[BUG] Importing himl adds root logging formatter which affects application logging. #210
Description
Bug Description
A change somewhere between v0.16.0 and v0.18.0 has caused applications that import himl and use a custom log formatter to receive duplicated log messages.
To Reproduce
$ cat himl_logging_bug.py
import argparse
import logging
parser = argparse.ArgumentParser()
parser.add_argument("--himl", action="store_true", help="Import himl")
args = parser.parse_args()
if args.himl:
import himl
logger = logging.getLogger("my_logger")
logger.setLevel(logging.INFO)
formatter = logging.Formatter("%(asctime)s - %(levelname)s - %(name)s - %(message)s")
console_handler = logging.StreamHandler()
console_handler.setFormatter(formatter)
logger.addHandler(console_handler)
logger.info("Test log message")
$ pip install himl==0.16.0 &>/dev/null
$ python himl_logging_bug.py
2025-12-03 12:02:40,599 - INFO - my_logger - Test log message
$ python himl_logging_bug.py --himl
2025-12-03 12:02:43,993 - INFO - my_logger - Test log message
$ pip install himl==0.18.0 &>/dev/null
$ python himl_logging_bug.py
2025-12-03 12:02:54,574 - INFO - my_logger - Test log message
$ python himl_logging_bug.py --himl
2025-12-03 12:02:56,520 - INFO - my_logger - Test log message
INFO:my_logger:Test log message
Expected Behavior
Importing himl does not affect application logging.
Actual Behavior
Importing himl causes duplicated log messages.
Environment
- OS: Fedora 42
- Python version: 3.13.7
- himl version: 0.18.0
- Installation method: pip