From 1f70e53cda5756d546419871e26915e6a6f764b5 Mon Sep 17 00:00:00 2001
From: Eric Stroczynski <ericstroczynski@gmail.com>
Date: Wed, 8 May 2019 10:09:33 -0700
Subject: [PATCH] cmd/operator-sdk/add/api.go: check if go file exists in
 pkg/apis/<group> before scaffolding stub

---
 cmd/operator-sdk/add/api.go   | 37 +++++++++++++++++++++++++++++++++--
 internal/pkg/scaffold/stub.go |  2 ++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/cmd/operator-sdk/add/api.go b/cmd/operator-sdk/add/api.go
index 47f20310f5b..692a9f30072 100644
--- a/cmd/operator-sdk/add/api.go
+++ b/cmd/operator-sdk/add/api.go
@@ -16,11 +16,15 @@ package add
 
 import (
 	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
 
 	"github.com/operator-framework/operator-sdk/cmd/operator-sdk/internal/genutil"
 	"github.com/operator-framework/operator-sdk/internal/pkg/scaffold"
 	"github.com/operator-framework/operator-sdk/internal/pkg/scaffold/input"
 	"github.com/operator-framework/operator-sdk/internal/util/projutil"
+	"github.com/pkg/errors"
 
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
@@ -102,10 +106,16 @@ func apiRun(cmd *cobra.Command, args []string) error {
 		Repo:           projutil.CheckAndGetProjectGoPkg(),
 		AbsProjectPath: absProjectPath,
 	}
-
 	s := &scaffold.Scaffold{}
+
+	// Check if any package files for this API group dir exist, and if not
+	// scaffold a stub.go to prevent erroneous gengo parse errors.
+	stub := &scaffold.Stub{Resource: r}
+	if err := scaffoldIfNoPkgFileExists(s, cfg, stub); err != nil {
+		return errors.Wrap(err, "scaffold stub file")
+	}
+
 	err = s.Execute(cfg,
-		&scaffold.Stub{Resource: r},
 		&scaffold.Types{Resource: r},
 		&scaffold.AddToScheme{Resource: r},
 		&scaffold.Register{Resource: r},
@@ -135,3 +145,26 @@ func apiRun(cmd *cobra.Command, args []string) error {
 	log.Info("API generation complete.")
 	return nil
 }
+
+// scaffoldIfNoPkgFileExists executes f using s and cfg if no go files
+// in f's directory exist.
+func scaffoldIfNoPkgFileExists(s *scaffold.Scaffold, cfg *input.Config, f input.File) error {
+	i, err := f.GetInput()
+	if err != nil {
+		return errors.Wrapf(err, "error getting file %s input", i.Path)
+	}
+	groupDir := filepath.Dir(i.Path)
+	gdInfos, err := ioutil.ReadDir(groupDir)
+	if err != nil && !os.IsNotExist(err) {
+		return errors.Wrapf(err, "error reading dir %s", groupDir)
+	}
+	if err == nil {
+		for _, info := range gdInfos {
+			if !info.IsDir() && filepath.Ext(info.Name()) == ".go" {
+				return nil
+			}
+		}
+	}
+	// err must be a non-existence error or no go files exist, so execute f.
+	return s.Execute(cfg, f)
+}
diff --git a/internal/pkg/scaffold/stub.go b/internal/pkg/scaffold/stub.go
index ee2a7b63d96..5bf47d876ea 100644
--- a/internal/pkg/scaffold/stub.go
+++ b/internal/pkg/scaffold/stub.go
@@ -28,6 +28,8 @@ type Stub struct {
 	Resource *Resource
 }
 
+var _ input.File = &Stub{}
+
 func (s *Stub) GetInput() (input.Input, error) {
 	if s.Path == "" {
 		s.Path = filepath.Join(ApisDir, s.Resource.GoImportGroup, StubFile)