This rule raises an issue when logging.error() is used within an exception handler (except block) to log exception information.

Why is this an issue?

When handling exceptions in Python, it’s important to capture not just the error message, but also the full traceback. The traceback shows the sequence of function calls that led to the exception, which is essential for understanding what went wrong and where.

The logging module provides two methods that might seem similar:

• logging.error(): Logs an error message at the ERROR level
• logging.exception(): Logs an error message at the ERROR level AND automatically includes the full exception traceback

When you’re inside an exception handler (except block), you’re dealing with an exception that just occurred. In this context, logging.exception() is the appropriate choice because:

• It automatically captures the traceback without requiring exc_info=True
• It clearly signals to other developers that you’re logging an exception
• It is the purpose-built method for logging exceptions and is the established Python idiom for this use case

Using logging.error() in an exception handler means you’re either:

• Missing the traceback entirely (if you don’t pass exc_info=True), making debugging much harder
• Writing more verbose code (if you do pass exc_info=True) when a simpler, more idiomatic option exists

The logging.exception() method is specifically designed for this use case and is the established Python idiom for logging exceptions.

How to fix it

Replace logging.error() with logging.exception() when logging within an exception handler. If you were using exc_info=True, you can remove it since logging.exception() includes traceback information by default.

Code examples

Noncompliant code example

import logging

try:
    raise ValueError("Invalid value")
except ValueError:
    logging.error("Exception occurred", exc_info=True)  # Noncompliant

Compliant solution

import logging

try:
    raise ValueError("Invalid value")
except ValueError:
    logging.exception("Exception occurred")

Resources

Documentation

• Python logging documentation - logging.exception() - Official Python documentation for the logging.exception() method
• Python logging HOWTO - Python’s official guide to using the logging module effectively