Loguru infinite recursion traceback loop

[mpenning]

• ciscoconfparse2 uses loguru in a pretty simple manner, decorating methods with @logger.catch(reraise=True)

My problem is if I hit a bug in certain methods, I get an infinite traceback from loguru. I love loguru when it works, but digging into the infinite recursion is a serious drag on my development because even with a multi-thousand-line scrollback buffer, I still can't hit control-c fast enough to interrupt the infinite loop of loguru messages and find the real cause of the problem (i.e. I have two problems, loguru inifinte recursion and the ciscoconfparse2 bug that caused it).

Is there a way to get loguru to stop printing tracebacks in an infinite loop?

You can reproduce the infinite recursion loop as follows:

• Install loguru==0.7.2
• git clone ciscoconfparse2 to my local system
• cd ciscoconfparse2
• checkout hash 1a7b88d72c5a86a673ba8d4ed18316036c65fded
• run this script (python versions don't seem to matter... I have seen this problem over and over for months with a variety of python versions):

from loguru import logger

from ciscoconfparse2 import CiscoConParse

parse = CiscoConfParse("tests/fixtures/configs/sample_01.junos", syntax="junos", factory=False)
print(parse)
for obj in parse.objs:
    print(obj)

[Delgan]

Hi @mpenning.

Sorry you're experiencing difficulties with Loguru, and thanks for the reproducible example. It boils down to the following:

from loguru import logger


class Foo:
    @logger.catch(reraise=True)
    def __repr__(self):
        raise ValueError("Something went wrong")


if __name__ == "__main__":
    foo = Foo()
    print(foo)

It's definitely a problem with diagnose=True which causes infinite recursion if the exception is raised in __repr__, since v can't be printed:

loguru/loguru/_better_exceptions.py

Lines 331 to 335 in dcf42d9

	def _format_value(self, v):
	try:
	v = repr(v)
	except Exception:
	v = "<unprintable %s object>" % type(v).__name__

I'll try to implement a fix. In the meantime, I advise to use diagnose=False or remove @logger.catch() decorator from __repr__() methods.