Re: [Qemu-devel] [PATCH 1/4] qjson: Improve debugging

[Anthony Liguori]

On 02/05/2010 11:14 AM, Markus Armbruster wrote:
> > Run time asserts are a terrible way to deal with reasonably expected errors.
> >      
> Yes.  But what's reasonably expected entirely depends on the contract
> between the function and its callers.
>
> I think we need a function that cannot fail and shouldn't used with
> untrusted arguments (for what it's worth, that's how we use
> qobject_from_jsonf() now).  Having related functions with different
> contracts is fine with me.
>    

I think the key point is that if we're going to establish these 
contracts, it must be obvious.

A reasonable programmer is going to assume that if a function can return 
a NULL, it can possibly return an error.  If you want to deviate from 
those semantics, you either have to name the function appropriately or 
put a big comment above the declaration explaining the semantics.

Regards,

Anthony Liguori