Re: length coerce for bpchar is broken since 7.0

Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp> writes:
>> bpcharin() will most definitely NOT fix the problem, because it often
>> will not know the target column's typmod, if indeed there is an
>> identifiable target column at all.

> Can you give me any example for this case?

UPDATE foo SET bpcharcol = 'a'::char || 'b'::char;

UPDATE foo SET bpcharcol = upper('abc');

In the first case bpcharin() will be invoked, but not in the context
of direct assignment to a table column, so it won't receive a valid
typmod. In the second case bpcharin() will never be invoked at all,
because upper takes and returns text --- so 'abc' is not a bpchar
constant but a text constant. You have to be sure that the parser
handles type length coercion correctly, and I think the cleanest way to
do that is to fix exprTypmod so that it knows how typmod is defined in
the MULTIBYTE case.

regards, tom lane