[antlr-interest] Serious Bug when using BitSetgeneration

Geir Ove Skjaervik geiroves at online.no
Wed Nov 9 09:43:55 PST 2005


Hello,

First of all, I have stated that I WILL try to provide an example that
reproduces the error. I am currently at a conference in Malmø Sweeden
and do not have the time nor opportuinity to do that; It will surely be
time consuming.

Secondly, I sincerely hope you are NOT Serious when you say: QUOTE:
<<Also you seem to be the only one that ran into this so far>>  Well,
someone surely must be the first one to report / encounter a bug, but in
your book that means neglecting it? How do you know that others haven't
encountered this bug? It took me 2 at least 2 months of trying to
rewrite code since I thought it was me, when it was ANTLR all the time.

Thrirdly, the workaround is not good performance wise.

What's worst, is that as long as the Bug is there, you really do not
knows when it bites you: The only way to find out, is to try BOTH with
and without Bitsets whenever a piece of code does not parse as expected.
THAT IS NOT a good solution timewise, and ANTLR is supposed to save us
time, isn't it?



Geir Ove

-----Original Message-----
From: Ric Klaren [mailto:ric.klaren at gmail.com] 
Sent: 9. november 2005 15:52
To: Geir Ove Skjaervik
Cc: 'ANTLR Interest'
Subject: Re: [antlr-interest] Serious Bug when using BitSetgeneration


Hi,

Geir Ove Skjaervik wrote:
> Just one more comment on this Bug. It is ** clearly ** a bug, since
> ANTLR does work correctly when BitSets are NOT used. I find it strange

> that this Bug  seems to be passed in almost silence: I would think it 
> to be rather serious to have a "sleeping" bug that may come and bite 
> you any time you encounter the right conditions.

1) As you yourself mentioned there is a workaround. Also you seem to be
the only one that ran into this so far.
2) We cannot reproduce the bug since you don't supply us with the
necessary information to find it: e.g. a clear piece of code that
demonstrates it. I tinkered a bit with the example code you provided but
cannot reproduce it. Terence spent time on it and he cannot reproduce
it. So it's apparently something deeper down in your grammar.

Did you try older antlr versions on the code to see whether it was
introduced in one of the last releases, this might help us narrowing
down where to look? Running the grammar on older antlr's should not take
long.

> Terrence asked me to try to produce a small grammar example to try to
> reproduce the problem. I will as soon as time on my project permits 
> it.

> BUT I would think it is equally IMPORTANT for the ANTLR team to try to
> hunt down this ** serious ** bug. It is nice that ANTLR 3.0 is under 
> development, but we sure need a strong ** core ** technology that 
> won't fail.

Hunting bugs blindly is a waste of time. FYI all ANTLR developers have
fulltime jobs not involving ANTLR. Looking at antlr2 code without
knowing what triggers a bug is useless -> provide a good bugreport that
demonstrates the problem!

For me this bug is on ice untill *you* produce a good defect report.

Shouting at us will really not make things go faster. If the speedloss
is a big issue then you should check with your management to get the
time to help us track down this bug. Taking out your stress on us will
not help you.

Cheers,

Ric





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