Setup a default boilerplate

staging/src/k8s.io/code-generator/pkg/codegen/helpers/args.go

@@ -18,6 +18,7 @@ package helpers
 
 import (
 	"errors"
+	"k8s.io/code-generator/pkg/current"
 	"os"
 	"path"
 	"path/filepath"
@@ -62,6 +63,13 @@ func (a *Args) Validate() error {
 
 	}
 	a.root = root
+	if len(a.Boilerplate) == 0 {
+		if b, err := defaultBoilerplate(); err != nil {
+			return err
+		} else {
+			a.Boilerplate = b
+		}
+	}
 	if len(a.Boilerplate) > 0 && !isReadable(a.Boilerplate) {
 		return ErrBoilerplateIsntReadable
 	}
@@ -73,6 +81,15 @@ func (a *Args) Validate() error {
 	return nil
 }
 
+func defaultBoilerplate() (string, error) {
+	dir, err := current.Dir()
+	if err != nil {
+		return "", err
+	}
+	codegenRoot := path.Dir(path.Dir(dir))
+	return path.Join(codegenRoot, "examples", "hack", "boilerplate.go.txt"), nil
+}
+
 func isReadable(path string) bool {
 	_, err := os.Stat(path)
 	return err == nil

staging/src/k8s.io/code-generator/pkg/codegen/helpers/deepcopy.go

@@ -73,9 +73,7 @@ func generateDeepCopyHelpers(args *Args, pkgs []string) error {
 	dcargs := []string{
 		"-O", "zz_generated.deepcopy",
 		"--output-base", args.OutputBase,
-	}
-	if args.Boilerplate != "" {
-		dcargs = append(dcargs, "--go-header-file", args.Boilerplate)
+		"--go-header-file", args.Boilerplate,
 	}
 	for _, pkg := range pkgs {
 		dcargs = append(dcargs, "--input-dirs", pkg)

staging/src/k8s.io/code-generator/pkg/current/dir.go

@@ -0,0 +1,28 @@
+/*
+ Copyright 2023 The Kubernetes 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 current
+
+import "path/filepath"
+
+// Dir is the __dirname equivalent.
+func Dir() (string, error) {
+	filename, err := File()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Dir(filename), nil
+}

staging/src/k8s.io/code-generator/pkg/current/file.go

@@ -0,0 +1,33 @@
+/*
+ Copyright 2023 The Kubernetes 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 current
+
+import (
+	"errors"
+	"runtime"
+)
+
+var ErrCantGetCurrentFilename = errors.New("unable to get the current filename")
+
+// File is the __filename equivalent
+func File() (string, error) {
+	_, filename, _, ok := runtime.Caller(1)
+	if !ok {
+		return "", ErrCantGetCurrentFilename
+	}
+	return filename, nil
+}