Re: bison bug.

[James Harris]

Yes this is a real case. I ran across this bug while developing
software. While I can not publish the code that exposed the bug I
generated a file which was similar enough to produce the same bug.  I have
started to document the bug and will follow up the report once I have some
more information. As you can see from the grammar 255 rules aren't that
many, while the number of tokens may be large.. I dont belive its so large
to be useless. 255 rules looks a lot like a magic number, that needs to be
fixed.


On 22 Dec 2001, Akim Demaille wrote:

> 
> | This isn't the only bug I have run across in bison, but I belive they are
> | all symptoms of the same bug. 
> 
> I don't think so, 1.30 has a lot of problems.
> 
> | I belive a some internal variable is to
> | small. As you can see the number 256 rules is rather telling. 255 is
> | acceptable, 256 produces the bug.
> 
> Your test case doesn't make it clear exactly what is the problem?  The
> total number of rules only, or is the number of symbols on the RHS
> relevant?
> 
> Whatever the answer, I agree this is a bug.  Nonetheless, it is not
> clear how to fix it: die with dignity diagnosing an overflow, or try
> to work with such grammars?
> 
> In other words: is your test case realistic of some real condition
> uses, or just a torture test?
>