Logs are getting auto deleted after the date is changed.

Bug report

Bug description:

I have written a code that would rotate logs on midnight maintaing backup of 1 day. But the next day, the previous logs are getting deleted.

For example :
While I am checking logs on 14th Feb, I noticed that all the logs generated on 13th Feb, got deleted from instancelogs.log.2025-02-13. The first log generated on 14th Feb is getting stored in instancelogs.log.2025-02-13 file instead of instancelogs.log file , the remaining logs for 14th Feb are correctly stored in instancelogs.log file.

Please look into the issue as we are losing all the logs for 13th of Feb.

I am using below code to handle logs:

import logging
from logging.handlers import TimedRotatingFileHandler


#logger instances for PPT creator
LOG_FILE_PATH = "../STORE_LOGS/instancelogs.log"

instance_logger = logging.getLogger('instance_logger')

instance_logger_file_handler = None


instance_logger_file_handler = TimedRotatingFileHandler(LOG_FILE_PATH, when='midnight', interval=1, backupCount=1)
instance_logger_file_formatter = logging.Formatter(
    fmt="[%(asctime)s] - [%(levelname)s]  - [%(filename)s] - [%(funcName)s] - %(message)s",
    datefmt="%d-%m-%y %H:%M:%S")
instance_logger_file_handler.setFormatter(instance_logger_file_formatter)

instance_logger.setLevel(logging.DEBUG)
instance_logger.addHandler(instance_logger_file_handler)

CPython versions tested on:

3.9

Operating systems tested on:

Linux

Python logging.handlers.TimedRotatingFileHandler の実装とその rollover 動作から始め、提供されている午前0時の設定を再現ケースとして使用します。午前0時以降の最初のレコードがローテーション後のファイル名にどのように割り当てられるか、また backupCount=1 がどのようにファイルを削除するかを確認します。前日のログがそのまま保持され、新しい日のレコードがアクティブなログファイルに書き込まれ、このケースに対する回帰テストのカバレッジがあることを完了条件とします。