Re: [HACKERS] [sqlsmith] Crash in tsquery_rewrite/QTNBinary

Artur Zakirov <a.zakirov@postgrespro.ru> writes:
> 2016-12-07 9:06 GMT+03:00 Andreas Seltenreich <seltenreich@gmx.de>:
>> the following query crashes master as of 4212cb7.

> It happens because 'I' is stop word and substitute query becomes
> empty. And for queries above we need recursive dropvoidsubtree()
> function. Without this patch this function cleans only first level of
> tree. And query above becomes: '6 | void'.

> Firstly I made recursive dropvoidsubtree(). But attached patch cleans
> query tree in dofindsubquery() to avoid extra tree scan.

This patch looks good to me.  I have to admit that I'd been suspicious
of dropvoidsubtree() the last time I looked at this code, but I didn't
have adequate reason to touch it.  Pushed with some minor comment
adjustments.
        regards, tom lane