Re: Almost bug in COPY FROM processing of GB18030 encoded input

On 24/01/2019 23:27, Robert Haas wrote:
> On Wed, Jan 23, 2019 at 6:23 AM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>> I happened to notice that when CopyReadLineText() calls mblen(), it
>> passes only the first byte of the multi-byte characters. However,
>> pg_gb18030_mblen() looks at the first and the second byte.
>> CopyReadLineText() always passes \0 as the second byte, so
>> pg_gb18030_mblen() will incorrectly report the length of 4-byte encoded
>> characters as 2.
>>
>> It works out fine, though, because the second half of the 4-byte encoded
>> character always looks like another 2-byte encoded character, in
>> GB18030. CopyReadLineText() is looking for delimiter and escape
>> characters and newlines, and only single-byte characters are supported
>> for those, so treating a 4-byte character as two 2-byte characters is
>> harmless.
> 
> Yikes.

Committed the comment changes, so it's less of a gotcha now.

- Heikki