[Bf-committers] Using assert()?

[Jason W.]

I think one way to think of an assert is as extra documentation of assumptions that you do not want to check for because of efficiency or redundancy reasons.  Like an extra check that goes beyond what the compiler can do for you at compile time.



On Aug 16, 2010, at 10:33 PM, Torsten Rupp <torsten.rupp at gmx.net> wrote:

> Dear Jason,
> 
> thanx for your message.
> 
>> Asserts are not present in release code, so they should never
>> contain code that has side effects.
> 
> Yes, that is true. Asserts are only checks, thus never put something 
> in an assert with a side effect that is missing when the assert would 
> not be there which is usually the case for the non-debug version on 
> an application.
> 
>> An assert should never be used for ordinary error conditions that
>> need to be checked for delt with by the program.
> 
> I agree, too. Asserts are not for error handling, but for checking if 
> the program still have a consistent state and is doing what was 
> intented to do. If something could go wrong in the normal program 
> behavior, e. g. open a file fail, this must be handled by some useful 
> code which does not simple stop the application (what an assert 
> always do). Though I think:
> 
> - everything what could go wrong e. g. because of a user interaction, 
> must be handled by the program, even the user may misuse the program 
> totally.
> 
> - everything which should never go wrong (the theory), but may go 
> wrong for some reason (the reality), should be checked by an assert 
> (the check of a precondition). This even become imho more important 
> if the failure could cause a disastrous result, e. g. a SigSegV, 
> which is usually hard to trace back.
> 
>> Used properly I would almost say you do not need permission to add
>> asserts. I normally add them all over the place.  Unfortunately
>> like you I was nervous about using them when it doesn't seem to be
>> wide spread in Blender, so I refrained.
> 
> Thanx for this clarification. I just wanted to make sure, what is the 
> intention. Thus I will add also asserts() now when this seems to be 
> helpful.
> 
> Torsten