[python] Why is "except: pass" a bad programming practice?

Simply put, if an exception or error is thrown, something's wrong. It may not be something very wrong, but creating, throwing, and catching errors and exceptions just for the sake of using goto statements is not a good idea, and it's rarely done. 99% of the time, there was a problem somewhere.

Problems need to be dealt with. Just like how it is in life, in programming, if you just leave problems alone and try to ignore them, they don't just go away on their own a lot of times; instead they get bigger and multiply. To prevent a problem from growing on you and striking again further down the road, you either 1) eliminate it and clean up the mess afterwards, or 2) contain it and clean up the mess afterwards.

Just ignoring exceptions and errors and leaving them be like that is a good way to experience memory leaks, outstanding database connections, needless locks on file permissions, etc.

On rare occasions, the problem is so miniscule, trivial, and - aside from needing a try...catch block - self-contained, that there really is just no mess to be cleaned up afterwards. These are the only occasions when this best practice doesn't necessarily apply. In my experience, this has generally meant that whatever the code is doing is basically petty and forgoable, and something like retry attempts or special messages are worth neither the complexity nor holding the thread up on.

At my company, the rule is to almost always do something in a catch block, and if you don't do anything, then you must always place a comment with a very good reason why not. You must never pass or leave an empty catch block when there is anything to be done.

Examples related to python

programming a servo thru a barometer Is there a way to view two blocks of code from the same file simultaneously in Sublime Text? python variable NameError Why my regexp for hyphenated words doesn't work? Comparing a variable with a string python not working when redirecting from bash script is it possible to add colors to python output? Get Public URL for File - Google Cloud Storage - App Engine (Python) Real time face detection OpenCV, Python xlrd.biffh.XLRDError: Excel xlsx file; not supported Could not load dynamic library 'cudart64_101.dll' on tensorflow CPU-only installation

Examples related to exception

Connection Java-MySql : Public Key Retrieval is not allowed How to print an exception in Python 3? ASP.NET Core Web API exception handling Catching FULL exception message How to get exception message in Python properly What does "Fatal error: Unexpectedly found nil while unwrapping an Optional value" mean? what does Error "Thread 1:EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)" mean? Argument Exception "Item with Same Key has already been added" The given key was not present in the dictionary. Which key? sql try/catch rollback/commit - preventing erroneous commit after rollback

Examples related to error-handling

must declare a named package eclipse because this compilation unit is associated to the named module Error:Failed to open zip file. Gradle's dependency cache may be corrupt What does 'index 0 is out of bounds for axis 0 with size 0' mean? What's the source of Error: getaddrinfo EAI_AGAIN? Error handling with try and catch in Laravel What does "Fatal error: Unexpectedly found nil while unwrapping an Optional value" mean? Raise error in a Bash script Javascript Uncaught TypeError: Cannot read property '0' of undefined Multiple values in single-value context IndexError: too many indices for array

Examples related to try-catch

Try-catch block in Jenkins pipeline script Error handling with try and catch in Laravel sql try/catch rollback/commit - preventing erroneous commit after rollback IsNumeric function in c# Why is "except: pass" a bad programming practice? EOFException - how to handle? How to efficiently use try...catch blocks in PHP How to return a value from try, catch, and finally? Multiple try codes in one block Catch KeyError in Python