documenting excepetions in Python

[dale_bertrand]

In python, how do I know what exceptions a method could raise? Do I
need to look at the source? I don't see this info in the API docs for
any of the APIs I'm using.

Thanks in advance for your help.

[kyosohma]

On Oct 19, 10:32 am, dale_bertr...@y ahoo.com wrote:

In python, how do I know what exceptions a method could raise? Do I
need to look at the source? I don't see this info in the API docs for
any of the APIs I'm using.

Thanks in advance for your help.

Read the source, run unit tests, etc. If you write your own methods,
you might consider writing tests beforehand: http://en.wikipedia.org/wiki/Test-driven_development

Sometimes the module's docs will tell you the likely return values,
which can help you know what exceptions to look out for.

Mike

[Nikita the Spider]

In article <11************ *********@y27g2 000pre.googlegr oups.com>,
da***********@y ahoo.com wrote:

In python, how do I know what exceptions a method could raise? Do I
need to look at the source? I don't see this info in the API docs for
any of the APIs I'm using.

Hi Dale,
Usually the docs for a method will list the likely exceptions, but
there's no way to know the full list of possible exceptions except by
testing, testing, testing. Obviously, there's always a chance that
there's a test you didn't think of and therefore an exception
unaccounted for. I think this is a less-than-ideal aspect of Python but
I don't have a suggestion on how to improve it.

Good luck

--
Philip
http://NikitaTheSpider.com/
Whole-site HTML validation, link checking and more

[Bruno Desthuilliers]

da***********@y ahoo.com a écrit :

In python, how do I know what exceptions a method

s/method/callable/

A method is only a thin wrapper around a function, and functions are
just one kind of callable object (classes are another, and you can
define your own...)

could raise?

Practically speaking, you can't. Since an unhandled exception bubbles up
the call stack, there's no reliable way to know what exception could
happen when calling a function. Now there are quite a lot of
'exceptions' you can expect in some situations - like IOError when
dealing with files, etc.

Do I
need to look at the source?

Would be impractical. Trying to spot each and every exception that could
happen in a real-world call stack is a waste of time IMHO. Just deal
with the ones that:
1/ could obviously happen here (like : a missing key in a dict, a
non-(existing|reada ble|writable) file, etc,
2/ you can handle at this level

Else, just learn to live with the fact that shit happens.

I don't see this info in the API docs for
any of the APIs I'm using.

Indeed. Most of the time, it would be just meaningless.