Merge pull request #995 from isztldav/fix/handle-empty-csv-files

Fix EmptyDataError when reading empty CSV files

Author: benoit-cty

codecarbon/output_methods/file.py

@@ -88,6 +88,11 @@ def out(self, total: EmissionsData, _):
 
         """
         file_exists: bool = os.path.isfile(self.save_file_path)
+        if file_exists and os.path.getsize(self.save_file_path) == 0:
+            logger.warning(
+                f"File {self.save_file_path} exists but is empty. Treating as new file."
+            )
+            file_exists = False
         if file_exists and not self.has_valid_headers(total):
             logger.warning("The CSV format has changed, backing up old emission file.")
             backup(self.save_file_path)

tests/output_methods/test_file.py

@@ -173,6 +173,30 @@ def test_file_output_out_update_file_exists_one_matchingrows(self):
     #     file_output = FileOutput("test.csv", self.temp_dir, on_csv_write="append")
     #     file_output.out(self.emissions_data, None)
 
+    def test_file_output_out_append_empty_file_exists(self):
+        file_output = FileOutput("test.csv", self.temp_dir, on_csv_write="append")
+        # Create an empty file
+        with open(file_output.save_file_path, "w") as _:
+            pass
+
+        # This should not raise an error
+        file_output.out(self.emissions_data, None)
+
+        df = pd.read_csv(os.path.join(self.temp_dir, "test.csv"))
+        self.assertEqual(len(df), 1)
+
+    def test_file_output_out_update_empty_file_exists(self):
+        file_output = FileOutput("test.csv", self.temp_dir, on_csv_write="update")
+        # Create an empty file
+        with open(file_output.save_file_path, "w") as _:
+            pass
+
+        # This should not raise an error
+        file_output.out(self.emissions_data, None)
+
+        df = pd.read_csv(os.path.join(self.temp_dir, "test.csv"))
+        self.assertEqual(len(df), 1)
+
     def test_file_output_task_out(self):
         task_emissions_data = [
             TaskEmissionsData(