Re: psql crashes found when executing slash commands

Michael Paquier <michael@paquier.xyz> writes:
> On Wed, Jun 06, 2018 at 10:42:41AM +0300, Sergei Kornilov wrote:
>> Hmm. What operating system are you using? Hardware architecture? Do
>> you compile postgresql yourself or install some precompiled packages? 
>> We have tests for psql slash-commands and they are not broken.

> My bet is on an issue with the version of flex used for compilation, and
> that those binaries have been manually compiled.

psql does some, um, interesting stuff with sharing lexer state between
separately-built flex lexers.  I would not be too surprised if it crashes
if you build psqlscan.l and psqlscanslash.l with different versions of
flex, or perhaps even just different flex switches.  So that might be an
avenue to check into.

Another theory is that the OP is using something that's not flex at all,
or is some version we've never seen before, and this coding technique
doesn't work at all with it :-(

            regards, tom lane