Remove explicit catching of SystemExit or Keboardinterrupt

[Krzysztof Jurewicz]

In assertXMLEqual and assertXMLNotEqual methods, test result is determined as following:

try:
    result = compare_xml(xml1, xml2)
except Exception as e:
    standardMsg = 'First or second argument is not valid XML\n%s' % e
    self.fail(self._formatMessage(msg, standardMsg))

Because of that, KeyboardInterrupt and SystemExit raised during XML comparison are suppressed.

[Krzysztof Jurewicz]

I’ve created a pull request: ​https://github.com/django/django/pull/1992

[Baptiste Mispelon]

Hi,

KeyboardInterrupt and SystemExit are not caught by an except Exception clause (that's because they inherit from BaseException):

>>> issubclass(SystemExit, Exception)
False
>>> issubclassKeyboardInterrupt, Exception)
False

The code change you proposed would have no effect.

[Krzysztof Jurewicz]

Indeed, I was misleaded, by this legacy code: ​https://github.com/django/django/blob/3c10d1e64faeb67b41e7aa501b21252e357a4564/django/test/testcases.py#L178 . Since we don’t support Python 2.4 and lower anymore, such parts of code can be removed, so I’m reopening the ticket.

[Baptiste Mispelon]

Indeed, that is not necessary anymore. Good catch.

A cleanup of the whole codebase to remove this outdated pattern would be nice.

I'm accepting the ticket on this basis (and changing the description accordingly).

[Krzysztof Jurewicz]

Ok, I’ve opened another pull request: ​https://github.com/django/django/pull/1993 . I’ve grepped the whole codebase, but found this pattern only in one file.

[Baptiste Mispelon <bmispelon@…>]

In 7a0a3a64a827480c737060bcd5af9af25c3b3c15:

Fixed #21509 -- Removed dead exception catching code.

Since Python 2.5, KeyboardInterrupt and SystemExit are not subclasses of
Exception, so explicitly reraising them before the “except Exception” clause
is not necessary anymore.