[Bioperl-l] For CVS developers - potential pitfallwith "returnundef"

[Hilmar Lapp]

I agree. Thanks to Torsten for the audit and Chris for stepping up.

	-hilmar

On May 31, 2006, at 6:55 AM, Heikki Lehvaslaiho wrote:

> In my opinion the sooner the bugs get exposed the better. It is  
> much more
> likely that there is a well hidden bug caused by assigning  
> accidentally undef
> into an one element array that someone intentionally writing code that
> expects that behaviour!
>
> I removed (but did not commit yet) all undefs from my old  
> Bio::Variation code
> and could not see any differences in the test output.
>
> Let's remove them!
>
> 	-Heikki
>
> On Tuesday 30 May 2006 23:40, Chris Fields wrote:
>> Agreed, though I think these changes should be implemented at some  
>> point
>> (Conway's argument here makes sense and it is nice for Torsten to  
>> check
>> this out).  If proper tests are written then any changes resulting in
>> errors should be picked up by checking the appropriate test suite,  
>> though I
>> know it doesn't absolutely guarantee it.  ; P
>>
>> Chris
>>
>>> -----Original Message-----
>>> From: bioperl-l-bounces at lists.open-bio.org [mailto:bioperl-l-
>>> bounces at lists.open-bio.org] On Behalf Of Rutger Vos
>>> Sent: Tuesday, May 30, 2006 1:53 PM
>>> To: bioperl-l at lists.open-bio.org
>>> Subject: Re: [Bioperl-l] For CVS developers - potential pitfallwith
>>> "returnundef"
>>>
>>> Although I agree with the sentiment of following PBP, I'm not so  
>>> sure
>>> changing 'return undef' to 'return' *now* will fix any bugs without
>>> introducing new, subtle ones.
>>>
>>> Chris Fields wrote:
>>>> Torsten,
>>>>
>>>> Any way you can post a list of some/all of the offending lines or
>>>
>>> modules?
>>>
>>>> Sounds like something to consider, but if the list is as large  
>>>> as you
>>>
>>> say we
>>>
>>>> made need something (bugzilla? wiki?) to track the changes and make
>>>> sure they pass tests; I'm sure a large majority will.
>>>>
>>>> I'm guessing Jason would want this somewhere on the project  
>>>> priority
>>>
>>> list or
>>>
>>>> bugzilla, with a link to the actual list, but I'm not sure.  Maybe
>>>> start
>>>
>>> a
>>>
>>>> page on the wiki for proposed code changes?
>>>>
>>>> Chris
>>>>
>>>>> -----Original Message-----
>>>>> From: bioperl-l-bounces at lists.open-bio.org [mailto:bioperl-l-
>>>>> bounces at lists.open-bio.org] On Behalf Of Torsten Seemann
>>>>> Sent: Tuesday, May 30, 2006 3:19 AM
>>>>> To: bioperl-l at lists.open-bio.org
>>>>> Subject: [Bioperl-l] For CVS developers - potential pitfall with
>>>>> "returnundef"
>>>>>
>>>>> FYI Bioperl developers:
>>>>>
>>>>> I just audited the bioperl-live CVS and found about 450  
>>>>> occurrences of
>>>>> "return undef".
>>>>>
>>>>> Page 199 of "Perl Best Practices" by Damian Conway, and this URL
>>>>> http://www.perl.com/lpt/a/2006/02/23/advanced_subroutines.html
>>>>> suggest:
>>>>>
>>>>> "Use return; instead of return undef; if you want to return  
>>>>> nothing.
>>>>> If someone assigns the return value to an array, the latter  
>>>>> creates an
>>>>> array of one value (undef), which evaluates to true. The former  
>>>>> will
>>>>> correctly handle all contexts."
>>>>>
>>>>> So I'm guessing at least some of these 450 occurrences *could*  
>>>>> result
>>>
>>> in
>>>
>>>>> bugs and should probably be changed.
>>>>>
>>>>> Your opinion may differ :-)
>>>>>
>>>>> --
>>>>> Dr Torsten Seemann               http://www.vicbioinformatics.com
>>>>> Victorian Bioinformatics Consortium, Monash University, Australia
>>>>>
>>>>> _______________________________________________
>>>>> Bioperl-l mailing list
>>>>> Bioperl-l at lists.open-bio.org
>>>>> http://lists.open-bio.org/mailman/listinfo/bioperl-l
>>>>
>>>> _______________________________________________
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>>>
>>> --
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> Rutger Vos, PhD. candidate
>>> Department of Biological Sciences
>>> Simon Fraser University
>>> 8888 University Drive
>>> Burnaby, BC, V5A1S6
>>> Phone: 604-291-5625
>>> Fax: 604-291-3496
>>> Personal site: http://www.sfu.ca/~rvosa
>>> FAB* lab: http://www.sfu.ca/~fabstar
>>> Bio::Phylo: http://search.cpan.org/~rvosa/Bio-Phylo/
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>
>>>
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>>> http://lists.open-bio.org/mailman/listinfo/bioperl-l
>>
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>
> -- 
> ______ _/      _/_____________________________________________________
>       _/      _/
>      _/  _/  _/  Heikki Lehvaslaiho    heikki at_sanbi _ac _za
>     _/_/_/_/_/  Associate Professor    skype: heikki_lehvaslaiho
>    _/  _/  _/  SANBI, South African National Bioinformatics Institute
>   _/  _/  _/  University of the Western Cape, South Africa
>      _/      Phone: +27 21 959 2096   FAX: +27 21 959 2512
> ___ _/_/_/_/_/________________________________________________________
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-- 
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: Hilmar Lapp  -:-  Durham, NC  -:-  hlapp at gmx dot net :
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