[Lazarus] RE : Propose: dont try to open TDBLookup* ListSourceautomatically

[Reinier Olislagers]

On 9-7-2012 10:00, Ludo Brands wrote:
> 
>> Currently the db lookup controls tries to open the dataset linked to 
>> ListSource if is closed at lookup initialization.
>>
> 
> You probably guessed it but I'm voting for removing this feature. Opening of
> datasets and establishing database connections behind the back of the
> programmer is always a bad idea.  
> 
> The try open when loaded (streamed), even in the fixed version, has also the
> nasty side effect of not being deterministic. A programmer can't easily
> influence the loading order of components and a change in the order will
> change the behavior of the program.  The fix in 22337 solves the exception
> but not the unpredictable behavior. If the link dataset and connection are
> loaded before the dblookup it will open the dataset, else it won't. So your
> program can start up with (some) dblookups pre-loaded or not. 
> 
> We shouldn't support users counting on unpredictable behavior. 
> 
Totally agreed.