Logging docs don't address the creation of multiple loggers when a hierarchy is provided

[flipdazed]

BPO	39540
Nosy	@vsajip, @flipdazed

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2020-02-19.19:56:30.420>
created_at = <Date 2020-02-03.12:29:54.046>
labels = ['3.7', '3.8', '3.9', 'type-feature', 'invalid', 'docs']
title = "Logging docs don't address the creation of multiple loggers when a hierarchy is provided"
updated_at = <Date 2020-02-19.19:56:30.420>
user = 'https://github.com/flipdazed'

bugs.python.org fields:

activity = <Date 2020-02-19.19:56:30.420>
actor = 'vinay.sajip'
assignee = 'docs@python'
closed = True
closed_date = <Date 2020-02-19.19:56:30.420>
closer = 'vinay.sajip'
components = ['Documentation']
creation = <Date 2020-02-03.12:29:54.046>
creator = 'flipdazed'
dependencies = []
files = []
hgrepos = []
issue_num = 39540
keywords = []
message_count = 2.0
messages = ['361287', '361337']
nosy_count = 3.0
nosy_names = ['vinay.sajip', 'docs@python', 'flipdazed']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue39540'
versions = ['Python 3.6', 'Python 3.7', 'Python 3.8', 'Python 3.9']

[flipdazed]

If logger_name is a hierarchy format (e.g. logger_name = 'parent.child') and the logger name 'parent' has not been created, the function call logging.getLogger(logger_name) will create all loggers in the hierarchy (in this instance two loggers, 'parent' and 'parent.child' will be created)

This is not documented anywhere in the logging documentation. Suggest that this is detailed under logging.getLogger

More info...
https://stackoverflow.com/q/59990300/4013571

[vsajip]

That's an internal detail. In fact loggers aren't created for all loggers in the hierarchy - PlaceHolder objects are created internally for hierarchy ancestors, and converted to loggers if needed. The printout from your linked Stack Overflow question shows this.

This is not documented because it's internal implementation detail. How the dotted-name hierarchy works is documented.