Re: BUG #19354: JOHAB rejects valid byte sequences

Jeroen Vermeulen <jtvjtv@gmail.com> writes:
> This bit worries me: "TlOther, vendor-defined, Johab variants also exist" —
> such as an EBCDIC-based one and a stateful one!

Yeah.  So what we have here is:

1. Our JOHAB implementation has apparently been wrong since day one.

2. Wrongness may be in the eye of the beholder, since there are
multiple versions of JOHAB.

3. Your complaint is the first, AFAIR.

4. That wikipedia page says "Following the introduction of Unified
Hangul Code by Microsoft in Windows 95, and Hangul Word Processor
abandoning Johab in favour of Unicode in 2000, Johab ceased to be
commonly used."

Given these things, I wonder if we shouldn't desupport JOHAB
rather than attempt to fix it.  Fixing would likely be a significant
amount of work: if we don't even have the character lengths right,
how likely is it that our conversions to other character sets are
correct?  I also worry that if different PG versions have different
ideas of the mapping, there could be room for dump/reload problems,
and maybe even security problems related to the backslash issue.

            regards, tom lane