Python 3.8 changes the findCaller method signature which breaks STDLibLogObserver

[twisted-trac]

	@jeremycline reported
Trac ID	trac#9668
Type	defect
Created	2019-07-01 17:02:08Z

Python 3.8 adds a new keyword argument, stacklevel, to its findCaller function in commit dde9fdbe4539 ("bpo-33165: Added stacklevel parameter to logging APIs. (GH-7424)"). As Twisted is replacing this method with its own method, logging with STDLibLogObserver fails in Python 3.8.

This issue was discovered during Fedora's mass rebuild[0] with the Python 3.8 beta when a crochet test started failing[1].

Pull request: #1161

[0] https://bugzilla.redhat.com/show_bug.cgi?id=1724145

[1] https://github.com/itamarst/crochet/blob/8b4178efcaff6d63562c4520cfb128bb9681f9b0/crochet/tests/test_setup.py#L349

Searchable metadata

trac-id__9668 9668
type__defect defect
reporter__jeremycline jeremycline
priority__normal normal
milestone__Python_3_8_Support Python 3.8 Support
branch__ 
branch_author__ 
status__closed closed
resolution__fixed fixed
component__logger logger
keywords__None None
time__1562000528551443 1562000528551443
changetime__1563637975291902 1563637975291902
version__None None
owner__hawkowl hawkowl

[twisted-trac]

	@hawkowl set owner to @hawkowl

This does as it says on the tin on my Python 3.8.0b2.

[twisted-trac]

	Jeremy Cline set status to closed

In changeset c0ce0d7

#!CommitTicketReference repository="" revision="c0ce0d77be9152a8a3645c5bddb6e2f9cc56d98f"
Merge jeremycline:9668-jeremycline-stdlog-findCaller-38-compat: Add the stackLevel kwarg to STDLibLogObserver._findCaller

Author: jeremycline
Reviewer: hawkowl
Fixes: ticket:9668

Python 3.8 adds a new keyword argument, stacklevel, to its findCaller
function in commit dde9fdbe4539 ("bpo-33165: Added stacklevel parameter
to logging APIs. (GH-7424)"). As Twisted is replacing this method with
its own method, logging with STDLibLogObserver fails in Python 3.8. This
patch adds the argument, but does not use it as there is already a
stackDepth instance variable and the stackInfo on the method is also
ignored.

This patch fixes the logger tests that currently fail in Python 3.8.

Signed-off-by: Jeremy Cline <jcline@...>

[twisted-trac]

	@hawkowl commented

Thanks Jeremy!