Deprecate old backward compatible shims in configure_formatter()/handler().

[felixxm]

Feature or enhancement

Proposal:

DictConfigurator.configure_formatter() and configure_handler() contain workarounds for old configurations

cpython/Lib/logging/config.py

Lines 670 to 676 in bcccf1f

	#Name of parameter changed from fmt to format.
	#Retry with old name.
	#This is so that code can be used with older Python versions
	#(e.g. by Django)
	config['fmt'] = config.pop('format')
	config['()'] = factory
	result = self.configure_custom(config)

cpython/Lib/logging/config.py

Lines 844 to 851 in bcccf1f

	if "'stream'" not in str(te):
	raise
	#The argument name changed from strm to stream
	#Retry with old name.
	#This is so that code can be used with older Python versions
	#(e.g. by Django)
	kwargs['strm'] = kwargs.pop('stream')
	result = factory(**kwargs)

Django doesn't use fmt and strm for many years. I think both can be deprecated and removed.

I'd like to prepare a patch, if accepted.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-115032: Update DictConfigurator.configure_formatter() comment about fmt retry. #115303
• gh-115032: Deprecate support for custom logging handlers with 'strm' argument. #115314

[sobolevn]

cc @vsajip

[vsajip]

I realise Django doesn't use them any more, but what about other code / users? I wouldn't strongly object to removing them, but there's a chance that any such change might need to be reverted if there are complaints that it breaks existing code somewhere. And, of course, no backporting of any such change. Perhaps deprecate, but not remove immediately - rather, in line with the usual deprecation cycle. It's just a little wart in the current code, after all.

[felixxm]

Perhaps deprecate, but not remove immediately - rather, in line with the usual deprecation cycle.

Yes that's what I was trying to propose. We have an existing and straightforward upgrade path i.e. use format instead of fmt and use stream instead of strm, so it seems fine to deprecate the current workarounds and remove them in 3.15 (I guess 🤔).

It's just a little wart in the current code, after all.

True, but they become an issue when there are dozens of such workarounds ("death by a thousand cuts").

[vsajip]

become an issue when there are dozens of such workarounds

Well, it's not that bad IMO, but I'll look at a PR that does deprecation.

[felixxm]

While preparing a patch, I noticed that we can deprecate strm, however, fmt is still needed because config is passed directly to the custom formatters and Formatter except fmt instead of format.