Add !ignore_autogenerated build tag (#330)

This appears to be officially supported by `gopls` and is also generated into the deepcopy files that `controller-gen` builds. Let’s use it as well.

hack/generator/pkg/astmodel/file_definition.go

@@ -226,10 +226,13 @@ func (file *FileDefinition) AsAst() ast.Node {
 			})
 	}
 
-	header, headerLen := createComments(
+	var comments []string
+	comments = append(comments, CodeGenerationComments...)
+	comments = append(comments,
 		"Copyright (c) Microsoft Corporation.",
-		"Licensed under the MIT license.",
-		CodeGenerationComment)
+		"Licensed under the MIT license.")
+
+	header, headerLen := createComments(comments...)
 
 	packageName := file.packageReference.PackageName()
 

hack/generator/pkg/astmodel/generation_consts.go

@@ -5,8 +5,16 @@
 
 package astmodel
 
+var (
+	CodeGenerationComments []string = []string{
+		// Compiler-readable comment, must be first in file:
+		"+build !ignore_autogenerated",
+
+		// Note that this format is actually an official specification in go:  https://github.com/golang/go/issues/13560
+		"Code generated by k8s-infra. DO NOT EDIT.", // TODO: Update this when the generated is moved/renamed
+	}
+)
+
 const (
-	// Note that this format is actually an official specification in go:  https://github.com/golang/go/issues/13560
-	CodeGenerationComment   = "Code generated by k8s-infra-gen. DO NOT EDIT." // TODO: Update this when the generated is moved/renamed
 	CodeGeneratedFileSuffix = "_gen.go"
 )

hack/generator/pkg/codegen/pipeline_delete_generated_code.go

@@ -98,8 +98,10 @@ func isFileGenerated(filename string) (bool, error) {
 			return false, err
 		}
 
-		if strings.Contains(line, astmodel.CodeGenerationComment) {
-			return true, nil
+		for _, codeGenComment := range astmodel.CodeGenerationComments {
+			if strings.Contains(line, codeGenComment) {
+				return true, nil
+			}
 		}
 	}
 

hack/generator/pkg/codegen/testdata/EmbeddedTypes/Embedded_type_simple_resource.golden

@@ -1,6 +1,7 @@
+// +build !ignore_autogenerated
+// Code generated by k8s-infra. DO NOT EDIT.
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
-// Code generated by k8s-infra-gen. DO NOT EDIT.
 package v20200101
 
 import (