feat: Support generic output type

interfaces/generate.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"path"
 	"reflect"
+	"regexp"
 	"strings"
 	"text/template"
 
@@ -87,6 +88,19 @@ func Generate(clients []any, dir string, opts ...Option) error {
 	return nil
 }
 
+func normalizedGenericTypeName(str string) string {
+	// Generic output types have the full import path in the string value, so we need to normalize it
+	pattern := regexp.MustCompile(`\[(.*?)\]`)
+	groups := pattern.FindStringSubmatch((str))
+	if len(groups) < 2 {
+		return str
+	}
+
+	typeName := groups[1]
+	normalizedGenericTypeName := strings.Split(typeName, "/")
+	return pattern.ReplaceAllString(str, "["+normalizedGenericTypeName[len(normalizedGenericTypeName)-1]+"]")
+}
+
 // Adapted from https://stackoverflow.com/a/54129236
 func signature(name string, f any) string {
 	t := reflect.TypeOf(f)
@@ -117,7 +131,7 @@ func signature(name string, f any) string {
 			if i > 0 {
 				buf.WriteString(", ")
 			}
-			buf.WriteString(t.Out(i).String())
+			buf.WriteString(normalizedGenericTypeName(t.Out(i).String()))
 		}
 		if numOut > 1 {
 			buf.WriteString(")")

interfaces/generate_test.go

@@ -11,6 +11,11 @@ import (
 	"github.com/google/go-cmp/cmp"
 )
 
+type Response struct {
+}
+type Pager[T any] struct {
+}
+
 type Client struct{}
 
 func (*Client) ListThings() error {
@@ -25,6 +30,10 @@ func (*Client) CreateTables(_ context.Context, _ []string) error {
 	return nil
 }
 
+func (*Client) NewPager(_ context.Context) *Pager[Response] {
+	return nil
+}
+
 var wantOutput = `// Code generated by codegen; DO NOT EDIT.
 package services
 
@@ -36,17 +45,17 @@ import (
 //go:generate mockgen -package=mocks -destination=../mocks/interfaces.go -source=interfaces.go InterfacesClient
 type InterfacesClient interface {
 	ListTables(context.Context) error
+	NewPager(context.Context) *interfaces.Pager[interfaces.Response]
 }
 `
 
 func TestGenerate(t *testing.T) {
 	dir := t.TempDir()
 	err := Generate([]any{&Client{}}, dir,
 		WithIncludeFunc(func(m reflect.Method) bool {
-			return MethodHasAnyPrefix(m, []string{"List"}) && MethodHasAnySuffix(m, []string{"Tables"})
+			return MethodHasAnyPrefix(m, []string{"List"}) && MethodHasAnySuffix(m, []string{"Tables"}) || MethodHasAnyPrefix(m, []string{"NewPager"})
 		}),
-		WithExtraImports(func(m reflect.Method) []string { return []string{"net/http"} },
-		))
+		WithExtraImports(func(m reflect.Method) []string { return []string{"net/http"} }))
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}