caplog.set_level/caplog.at_level bounded by log_level config?

[Kemp-J]

I see there are a number of issues on the tracker around this, both open and closed, with some closed ones implying this behaviour should no longer be occurring. I'd like to get some clarity on the current status of things and any expected changes coming up.

I am currently using pytest 9.0.2.

Currently if, for example, log_level in the ini file is set to INFO and a test calls caplog.set_level(logging.DEBUG) (or uses the equivalent at_level context manager), this does not log any messages at the DEBUG level during the test. The global INFO setting still applies.

When I went looking for answers on this I found #7133, which looked like this exact problem and seemed to have already been solved in pull request #7340. Unless I'm missing something, I still have the same issue though. I see there are other open issues such as #7162 which seem to be talking about the same/a similar thing, but as I dig around and find more of them they get a bit further into the pytest internals than I'm familiar with as a user rather than a developer of the package.

Is what I'm seeing expected behaviour, or did the bug from 6 years ago rear its head again at some point?

[gistrec]

From the docs and the older issues, I would not treat this as expected behavior for the basic case.

As I understand it:

• caplog.set_level() doesn't override log_level #7133 was the original bug: log_level = INFO prevented caplog.set_level(logging.DEBUG) from capturing DEBUG records
• Allow tests to override "global" log_level (rebased) #7340 fixed that by making caplog.set_level() adjust both the logger level and the capture handler level
• caplog fixture should not be affected by global log level #7162 is a separate design discussion about whether caplog should ignore the global log_level by default. That may still affect future behavior, but it does not change the current expectation for explicit caplog.set_level()

So this should work:

import logging

def test_debug_logging(caplog):
    caplog.set_level(logging.DEBUG)

    logging.debug("debug message")

    assert "debug message" in caplog.text

If this minimal example fails on pytest 9.0.2 with log_level = INFO, I would consider that a regression/bug rather than intended behavior

If the minimal example works but your real project does not, I would check two common logging gotchas

First, make sure the root logger handlers are not being replaced during the test or app initialization. The caplog fixture captures logs by adding a handler to the root logger. If code calls logging.config.dictConfig, fileConfig, or otherwise replaces root handlers, the caplog handler can be removed, and then no caplog.set_level() call will help because the capture handler is gone

Second, check whether your application logger has propagate = False or its own explicit level/handlers. In that case records may never reach the root logger where caplog is attached. Then target the actual logger:

import logging

logger = logging.getLogger("myapp")

def test_debug_logging(caplog):
    caplog.set_level(logging.DEBUG, logger="myapp")

    logger.debug("debug message")

    assert "debug message" in caplog.text

So the short answer is: the basic behavior you describe should not be expected after #7340. If a minimal root-logger repro fails, it is likely a regression. If only your project fails, I would first look for logging reconfiguration or non-propagating named loggers