shutdown function of logging module does not empty _loggers

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
45/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Stale
Tech stack
python
Domain
tooling

Research direction

Start in logging.py around line 213 and reproduce the failure with the code in the issue. Check how logging.shutdown() handles _loggers and closed handlers, then verify that reusing the logger after shutdown can add a new FileHandler and emit a message without ValueError.

Written by the indexing model from the issue text.

Description

if I want to reuse logger after call shutdown(), I can recreate log_a , add file_handler , but it will failure on log.xxx

Traceback (most recent call last):
...
  File "logging.py", line 141, in info
  File "logging.py", line 135, in log
  File "logging.py", line 71, in emit
ValueError:

the root cause is, after execute logging.shutdown() , all logger remain in _loggers variables, so all handlers remain in logger.handlers, but the old file_handlers was closed, so emit method failure.

we can run follow code to verify it.

import logging
log_a = logging.getLogger('a')
log_a.setLevel(logging.DEBUG)

file_handler = logging.FileHandler('log.txt')
file_handler.setLevel(logging.DEBUG)

formatter = logging.Formatter("%(name)s - %(levelname)s - %(message)s")
file_handler.setFormatter(formatter)
log_a.addHandler(file_handler)

log_a.debug('write to file')

print(logging._loggers)
print(log_a.handlers)
logging.shutdown()

log_a = logging.getLogger('a')
log_a.setLevel(logging.DEBUG)

file_handler = logging.FileHandler('log.txt')
file_handler.setLevel(logging.DEBUG)

formatter = logging.Formatter("%(name)s - %(levelname)s - %(message)s")
file_handler.setFormatter(formatter)
log_a.addHandler(file_handler)

log_a.debug('write to file')

print(logging._loggers)
print(log_a.handlers)

to fixed it, pass name to pop method in line 213

logging._loggers.pop(logger.name, None)

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