Are there tools that can spot errors like this one?

Question

I found the following mistake in my code this week:

import datetime

d = datetime.date(2010,9,24)
if d.isoweekday == 5:
    pass

Yes, it should be d.isoweekday() instead.

I know, if I had had a test-case for this I would have been saved. Comparing a function with 5 is not very useful. Oh, I'm not blaming Python for this.

My question: Are there tools that can spot errors like this one?

Answer 1

Check out pylint it may be able to get that. It does find many errors.

Answer 2

You can use a debugger but I am not sure whether that would highlight this kind of error.

You can check this link as well: http://stackoverflow.com/questions/477193/suggestions-for-python-debugging-tools

Answer 3

Well, this is not an error in python per se because in Python, the functions are callable objects. You can make any object callable by implementing __call__. So d.isoweekday == 5 is valid statement. This will be False.

As for other errors, i suggest checking out pyflakes - http://divmod.org/trac/wiki/DivmodPyflakes

Answer 4

As an alternative, most Python projects are unit tested and system tested. If you have both (or even just unit tests) you'll find your problem along with pretty much any other issue.

As dekomote said, this is syntaxically valid. Python is not statically typed so this cannot be caught as an error. At most it could be a warning.

EDIT: Python is strongly typed just the type is checked at run time.