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Date: Tue, 14 Apr 2026 11:50:50 +0300
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Subject: Re: BUG #19354: JOHAB rejects valid byte sequences
To: Thomas Munro <thomas.munro@gmail.com>, Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Jeroen Vermeulen <jtvjtv@gmail.com>,
 VASUKI M <vasukianand0119@gmail.com>, pgsql-bugs@lists.postgresql.org
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From: Heikki Linnakangas <hlinnaka@iki.fi>
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On 14/04/2026 09:30, Thomas Munro wrote:
> On Wed, Dec 17, 2025 at 7:43 AM Robert Haas <robertmhaas@gmail.com> wrote:
>> I think there is a good chance that the right going-forward fix is to
>> deprecate the encoding, because according to
>> https://www.unicode.org/Public/MAPPINGS/EASTASIA/ReadMe.txt this and
>> everything else that's now under
>> https://www.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/ were
>> deprecated in 2001. By the time v19 is released, the deprecation will
>> be a quarter-century old, and the fact that it doesn't work is good
>> evidence that few people will miss it, though perhaps the original
>> poster will want to put forward an argument for why we should still
>> care about this.
> 
> Right, that stuff was withdrawn, along with the BIG5 and JIS X 0212
> mappings (here's some interesting discussion about their normative
> status[1]).  From what I can figure out, JOHAB was an MS-DOS codepage
> (1361), obsoleted by UHC (949) some time around MS-DOS 6.22 or MS-DOS
> 7 and Windows 95.
> 
> So +1 from me, set the phasers to git rm.

+1

> Based on the comments for enum pg_enc, we don't need to worry about
> numerical stability of client-only encodings, so I just deleted it
> (unlike PG_MULE_INTERNAL which became PG_UNUSED_1).
Ok. I hope there are no 8.2-era client programs out there that are still 
abusing pg_wchar.h. I think we're good, but we've never really exercised 
the strategy that was laid out in commit 8468146b03c8.

> Wait until 20, or just do it now?
Let's just do it now.
- Heikki