Improve to_date/to_number/to_timestamp behavior with multibyte characters.
The documentation says that these functions skip one input character
per literal (non-pattern) format character. Actually, though, they
skipped one input *byte* per literal *byte*, which could be hugely
confusing if either data or format contained multibyte characters.
To fix, adjust the FormatNode representation and parse_format() so
that multibyte format characters are stored as one FormatNode not
several, and adjust the data-skipping bits to advance by pg_mblen()
not necessarily one byte. There's no user-visible behavior change
on the to_char() side, although the internal representation changes.
Commit e87d4965b had already fixed most places where we skip characters
on the basis of non-literal format patterns to advance by characters
not bytes, but this gets one more place, the SKIP_THth macro. I think
everything in formatting.c gets that right now.
It'd be nice to have some regression test cases covering this behavior;
but of course there's no way to do so in an encoding-agnostic way, and
many of the interesting aspects would also require unportable locale
selections. So I've not bothered here.
Discussion: https://postgr.es/m/28186.1510957703@sss.pgh.pa.us
Branch
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master
Details
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https://git.postgresql.org/pg/commitdiff/976a1a48fc35cde3c750982be64f872c4de4d343
Modified Files
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src/backend/utils/adt/formatting.c | 68 +++++++++++++++++++++++---------------
1 file changed, 41 insertions(+), 27 deletions(-)
