FPs and SA 3.2.0

Tue May 22 09:22:12 IST 2007

Yeah apologies Paul I was tired :(  I am having a play around with the code
at the moment. What would happen though if a RBL was purely numbers ie.
12345 ?

On Mon, 21 May 2007 21:23:40 +0100, Julian Field
<MailScanner at ecs.soton.ac.uk> wrote:
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> Paul Bijnens wrote:
>> On 2007-05-21 17:10, Julian Field wrote:
>>   
>>> Paul Bijnens wrote:
>>>     
>>>> On 2007-05-16 17:41, Julian Field wrote:
>>>>       
>>>>> I'll put it in the main codebase then. Perl has some very subtle bugs
> in 
>>>>> it...
>>>>>     
>>>>>         
>>>> I believe I don't need to teach perl to Julian (rather the other way
>>>> around :-) ), but anyway...
>>>>       
>>>     
>>>>>>>>       
>>>>>>>>           
>>>>>>>>               
>>>>>>>>>   # JKF 3/10/2005
>>>>>>>>>   my $temp = @HitList;
>>>>>>>>>   $temp = $temp + 0;
>>>>>>>>>   $temp = 0 unless $HitList[0] =~ /a-z/i;
>>>>>>>>>   return ($temp, join(', ', @HitList));
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> Let's see if that helps. According to the book, the 2 middle
> lines
>>>>>>>>> shouldn't be needed at all.
>>>>>>>>>             
>>>>>>>>>                 
>>>> To me this seems like the array @HitList contains an empty or undef
>>>> value.  The match against "/[a-z]/i"   (or was that really intended
>>>> "/a-z/i"??)
>>>>       
>>> No, your version would match against any string that contained the 
>>> string "a-z" in it (in upper or lower case).
>>>     
>>
>> Excuse me :-) but "/a-z/i" is your version and that will search for
>> a string "a-z" lower or upper case.  My version, "/[a-z]/i", will match
>> a name with at least one letter in it.  Which is what you're trying to
>> do, I believe.
>>   
> It appears I owe you a rather large apology :-(
> Sorry!
> Many thanks for pointing out the error in my code. I have fixed it and 
> put out a new beta with it fixed.
> 
>> You're effectively removing any RBL hits now, which is the main reason
>> why no more FP's got hit by the current beta tester(-s? -- only one
>> person as far I see had the problem).
>>
>> http://lists.mailscanner.info/pipermail/mailscanner/2007-May/073331.html
>>
>> I'm still interested in the exact list of RBLs in his config.
>> Does it happen when 1 list is added? Two?  Some particular list only?
>>
>>
>>   
>>>>  just hides the source of the real error: getting an empty
>>>> value for RBL name.
>>>>       
>>> If I printed the string of @HitList it turned out to have no contents, 
>>>     
>>
>> How?    Something like:
>>
>>     @HitList = ( "" );	# somehow this ended up in the list
>>     $temp = @HitList;
>>     warn("HitList contains $temp entries: '@HitList'\n");
>>
>> No (visible) contents, but still one element in the array.
>>
>>
>>   
>>> so the scalar of it should have been zero. I have seen the problem of 
>>> "0" not always equaling zero a few other times, hence the addition of 
>>> zero to it to try to fix it, which has normally fixed the problem 
>>>     
>>
>> You can have that problem with "" or undef, acting as 0 in calculations
>> but not showing up as a "0" when printed. Indeed fixed by explicitly
>> converting to number by adding "+ 0".
>>
>>   
>>> elsewhere. The new modification has only been recently needed, the code
> 
>>> has worked perfectly well for years (the previous version was very old 
>>> code). If it had been needed before, people would have been complaining
> 
>>> loudly about this for the past few years, and they haven't been. So if 
>>> the start of the list doesn't contain a letter (all RBL names must 
>>> contain at least 1 letter or they wouldn't work) then the list must 
>>> actually be empty, so I force it to return zero.
>>>     
>>
>> So we have to find out where the list element comes from that does
>> not contain a letter, but is empty instead.  Instead of covering up the
>> bug here.  (Still not convinced it is a perl bug.)
>> Maybe most people use some RBLs at the MTA-level to block the incoming
>> mail completely and/or use other RBLs in SA for scoring, and let the
>> spam list entry in MailScanner empty.  Or the bug happens only on
>> a timeout, like suggested in the OP problem, or only for certain
>> combinations of timeout values, etc, etc.
>>
>>
>>   
>>>> Now finding out where the empty value is coming from, is -- at my
>>>> current understanding of the code -- not yet successful.
>>>>       
>>> Yes. I have another demo of a Perl bug which I'll post for you if you 
>>> like. Perl is not bug-free.
>>>     
>>
>> Sure not.  But, speaking for myself, it's usually in my own
>> programs, and not in the perl compiler, that I find the bugs.  :-)
>>   
> Agreed. But I have found the '$n=$n+0' trick solve a few problems in the 
> past. Bugs that appeared on 1 user's system that I could not reproduce 
> on my own systems. Adding 0 fixed it.
> 
> But yes, on the other hand, they have been rare (I think there's 2 in 
> the whole of MailScanner, the most annoying was the spam score returned 
> by SpamAssassin. It was generating 'not spam' reports where it clearly 
> printed a spam score greater than the threshold. Add 0 to the number and 
> then do the comparison again, and it produced the desired result.)
> 
> 
> Jules
> 
> - -- 
> Julian Field MEng CITP
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