Need an example of Python ExceptionGroups

[cclauss]

https://docs.python.org/3/library/exceptions.html#exception-groups (New in Python 3.11)

ExceptionGroups are useful for validating data and telling the user of multiple failures.

For example, if we are examining a string to see if it qualifies as a strong password (#10885) we want to see if it

• is long enough
• not too long
• has lowercase characters
• has uppercase characters
• has acceptable special characters
• does not have unacceptable special characters
• does not have too much repetition

If each of these raised a separate exception then we could use an ExceptionGroup to tell the user all of the problems at once. We could tell them that the proposed password is too short and has no uppercase characters and has a ~ which is an unacceptable special character.

The contribution should solve a normal algorithm problem but should an ExceptionGroup to provide detailed feedback.

[vil02]

Hi @cclauss,

is this something what you are looking for?

fromtypingimportList, Tuple, CallablefromcollectionsimportCounterclassPasswordTooShort(Exception): passclassPasswordTooLong(Exception): passclassNoLowercaseCharacter(Exception): passclassNoUppercaseCharacter(Exception): passclassNoSpecialCharacter(Exception): passclassUnacceptableSpecialCharacter(Exception): passclassTooMuchRepetition(Exception): passdef_check_repetition(password: str, max_repetition: int) ->bool: count=Counter(password) returnany(_>max_repetitionfor_incount.values()) defvalidate_password(password: str) ->None: checks: List[Tuple[Callable[[str], bool], Exception]] = [ (lambdapwd: len(pwd) <8, PasswordTooShort("Password is too short.")), (lambdapwd: len(pwd) >20, PasswordTooLong("Password is too long.")), ( lambdapwd: notany(c.islower() forcinpwd), NoLowercaseCharacter("Password has no lowercase characters."), ), ( lambdapwd: notany(c.isupper() forcinpwd), NoUppercaseCharacter("Password has no uppercase characters."), ), ( lambdapwd: notany(cin"1234567890"forcinpwd), NoSpecialCharacter("Password has no acceptable special characters."), ), ( lambdapwd: any(cin",~@"forcinpwd), UnacceptableSpecialCharacter( "Password has unacceptable special characters." ), ), ( lambdapwd: _check_repetition(pwd, 2), TooMuchRepetition("Password has too much repetition."), ), ] errors= [errorforpredicate, errorinchecksifpredicate(password)] iferrors: raiseExceptionGroup("Password Validation Errors", errors) if__name__=="__main__": try: validate_password("passssw~rd1") exceptExceptionGroupase: forexceptionine.exceptions: print(exception)