Improve handling of invalid input in dlls/comctl32/datetime.c

[James McKenzie]

Nikolay Sivov wrote:
> On 12/26/2009 00:47, James McKenzie wrote:
>> Nikolay Sivov wrote:
>>   
>>> Why? There's no default case, treat is as 'if () {} else if () {}
>>> etc.'.
>>> It's the same thing to have explicit initializers for all local
>>> variables even if I don't use it before
>>> set some value. It's a pollution, especially if used to silence
>>> analyzer warnings.
>>>      
>> Nikolay:
>>
>> Things can and do go 'wrong'.  For instance, you build on Linux, I build
>> on a Mac.  Sometimes the ported programs from UNIX can and will do
>> 'strange' things.  If you don't have a method to know that there is an
>> error, then you go about blaming Wine when it is a poor program port.
>>    
> That's a Mac build environment then. If there's no real problem now,
> there's no point to add such
> workarounds, if it is then a compiler should be fixed.
With this statement, I agree.  I am dealing with a sed issue that causes
the authors.c file in the Wine build to break.  Is this Wine's fault? 
No.  It is a problem outside of the scope of the project.  Would
additional code fix this in Wine, no.
>
>> Also, it is good programming practice to account for the situations you
>> don't expect to encounter and to initialize variables that you will be
>> using.  This is not a 'just in case' thing, it can help when program
>> errors occur to see where in the code an expected value did or did not
>> happen.
>>    
> It also hides things sometimes and adds noops.
Agreed.  But if there is code we should NEVER reach, maybe it is good to
tell someone.  That is why I like defaults in cases where the other
values should be the only values reached.  If you are doing checks
before the call that invokes the case, then there is no need for the
default case as erroneous data is already checked for.  I've used that
as well.
>> I know, it looks like pollution, but when code goes wrong, and it will,
>> this makes troubleshooting much easier.
> It will go wrong only due a build problem or something like that, it
> such case you can't trust a line.
I trust NOTHING.  That includes this computer.  It can and has failed on
me.  However, you can do things, like tested backups that can mitigate
failures...
>>    I know this from running
>> Quality Assurance testing for many years and coding myself.  My
>> programming instructor deducted grade points for failing to handle error
>> and other unexpected conditions.
>>
>>    
> Ok, in theory yes, but I'm speaking about a particular piece.
Thank you.  
> Anyway, my point is that code in subject is clear and can't cause
> problems patch tries to predict -
> it's the same condition used twice.
>
> I really have nothing to add here, let's see Alexandre's opinion.
>
Yes, AJs opinion is the 'last word' on code entering Wine.  I've seen
code that I would not pass get into the project base and code I would
have passed get rejected.  AJs long history with this project gives him
knowledge that some of us don't and will not have.

I agree that we should see what AJ has to say about this particular
section of code.

James McKenzie