What's the best way to minimize the need of run time checks?

[Christian Gollwitzer]

Am 12.08.16 um 11:58 schrieb BartC:
> On 12/08/2016 10:45, Chris Angelico wrote:
>> On Fri, Aug 12, 2016 at 7:38 PM, BartC <bc at freeuk.com> wrote:
>>> You can be too dynamic. Take an example like this:
>
>>>  d.yaer=1999
>>>
>>>  print (d.day,d.month,d.year)
>
>>> This would never get past a static language nor some that also have
>>> dynamic
>>> types.
>>
>> Nor will it get past a lot of linters. Or unit tests. There are other
>> solutions.
>
> How would a linter know that you didn't /want/ to create a new attribute
> called 'yaer'?

It is possible to create an attribute outside of the class, but it is 
unusual. I tried your example using pylint. It gives me:

W:  9, 0: Attribute 'yaer' defined outside __init__ 
(attribute-defined-outside-init)

Granted, pylint also spits an enormous amount of other stylistic 
warnings about spaces and "wrong" indents which, strangely, have the 
same weight "warning" as this bug, so it's a bit hard to find.

A linter from another language I use also spell-checks variable names, 
i.e. if it finds two variables with suspiciously similar names, it 
reports it. Of course the linter never knows for sure, it can only give 
warnings.

	Christian