Panic in Python

In Python, we typically use exceptions to handle unexpected errors or situations. The equivalent of a panic in Python is raising an exception. Here’s an example:

import os

def main():
    # We'll use exceptions throughout this site to check for
    # unexpected errors. This is the only program on the
    # site designed to raise an exception.
    raise Exception("a problem")

    # A common use of exceptions is to abort if a function
    # returns an error value that we don't know how to
    # (or want to) handle. Here's an example of
    # raising an exception if we get an unexpected error when creating a new file.
    try:
        with open("/tmp/file", "w") as f:
            pass
    except IOError as e:
        raise Exception(f"Couldn't create file: {e}")

if __name__ == "__main__":
    main()

Running this program will cause it to raise an exception, print an error message and traceback, and exit with a non-zero status.

When the first exception in main is raised, the program exits without reaching the rest of the code. If you’d like to see the program try to create a temp file, comment out the first raise statement.

$ python panic.py
Traceback (most recent call last):
  File "panic.py", line 13, in <module>
    main()
  File "panic.py", line 6, in main
    raise Exception("a problem")
Exception: a problem

Note that in Python, it’s idiomatic to use exceptions for handling many errors, unlike some languages which might use error-indicating return values. Python’s try/except blocks allow for more granular error handling and recovery.

The Python equivalent of a panic (raising an exception) can be caught and handled using try/except blocks, allowing for more flexible error handling compared to Go’s panic which typically leads to program termination.