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

Marcos Douglas md at delfire.net
Mon Jul 9 14:02:46 CEST 2012

On Mon, Jul 9, 2012 at 5:27 AM, Reinier Olislagers
<reinierolislagers at gmail.com> wrote:
> 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.


Marcos Douglas

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