[Laszlo-dev] For Review: Change 20090206-dda-z Summary: With catcherrors=true, disable try/catch/closure when 'arguments' is used.

[Donald Anderson]

Committed.  Future work is in LPP-7732 assigned to me for now.

On Feb 7, 2009, at 2:33 PM, P T Withington wrote:

> I'm approving this because it appears safe and we would like it in  
> 4.2.0.1.
>
> I think we should file an improvement to re-address this in 4.2.1,  
> using something more like the Debug.evalCarefully technology, which  
> is used in DHTML.  The evalCarefully approach would be to wrap the  
> potentially erring function at the call site, where the analysis of  
> free references will be much simpler, hence the creation of a  
> closure that does not perturb those references will be simpler too.
>
> We can analyze whether putting the try/catch inline at call sites  
> rather than in function  bodies causes too much code bloat and  
> measure that against the speed penalty of using an evalCarefully  
> subroutine instead.
>
> Please check in this fix and create a new bug with the above  
> suggestions.
>
> On 2009-02-06, at 22:48EST, Donald Anderson wrote:
>
>> Change 20090206-dda-z by dda at lester-2.local on 2009-02-06 22:16:07  
>> EST
>>   in /Users/dda/laszlo/src/svn/openlaszlo/trunk-g/test
>>   for http://svn.openlaszlo.org/openlaszlo/trunk/test
>>
>> Summary: With catcherrors=true, disable try/catch/closure when  
>> 'arguments' is used.
>>
>> New Features:
>>
>> Bugs Fixed: LPP-7721 [xml-rpc is not working when  
>> "compiler.swf9.catcherrors=true"]
>>
>> Technical Reviewer: ptw (pending)
>> QA Reviewer: (pending)
>> Doc Reviewer: (pending)
>>
>> Documentation:
>>
>> Release Notes:
>>
>> Details:
>>   ** for consideration in 4.2.0.1
>>
>>   'arguments' refers to the arguments passed to the enclosing  
>> function, and allows some
>>   clever examination of arguments dynamically.  With  
>> catcherrors=true, an additional
>>   function closure is wrapped around each function within a try/ 
>> catch, and the extra
>>   function thwarts the use of 'arguments' within the body of the  
>> original function.
>>   To avoid such problems, we disable catcherrors for any functions  
>> that refer to
>>   the magic 'arguments'.  This allows us to remove the workaround  
>> pragmas added
>>   to lps/components (which also disabled catcherrors, but for  
>> specific functions)
>>   As a bonus, smokecheck now passes with catcherrors enabled.
>>
>>   It's true that now a small percentage of functions will not have  
>> the try/catch wrapping
>>   that used to have it.  However, such functions should be relative  
>> rare, will probably
>>   be in component code rather than user code, and if in user code,  
>> would probably not
>>   be a top level function.  Any such functions that are not top  
>> level functions would
>>   will be under the control of a higher level try/catch block.   
>> Finally, any such functions
>>   that we now don't wrap may well have been broken under the  
>> previous implementation.
>>
>> Tests:
>> With catcherrors=true:
>>     {smokecheck,lzpix,weather} x {swf8,swf9,dhtml}
>> Verified that testcase submitted with LPP-7721 works.
>> Verified that Tucker's test case from LPP-7514 works. (illustrating  
>> that an error in a function
>>   is ignored, allowing the function to return 'normally' and  
>> execution to continue).
>>
>> Files:
>> M      WEB-INF/lps/server/src/org/openlaszlo/sc/ 
>> JavascriptGenerator.java
>> M      lps/components/rpc/xmlrpc.lzx
>> M      lps/components/rpc/javarpc.lzx
>> M      lps/components/rpc/soap.lzx
>>
>> Changeset: http://svn.openlaszlo.org/openlaszlo/patches/20090206-dda-z.tar
>>
>>
>>
>> --
>>
>> Don Anderson
>> Java/C/C++, Berkeley DB, systems consultant
>>
>> voice: 617-306-2057
>> email: dda at ddanderson.com
>> www: http://www.ddanderson.com
>>
>>
>>
>>
>>
>


--

Don Anderson
Java/C/C++, Berkeley DB, systems consultant

voice: 617-306-2057
email: dda at ddanderson.com
www: http://www.ddanderson.com





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