internal/pkg/scaffold: add group.go scaffold to prevent deepcopy parse errors

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Enables controller-runtime metrics in Helm operator projects. ([#1482](https://github.com/operator-framework/operator-sdk/pull/1482))
 - New flags `--vendor` and `--skip-validation` for [`operator-sdk new`](https://github.com/operator-framework/operator-sdk/blob/master/doc/sdk-cli-reference.md#new) that direct the SDK to initialize a new project with a `vendor/` directory, and without validating project dependencies. `vendor/` is not written by default. ([#1519](https://github.com/operator-framework/operator-sdk/pull/1519))
 - Generating and serving info metrics about each custom resource. By default these metrics are exposed on port 8686. ([#1277](https://github.com/operator-framework/operator-sdk/pull/1277))
+- Scaffold a `pkg/apis/<group>/group.go` package file to avoid `go/build` errors when running Kubernetes code generators. ([#1401](https://github.com/operator-framework/operator-sdk/pull/1401))
 
 ### Changed
 

cmd/operator-sdk/add/api.go

@@ -16,12 +16,16 @@ 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"
 )
@@ -102,8 +106,15 @@ 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 group.go to prevent erroneous gengo parse errors.
+	group := &scaffold.Group{Resource: r}
+	if err := scaffoldIfNoPkgFileExists(s, cfg, group); err != nil {
+		return errors.Wrap(err, "scaffold group file")
+	}
+
 	err = s.Execute(cfg,
 		&scaffold.Types{Resource: r},
 		&scaffold.AddToScheme{Resource: r},
@@ -134,3 +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)
+}

internal/pkg/scaffold/group.go

@@ -0,0 +1,47 @@
+// Copyright 2019 The Operator-SDK Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package scaffold
+
+import (
+	"path/filepath"
+
+	"github.com/operator-framework/operator-sdk/internal/pkg/scaffold/input"
+)
+
+const GroupFile = "group.go"
+
+type Group struct {
+	input.Input
+
+	Resource *Resource
+}
+
+var _ input.File = &Group{}
+
+func (s *Group) GetInput() (input.Input, error) {
+	if s.Path == "" {
+		s.Path = filepath.Join(ApisDir, s.Resource.GoImportGroup, GroupFile)
+	}
+	s.TemplateBody = groupTmpl
+	return s.Input, nil
+}
+
+const groupTmpl = `// Package {{.Resource.GoImportGroup}} contains {{.Resource.GoImportGroup}} API versions.
+//
+// This file ensures Go source parsers acknowledge the {{.Resource.GoImportGroup}} package
+// and any child packages. It can be removed if any other Go source files are
+// added to this package.
+package {{.Resource.GoImportGroup}}
+`