Your Web News in One Place

An Interest In:

Web News this Week

Search Archive

Some of Our Sources

View All Sources

Help Webnuz

Referal links:

Sign up for GreenGeeks web hosting
May 18, 2022 02:47 am GMT

Code Smell 132 - Exception Try Too Broad

Exceptions are handy. But should be as narrow as possible

TL;DR: Be as specific as possible when handling errors.

Problems

  • Fail fast principle violation

  • Missing errors

  • False negatives

Solutions

  1. Narrow the exception handler as much as possible

Sample Code

Wrong

import calendar, datetimetry:     birthYear= int(input('Birth year:'))    birthMonth= int(input('Birth month:'))    birthDay= int(input('Birth day:'))    #we don't expect the above to fail    print(datetime.date(int(birthYear), int(birthMonth), int(birthDay)))except ValueError as e:    if str(e) == 'month must be in 1..12':         print('Month ' + str(birthMonth) + ' is out of range. The month must be a number in 1...12')    elif str(e) == 'year {0} is out of range'.format(birthYear):         print('Year ' + str(birthMonth) + ' is out of range. The year must be a number in ' + str(datetime.MINYEAR) + '...' + str(datetime.MAXYEAR))    elif str(e) == 'day is out of range for month':         print('Day ' + str(birthDay) + ' is out of range. The day must be a number in 1...' + str(calendar.monthrange(birthYear, birthMonth)))

Right

import calendar, datetimebirthYear= int(input('Birth year:'))birthMonth= int(input('Birth month:'))birthDay= int(input('Birth day:'))# try scope should be narrowtry:     print(datetime.date(int(birthYear), int(birthMonth), int(birthDay)))except ValueError as e:    if str(e) == 'month must be in 1..12':         print('Month ' + str(birthMonth) + ' is out of range. The month must be a number in 1...12')    elif str(e) == 'year {0} is out of range'.format(birthYear):         print('Year ' + str(birthMonth) + ' is out of range. The year must be a number in ' + str(datetime.MINYEAR) + '...' + str(datetime.MAXYEAR))    elif str(e) == 'day is out of range for month':         print('Day ' + str(birthDay) + ' is out of range. The day must be a number in 1...' + str(calendar.monthrange(birthYear, birthMonth)))

Detection

[X] Manual

If we have a good enough test suite, we can perform mutation testing to narrow the exception scope as much as possible.

Tags

  • Exceptions

Conclusion

We should exceptions as surgical as possible.

Relations

mcsee

Code Smell 26 - Exceptions Polluting

Maxi Contieri Nov 16 '20 2 min read

#oop #exceptions #tutorial #programming

Credits

Foto de Jakob Braun en Unsplash

The primary duty of an exception handler is to get the error out of the lap of the programmer and into the surprised face of the user.

Verity Stob

mcsee

Software Engineering Great Quotes

Maxi Contieri Dec 28 '20 13 min read

#codenewbie #programming #quotes #software

This article is part of the CodeSmell Series.

mcsee

How to Find the Stinky parts of your Code

Maxi Contieri May 21 '21 4 min read

#codenewbie #tutorial #codequality #beginners

Original Link: https://dev.to/mcsee/code-smell-132-exception-try-too-broad-3f8n

Share this article:    Share on Facebook
View Full Article

Dev To

An online community for sharing and discovering great ideas, having debates, and making friends

More About this Source Visit Dev To