[Laszlo-dev] For Review: Change 20071107-jcrowley-O Summary: Deferring initstage of a Grid results problems

[J Crowley]

Hrmm.  Well, in these cases, I'm trying to make sure that our own  
components don't automatically generate "p is null" errors, since they  
probably shouldn't be.  It doesn't seem to cause an issue with  
functionality, but it's probably a good idea to get rid of Debugger  
warnings emanating from our own stuff, I think.

It's a useful warning, and I think it's definitely necessary to let  
someone know that their data requests are likely going wrong  
somewhere, or that they're requesting data that isn't there.  It could  
*possibly* be maybe a little more verbose about why the message is  
appearing (e.g. "p returned null - requested xpath not found" or  
something).

On Nov 7, 2007, at 2:49 PM, P T Withington wrote:

> Do we need a different protocol here, where you should be allowed to  
> make a query when 'p is null' and just get back undefined?
>
> Or is it always an error to try to make a query when 'p is null'?
>
> Can we have a better error message, so that a mere mortal might know  
> what 'p is null' means to them?  What they might do to address the  
> problem?
>
> On 2007-11-07, at 14:30 EST, J Crowley wrote:
>
>> Change 20071107-jcrowley-O by jcrowley at DoctorManhattan.mshome.net  
>> on 2007-11-07 14:20:42 EST
>>   in /Users/jcrowley/src/svn/openlaszlo/trunk-g
>>   for http://svn.openlaszlo.org/openlaszlo/trunk
>>
>> Summary: Deferring initstage of a Grid results problems
>>
>> New Features:
>>
>> Bugs Fixed: LPP-4116 - Deferring initstage of a Grid results
>> 	problems
>>
>> Technical Reviewer: pbr
>> QA Reviewer: max
>> Doc Reviewer:
>>
>> Documentation:
>>
>> Release Notes:
>>
>> Details: The description provided in the bug was
>> 	no longer reproducible.  I believe someone
>> 	at some point added a check to make sure
>> 	datapath existed before trying to call
>> 	xpathQuery().  However, there was still an
>> 	issue with "p is null" showing up, so I
>> 	added a check to make sure that didn't
>> 	happen.
>>
>> Tests: Run the following in DHTML and Flash:
>>
>> <canvas>
>>   <dataset name="multidata">
>>       <results>
>>           <info first="Bill" last="Henders" phone="1-888-888-8888"  
>> hat="no"/>
>>           <info first="Joan" last="Liszt" phone="1-888-877-8778"  
>> hat="no"/>
>>           <info first="Michael" last="Banyon"  
>> phone="1-777-778-7788" hat="yes"/>
>>           <info first="Sylvia" last="Conners"  
>> phone="1-877-878-8877" hat="no"/>
>>           <info first="Josef" last="Regnola" phone="1-887-778-8787"  
>> hat="no"/>
>>           <info first="Olivia" last="Estaban"  
>> phone="1-778-778-7788" hat="yes"/>
>>       </results>
>>   </dataset>
>>
>>   <window title="Defer Test" width="400" height="150"
>>       name="win1">
>>       <grid id="vscgrid" contentdatapath="multidata:/results/*"  
>> bgcolor0="0x00FF00" bgcolor1="0xFF0000"
>>           width="${immediateparent.width}" height="$ 
>> {immediateparent.height}" initstage="defer">
>>           <gridtext editable="false" textalign="center"  
>> datapath="@first">
>>               First Name
>>           </gridtext>
>>           <gridtext editable="false" textalign="center"  
>> datapath="@last">
>>               Last Name
>>           </gridtext>
>>           <gridtext editable="false" textalign="center"  
>> datapath="@phone">
>>               Phone Number
>>           </gridtext>
>>           <gridtext editable="false" textalign="center"  
>> datapath="@hat">
>>               Wears Hat
>>           </gridtext>
>>       </grid>
>>   </window>
>>
>>   <window title="poke" layout="axis:'y'" x="${win1.width+10}">
>>       <button text="Complete Instantiation">
>>           <method event="onclick">
>>               vscgrid.completeInstantiation();
>>           </method>
>>       </button>
>>   </window>
>>
>> </canvas>
>>
>> Click the button.  Note that there is no "p is null" error, nor is  
>> there
>> 	(as described in the bug) an error about xpathQuery(), and that
>> 	the alternating colors work as before.
>>
>> Files:
>> M      lps/components/base/basegridrow.lzx
>>
>> Changeset: http://svn.openlaszlo.org/openlaszlo/patches/20071107-jcrowley-O.tar
>