

generate/testdata/SimpleQuery.graphql.go

@@ -9,10 +9,10 @@ import (
 )
 
 type SimpleQueryResponse struct {
-	User *User `json:"user"`
+	User *SimpleQueryUser `json:"user"`
 }
 
-type User struct {
+type SimpleQueryUser struct {
 	Id string `json:"id"`
 }
 

generate/testdata/TypeName.graphql.go

@@ -9,10 +9,10 @@ import (
 )
 
 type TypeNameQueryResponse struct {
-	User *User `json:"user"`
+	User *TypeNameQueryUser `json:"user"`
 }
 
-type User struct {
+type TypeNameQueryUser struct {
 	Typename *string `json:"__typename"`
 	Id       string  `json:"id"`
 }

generate/testdata/UnionNoFragments.graphql.go

@@ -8,18 +8,26 @@ import (
 	"github.com/Khan/genql/graphql"
 )
 
-type Article struct {
+type UnionNoFragmentsQueryRandomLeafArticle struct {
 	Typename *string `json:"__typename"`
 }
 
-func (v Article) implementsGraphQLInterfaceLeafContent() {}
+func (v UnionNoFragmentsQueryRandomLeafArticle) implementsGraphQLInterfaceUnionNoFragmentsQueryRandomLeafLeafContent() {
+}
 
-type LeafContent interface {
-	implementsGraphQLInterfaceLeafContent()
+type UnionNoFragmentsQueryRandomLeafLeafContent interface {
+	implementsGraphQLInterfaceUnionNoFragmentsQueryRandomLeafLeafContent()
+}
+
+type UnionNoFragmentsQueryRandomLeafVideo struct {
+	Typename *string `json:"__typename"`
+}
+
+func (v UnionNoFragmentsQueryRandomLeafVideo) implementsGraphQLInterfaceUnionNoFragmentsQueryRandomLeafLeafContent() {
 }
 
 type UnionNoFragmentsQueryResponse struct {
-	RandomLeaf LeafContent `json:"-"`
+	RandomLeaf UnionNoFragmentsQueryRandomLeafLeafContent `json:"-"`
 }
 
 func (v *UnionNoFragmentsQueryResponse) UnmarshalJSON(b []byte) error {
@@ -29,7 +37,7 @@ func (v *UnionNoFragmentsQueryResponse) UnmarshalJSON(b []byte) error {
 	}
 	firstPass.UnionNoFragmentsQueryResponse = v
 
-	err := json.Unmarshal(b, &typenames)
+	err := json.Unmarshal(b, &firstPass)
 	if err != nil {
 		return err
 	}
@@ -44,12 +52,14 @@ func (v *UnionNoFragmentsQueryResponse) UnmarshalJSON(b []byte) error {
 	switch tn.TypeName {
 
 	case "Article":
-		v.RandomLeaf = Article{}
+
+		v.RandomLeaf = UnionNoFragmentsQueryRandomLeafArticle{}
 		err = json.Unmarshal(
 			firstPass.RandomLeaf, &v.RandomLeaf)
 
 	case "Video":
-		v.RandomLeaf = Video{}
+
+		v.RandomLeaf = UnionNoFragmentsQueryRandomLeafVideo{}
 		err = json.Unmarshal(
 			firstPass.RandomLeaf, &v.RandomLeaf)
 
@@ -58,14 +68,9 @@ func (v *UnionNoFragmentsQueryResponse) UnmarshalJSON(b []byte) error {
 		return err
 	}
 
+	return nil
 }
 
-type Video struct {
-	Typename *string `json:"__typename"`
-}
-
-func (v Video) implementsGraphQLInterfaceLeafContent() {}
-
 func UnionNoFragmentsQuery(client *graphql.Client) (*UnionNoFragmentsQueryResponse, error) {
 	var retval UnionNoFragmentsQueryResponse
 	err := client.MakeRequest(context.Background(), `

generate/testdata/UsesEnumTwice.graphql.go

@@ -8,31 +8,31 @@ import (
 	"github.com/Khan/genql/graphql"
 )
 
-type Role string
-
-const (
-	StudentRole Role = "STUDENT"
-	TeacherRole Role = "TEACHER"
-)
-
-type Role1 string
-
-const (
-	StudentRole1 Role1 = "STUDENT"
-	TeacherRole1 Role1 = "TEACHER"
-)
-
-type User struct {
-	Roles []Role `json:"roles"`
+type UsesEnumTwiceQueryMeUser struct {
+	Roles []UsesEnumTwiceQueryMeUserRolesRole `json:"roles"`
 }
 
-type User1 struct {
-	Roles []Role1 `json:"roles"`
+type UsesEnumTwiceQueryMeUserRolesRole string
+
+const (
+	UsesEnumTwiceQueryMeUserRolesRoleStudent UsesEnumTwiceQueryMeUserRolesRole = "STUDENT"
+	UsesEnumTwiceQueryMeUserRolesRoleTeacher UsesEnumTwiceQueryMeUserRolesRole = "TEACHER"
+)
+
+type UsesEnumTwiceQueryOtherUser struct {
+	Roles []UsesEnumTwiceQueryOtherUserRolesRole `json:"roles"`
 }
 
+type UsesEnumTwiceQueryOtherUserRolesRole string
+
+const (
+	UsesEnumTwiceQueryOtherUserRolesRoleStudent UsesEnumTwiceQueryOtherUserRolesRole = "STUDENT"
+	UsesEnumTwiceQueryOtherUserRolesRoleTeacher UsesEnumTwiceQueryOtherUserRolesRole = "TEACHER"
+)
+
 type UsesEnumTwiceQueryResponse struct {
-	Me        *User
-	OtherUser *User1
+	Me        *UsesEnumTwiceQueryMeUser
+	OtherUser *UsesEnumTwiceQueryOtherUser
 }
 
 func UsesEnumTwiceQuery(client *graphql.Client) (*UsesEnumTwiceQueryResponse, error) {

generate/types.go

@@ -2,14 +2,14 @@ package generate
 
 import (
 	"fmt"
-	"strconv"
 	"strings"
 
 	"github.com/vektah/gqlparser/ast"
 )
 
 type typeBuilder struct {
-	typeName string
+	typeName       string
+	typeNamePrefix string
 	strings.Builder
 	*generator
 }
@@ -29,7 +29,8 @@ func (g *generator) baseTypeForOperation(operation ast.Operation) *ast.Definitio
 
 func (g *generator) getTypeForOperation(operation *ast.OperationDefinition) (name string, err error) {
 	// TODO: configure ResponseName format
-	name = operation.Name + "Response"
+	namePrefix := upperFirst(operation.Name)
+	name = namePrefix + "Response"
 
 	if def, ok := g.typeMap[name]; ok {
 		// TODO: check for and handle conflicts a better way
@@ -42,45 +43,68 @@ func (g *generator) getTypeForOperation(operation *ast.OperationDefinition) (nam
 	}
 
 	return g.addTypeForDefinition(
-		name, g.baseTypeForOperation(operation.Operation), fields)
+		namePrefix, name, g.baseTypeForOperation(operation.Operation), fields)
 }
 
-func (g *generator) addTypeForDefinition(nameOverride string, typ *ast.Definition, fields []field) (name string, err error) {
+var builtinTypes = map[string]string{
+	"Int":     "int", // TODO: technically int32 is always enough, use that?
+	"Float":   "float64",
+	"String":  "string",
+	"Boolean": "bool",
+	"ID":      "string", // TODO: named type for IDs?
+}
+
+func (g *generator) addTypeForDefinition(namePrefix, nameOverride string, typ *ast.Definition, fields []field) (name string, err error) {
+	// If this is a builtin type, just refer to it.
 	goName, ok := builtinTypes[typ.Name]
 	if ok {
 		return goName, nil
 	}
 
 	if nameOverride != "" {
+		// if we have an explicit name, the passed-in prefix is what we
+		// propagate forward
 		name = nameOverride
 	} else {
-		// TODO: casing should be configurable
-		name = upperFirst(typ.Name)
+		typeGoName := upperFirst(typ.Name)
+		if strings.HasSuffix(namePrefix, typeGoName) {
+			// If the field and type names are the same, we can avoid the
+			// duplication.  (We include the field name in case there are
+			// multiple fields with the same type, and the type name because
+			// that's the actual name (the rest are really qualifiers); but if
+			// they are the same then including it once suffices for both
+			// purposes.)
+			name = namePrefix
+		} else {
+			name = namePrefix + typeGoName
+		}
+
+		if typ.Kind != ast.Interface && typ.Kind != ast.Union {
+			// for interface/union types, we do not add the type name to the
+			// name prefix; we want to have QueryFieldType rather than
+			// QueryFieldInterfaceType.  Otherwise, the name will also be the
+			// prefix for the next type.
+			namePrefix = name
+		}
+
 	}
 
-	// TODO: in some cases we can deduplicate, do that
-	// TODO: nicer naming scheme
-	i := 0
-	origName := name
-	for g.typeMap[name] != "" {
-		i++
-		name = origName + strconv.Itoa(i)
-	}
-
-	builder := &typeBuilder{typeName: name, generator: g}
+	// Otherwise, build the type, put that in the type-map, and return its
+	// name.
+	builder := &typeBuilder{typeName: name, typeNamePrefix: namePrefix, generator: g}
 	fmt.Fprintf(builder, "type %s ", name)
 	err = builder.writeTypedef(typ, fields)
 	if err != nil {
 		return "", err
 	}
-
 	g.typeMap[name] = builder.String()
 	return name, nil
 }
 
 func (g *generator) getTypeForInputType(typ *ast.Type) (string, error) {
-	builder := &typeBuilder{typeName: upperFirst(typ.Name()), generator: g}
-	err := builder.writeType(typ, selectionsForType(g, typ))
+	typeName := upperFirst(typ.Name())
+	builder := &typeBuilder{typeName: typeName, typeNamePrefix: typeName, generator: g}
+	err := builder.writeType("", typ, selectionsForType(g, typ))
 	return builder.String(), err
 }
 
@@ -167,7 +191,17 @@ func (builder *typeBuilder) writeField(field field) error {
 		return err
 	}
 
-	err = builder.writeType(typ, fields)
+	err = builder.writeType(
+		// Note we don't deduplicate here -- if our prefix is GetUser and the
+		// field name is User, we do GetUserUser.  This is important because if
+		// you have a field called user on a type called User we need
+		// `query q { user { user { id } } }` to generate two types, QUser and
+		// QUserUser.
+		// Note also this is the alias, not the field-name, because if we have
+		// `query q { a: f { b }, c: f { d } }` we need separate types for a
+		// and c, even though they are the same type in GraphQL, because they
+		// have different fields.
+		builder.typeNamePrefix+upperFirst(field.Alias()), typ, fields)
 	if err != nil {
 		return err
 	}
@@ -182,20 +216,10 @@ func (builder *typeBuilder) writeField(field field) error {
 	return nil
 }
 
-var builtinTypes = map[string]string{
-	"Int":     "int", // TODO: technically int32 is always enough, use that?
-	"Float":   "float64",
-	"String":  "string",
-	"Boolean": "bool",
-	"ID":      "string", // TODO: named type for IDs?
-}
-
-func (builder *typeBuilder) writeType(typ *ast.Type, fields []field) error {
-	// gqlgen does slightly different things here since it defines names for
-	// all the intermediate types, but its implementation may be useful to crib
-	// from:
+func (builder *typeBuilder) writeType(namePrefix string, typ *ast.Type, fields []field) error {
+	// gqlgen does slightly different things here, but its implementation may
+	// be useful to crib from:
 	// https://github.com/99designs/gqlgen/blob/master/plugin/modelgen/models.go#L113
-	// TODO: or maybe we should do that?
 	if typ.Elem != nil {
 		// Type is a list.
 		builder.WriteString("[]")
@@ -207,7 +231,7 @@ func (builder *typeBuilder) writeType(typ *ast.Type, fields []field) error {
 
 	def := builder.schema.Types[typ.Name()]
 	// Writes a typedef elsewhere (if not already defined)
-	name, err := builder.addTypeForDefinition("", def, fields)
+	name, err := builder.addTypeForDefinition(namePrefix, "", def, fields)
 	if err != nil {
 		return err
 	}
@@ -244,7 +268,7 @@ func (builder *typeBuilder) writeTypedef(typedef *ast.Definition, fields []field
 		// Then, write the implementations.
 		// TODO(benkraft): Put a doc-comment somewhere with the list.
 		for _, impldef := range builder.schema.GetPossibleTypes(typedef) {
-			name, err := builder.addTypeForDefinition("", impldef, fields)
+			name, err := builder.addTypeForDefinition(builder.typeNamePrefix, "", impldef, fields)
 			if err != nil {
 				return err
 			}
@@ -263,7 +287,7 @@ func (builder *typeBuilder) writeTypedef(typedef *ast.Definition, fields []field
 		for _, val := range typedef.EnumValues {
 			// TODO: casing should be configurable
 			fmt.Fprintf(builder, "%s %s = \"%s\"\n",
-				goConstName(val.Name+"_"+builder.typeName),
+				builder.typeNamePrefix+goConstName(val.Name),
 				builder.typeName, val.Name)
 		}
 		builder.WriteString(")\n")

generate/unmarshal.go

@@ -33,8 +33,9 @@ func (builder *typeBuilder) maybeWriteUnmarshal(fields []field) error {
 			for _, typedef := range builder.schema.GetPossibleTypes(typedef) {
 				fieldInfo.ConcreteTypes = append(fieldInfo.ConcreteTypes,
 					concreteType{
-						// TODO: lies!  We might have added "1" or something.
-						GoName:      upperFirst(typedef.Name),
+						// TODO: this is quite fragile (and maybe wrong if the
+						// field name + type name are the same)
+						GoName:      builder.typeNamePrefix + fieldInfo.GoName + upperFirst(typedef.Name),
 						GraphQLName: typedef.Name,
 					})
 			}

generate/unmarshal.go.tmpl

@@ -7,7 +7,7 @@ func (v *{{.Type}}) UnmarshalJSON(b []byte) error {
 	}
 	firstPass.{{.Type}} = v
 
-	err := json.Unmarshal(b, &typenames)
+	err := json.Unmarshal(b, &firstPass)
     if err != nil {
         return err
     }
@@ -22,6 +22,7 @@ func (v *{{.Type}}) UnmarshalJSON(b []byte) error {
     {{with $field := .}}
     {{range $field.ConcreteTypes}}
 	case "{{.GraphQLName}}":
+        {{/* TODO: handle repeated fields! */}}
 		v.{{$field.GoName}} = {{.GoName}}{}
 		err = json.Unmarshal(
 			firstPass.{{$field.GoName}}, &v.{{$field.GoName}})
@@ -32,4 +33,5 @@ func (v *{{.Type}}) UnmarshalJSON(b []byte) error {
         return err
     }
     {{end}}
+    return nil
 }

generate/util.go

@@ -25,6 +25,7 @@ func lowerFirst(s string) string {
 }
 
 func upperFirst(s string) string {
+	// TODO: initialisms
 	return changeFirst(strings.TrimLeft(s, "_"), unicode.ToUpper)
 }