🐛 (go/v4): Simplify init directory validation to only block PROJECT file

pkg/plugins/golang/v4/init.go

@@ -22,7 +22,6 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"unicode"
 
 	"github.com/spf13/pflag"
 
@@ -159,53 +158,24 @@ func (p *initSubcommand) PostScaffold() error {
 }
 
 // checkDir will return error if the current directory has files which are not allowed.
-// Note that, it is expected that the directory to scaffold the project is cleaned.
-// Otherwise, it might face issues to do the scaffold.
+// Only the PROJECT file is disallowed as it will be generated by the scaffolding tool.
 func checkDir() error {
 	err := filepath.Walk(".",
 		func(path string, info os.FileInfo, err error) error {
 			if err != nil {
 				return fmt.Errorf("error walking path %q: %w", path, err)
 			}
-			// Allow directory trees starting with '.'
+			// Skip dot directories
 			if info.IsDir() && strings.HasPrefix(info.Name(), ".") && info.Name() != "." {
 				return filepath.SkipDir
 			}
-			// Allow files starting with '.'
-			if strings.HasPrefix(info.Name(), ".") {
-				return nil
+			// Only block PROJECT file (reserved for scaffolding)
+			if !info.IsDir() && info.Name() == "PROJECT" {
+				return fmt.Errorf("PROJECT file found in target directory. " +
+					"This file is reserved and will be generated by kubebuilder")
 			}
-			// Allow files ending with '.md' extension
-			if strings.HasSuffix(info.Name(), ".md") && !info.IsDir() {
-				return nil
-			}
-			// Allow capitalized files except PROJECT
-			isCapitalized := true
-			for _, l := range info.Name() {
-				if !unicode.IsUpper(l) {
-					isCapitalized = false
-					break
-				}
-			}
-			if isCapitalized && info.Name() != "PROJECT" {
-				return nil
-			}
-			disallowedExtensions := []string{
-				".go",
-				".yaml",
-				".mod",
-				".sum",
-			}
-			// Deny files with .go or .yaml or .mod or .sum extensions
-			for _, ext := range disallowedExtensions {
-				if strings.HasSuffix(info.Name(), ext) {
-					return nil
-				}
-			}
-			// Do not allow any other file
-			return fmt.Errorf("target directory is not empty and contains a disallowed file %q. "+
-				"files with the following extensions [%s] are not allowed to avoid conflicts with the tooling",
-				path, strings.Join(disallowedExtensions, ", "))
+			// Allow everything else
+			return nil
 		})
 	if err != nil {
 		return fmt.Errorf("error walking directory: %w", err)