[BACKEND] Do not write download archive file if no files changed

src/ytdl_sub/cli/main.py

@@ -112,6 +112,9 @@ def main():
         )
 
     for subscription, transaction_log in transaction_logs:
+        if transaction_log.is_empty:
+            logger.info("No files changed for %s", subscription.name)
+        else:
             logger.info(
                 "Downloads for %s:\n%s\n",
                 subscription.name,

src/ytdl_sub/utils/file_handler.py

@@ -93,6 +93,15 @@ class FileHandlerTransactionLog:
         self.files_created: Dict[str, FileMetadata] = {}
         self.files_removed: Set[str] = set()
 
+    @property
+    def is_empty(self) -> bool:
+        """
+        Returns
+        -------
+        True if no transaction logs are recorded. False otherwise
+        """
+        return len(self.files_created) == 0 and len(self.files_removed) == 0
+
     def log_created_file(
         self, file_name: str, file_metadata: Optional[FileMetadata] = None
     ) -> "FileHandlerTransactionLog":

src/ytdl_sub/ytdl_additions/enhanced_download_archive.py

@@ -537,12 +537,13 @@ class EnhancedDownloadArchive:
 
     def save_download_mappings(self) -> "EnhancedDownloadArchive":
         """
-        Saves the updated download mappings to the output directory
+        Saves the updated download mappings to the output directory if any files were changed.
 
         Returns
         -------
         self
         """
+        if not self.get_file_handler_transaction_log().is_empty:
             self._download_mapping.to_file(output_json_file=self._mapping_working_file_path)
             self.save_file_to_output_directory(file_name=self._mapping_file_name)
         return self