Replace os.Rename with copy and delete

main.go

@@ -172,7 +172,7 @@ func moveBuildArtifacts(outDirectory, romDirectory string) bool {
 		}
 		newROMs = true
 		log.Printf("new build found - moving file %s", v.Name())
-		err := os.Rename(fmt.Sprintf("%s/%s", outDirectory, v.Name()), fmt.Sprintf("%s/%s", romDirectory, v.Name()))
+		err := moveBuildFile(fmt.Sprintf("%s/%s", outDirectory, v.Name()), fmt.Sprintf("%s/%s", romDirectory, v.Name()))
 		if err != nil {
 			log.Printf("failed to move file '%s' from out to rom directory: %v", v.Name(), err)
 			continue
@@ -222,3 +222,39 @@ func hashFile(filename string) (string, error) {
 
 	return fmt.Sprintf("%x", h.Sum(nil)), nil
 }
+
+// A custom "move file" function because in docker container the mounted folders are different overlay filesystems
+// Instead of os.Rename, we must copy and delete
+func moveBuildFile(src, dst string) error {
+	sourceFileStat, err := os.Stat(src)
+	if err != nil {
+		return err
+	}
+
+	if !sourceFileStat.Mode().IsRegular() {
+		return fmt.Errorf("%s is not a regular file", src)
+	}
+
+	source, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer source.Close()
+
+	destination, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer destination.Close()
+	_, err = io.Copy(destination, source)
+	if err != nil {
+		return fmt.Errorf("failed to copy file: %v", err)
+	}
+
+	err = os.Remove(src)
+	if err != nil {
+		return fmt.Errorf("failed to delete source file after copy: %v", err)
+	}
+
+	return nil
+}