Re: Re: [COMMITTERS] pgsql: Fix mapping of PostgreSQL encodings to Python encodings.

On 06/07/12 10:14, Jan Urbański wrote:
> On 06/07/12 10:05, Heikki Linnakangas wrote:
>> In the backend elog routines, there is a global variable
>> 'recursion_depth', which is incremented when an error-handling routine
>> is entered, and decremented afterwards. Can we use a similar mechinism
>> in PLy_elog() to detect and stop recursion?
>
> I guess we can, I'll try to do some tests in order to see if there's an
> easy user-triggereable way of causing PLy_elog to recurse and if not
> then a guard like this should be enough as a safety measure against as
> yet unknown conditions (as opposed to something we expect to happen
> regularly).

Attached is a patch that stores the recursion level of PLy_traceback and
prevents it from running if it's too deep (PLy_traceback is the one
doing heavy lifting, that's why I chose to put the logic to skip running
there).

I tried a few things and was not able to easily invoke the infinite
recursion condition, but I did notice that there are two more encodings
that have different names in Postgres and in Python (KOI8-R and KOI8-U)
and added them to the switch.

There's still trouble with EUC_TW and MULE_INTERNAL which don't have
Python equivalents. EUC-TW has been discussed in
http://bugs.python.org/issue2066 and rejected (see
http://bugs.python.org/issue2066#msg113731).

If you use any of these encodings, you *will* get into the recursion
trouble described eariler, just as before the path you'd get into it
with CP1252 as your encoding.

What shall we do about those? Ignore them? Document that if you're sing
one of these encodings then PL/Python with Python 2 will be crippled and
with Python 3 just won't work?

Cheers,
Jan