logging.config.FileConfig has a kwarg 'disable_existing_loggers' that defaults to False, but when true will allow you to load a config and not disable all other existing loggers.

logging.config.listen uses FileConfig, but has no option to provide this keyword to it, which is a problem when a logger hierarchy is build using logger.getLogger(__name__) (which is recommended in the documentation).

Proposal: Add kwarg 'disable_existing_loggers' to logging.config.listen which is passed to fileConfig.

Used proposed method to solve this bug and implemented the extra kwarg disable_existing_loggers to the listen() parameters.

I think this is just a documentation issue. You can send a dictionary suitable for dictConfig() as JSON over the listen() socket. This is supported by 2.7 and 3.2+ - the documentation doesn't mention this, though.

That's not really what this is about. This is about setting up the listener so that by default that setting is used.

In logging/config.py:

```python
def listen(port=DEFAULT_LOGGING_CONFIG_PORT, verify=None):
...
                            try:
                                fileConfig(file)
                            except Exception:
                                traceback.print_exc()
...

def fileConfig(fname, defaults=None, disable_existing_loggers=True):
...
```

> That's not really what this is about.

As I see it, it's about the ability to configure disabling of existing loggers on reconfiguration via the listener. While it can't be done using fileConfig(), it *can* be done using dictConfig().

New changeset 65a1abf4b432 by Vinay Sajip in branch '3.5':
Closed #26533: expanded on behaviour of logging.config.listen().
https://hg.python.org/cpython/rev/65a1abf4b432

New changeset abd744bf62fb by Vinay Sajip in branch 'default':
Closed #26533: Merged update from 3.5.
https://hg.python.org/cpython/rev/abd744bf62fb