unions are easy too, sorta

README.md

@@ -60,7 +60,6 @@ TODO(benkraft): Figure out how to get GitHub Actions to run the example -- it ne
 ## Major TODOs
 
 Query structures to support:
-- unions
 - fragments
 
 Config options:

generate/testdata/InterfaceNoFragments.graphql.go

@@ -1,12 +1,10 @@
 type Response struct {
 	Root struct {
-		Id       string    `json:"id"`
-		Name     string    `json:"name"`
-		Children []content `json:"children"`
+		Id       string `json:"id"`
+		Name     string `json:"name"`
+		Children []struct {
+			Id   string `json:"id"`
+			Name string `json:"name"`
+		} `json:"children"`
 	} `json:"root"`
-}
-
-type content struct {
-	Id   string `json:"id"`
-	Name string `json:"name"`
 }

generate/testdata/UnionNoFragments.graphql

@@ -0,0 +1,5 @@
+{
+  randomLeaf {
+    __typename
+  }
+}

generate/testdata/UnionNoFragments.graphql.go

@@ -0,0 +1,5 @@
+type Response struct {
+	RandomLeaf struct {
+		Typename *string `json:"__typename"`
+	} `json:"randomLeaf"`
+}

generate/testdata/schema.graphql

@@ -32,6 +32,8 @@ interface Content {
   parent: Topic
 }
 
+union LeafContent = Article | Video
+
 type Article implements Content {
   id: ID!
   name: String!
@@ -56,4 +58,5 @@ type Topic implements Content {
 type Query {
   user(query: UserQueryInput): User
   root: Topic!
+  randomLeaf: LeafContent!
 }

generate/types.go

@@ -200,9 +200,8 @@ func (builder *typeBuilder) writeType(typ *ast.Type, selectionSet []selection, i
 	}
 
 	def := builder.schema.Types[typ.Name()]
-	// TODO: set inline = false for nested types
 	switch def.Kind {
-	case ast.Scalar, ast.Enum, ast.Union, ast.Interface:
+	case ast.Scalar, ast.Enum:
 		inline = false
 	}
 
@@ -222,7 +221,7 @@ func (builder *typeBuilder) writeType(typ *ast.Type, selectionSet []selection, i
 
 func (builder *typeBuilder) writeTypedef(typedef *ast.Definition, selectionSet []selection) error {
 	switch typedef.Kind {
-	case ast.Object, ast.InputObject, ast.Interface:
+	case ast.Object, ast.InputObject, ast.Interface, ast.Union:
 		builder.WriteString("struct {\n")
 		for _, field := range selectionSet {
 			err := builder.writeField(field)
@@ -244,7 +243,7 @@ func (builder *typeBuilder) writeTypedef(typedef *ast.Definition, selectionSet [
 		}
 		builder.WriteString(")\n")
 		return nil
-	case ast.Scalar, ast.Union:
+	case ast.Scalar:
 		// TODO(benkraft): Handle custom scalars, unions, and interfaces.
 		return fmt.Errorf("not implemented: %v", typedef.Kind)
 	default: