Re: [PATCHES] to_char and Roman Numeral (RN) bug

I have checked this in CVS and it is working fine. Karel, have you
fixed this? I can't find a place where I have applied a fix for this.

> Good day,
>
> Sorry to post to this list about a patch, but I seem to be having some
> difficult getting on the pgsql-patches list; keep getting an "illegal
> command" when I send it "subscribe", for some reason. At any rate:
>
> In documenting the to_char() function for transformation of numbers to
> text, I noticed that the "RN" template character sequence was displaying
> some unusual behavior; specifically, unless in fill mode (with the "FM"
> sequence), it would either return the result of the last query executed
> derived from a to_char() result, or what appears to be a garbage pointer
> if there was no such last query.
>
> Example output from PostgreSQL 7.1.3:
> -------------------------------------------------------
> lx=# SELECT to_char(485, 'RN');
> to_char
> -----------------
> UERY :command 1
> (1 row)
>
> lx=# SELECT to_char(485, 'FMRN');
> to_char
> ---------
> CDLXXXV
> (1 row)
>
> lx=# SELECT to_char(485, 'RN');
> to_char
> ---------
> CDLXXXV
> (1 row)
>
> lx=# SELECT to_char(1000, 'RN');
> to_char
> ---------
> CDLXXXV
> (1 row)
>
> lx=# SELECT 1, 2, to_char(900, '999');
> ?column? | ?column? | to_char
> ----------+----------+---------
> 1 | 2 | 900
> (1 row)
>
> lx=# SELECT to_char(485, 'RN');
> to_char
> ---------
> 900
> (1 row)
> -------------------------------------------------------
>
> Upon looking into src/backend/utils/adt/formatting.c, I noticed that for
> RN transforms:
>
> strcpy(Np->inout_p, Np->number_p);
>
> was only being called within the IS_FILLMODE if block. Moving it out, and
> above that check seems to correct this behavior, and I've attached Patches
> for both today's pgsql CVS snapshot and postgresql-7.1.3. Both compile,
> but I've only tested the latter since my data path is not setup for
> pre-7.2, and it seems like a fairly small change.
>
> I consider myself a competent programmer, but never having hacked on
> Postgres, I'm not 100% sure that this modification is totally correct
> (e.g., if there are any strange side-effects from doing this?), since I'm
> not even sure what the Np pointers are achieving in this instance. ;) I'm
> guessing its copying the actual output result into the output value's
> char* pointer, as that would explain the garbage pointer if it was never
> copied.
>
> Any explanation would be greatly appreciated, as I'd like to document this
> apparent bug correctly.
>
>
> Regards,
> Jw.
> --
> jlx(at)commandprompt(dot)com - John Worsley @ Command Prompt, Inc.
> by way of pgsql-hackers(at)commandprompt(dot)com

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