Float value 'Infinity' is cast to numeric 1 on Windows

Hello,

Does it make sense to put a check of "isinf(val)" and ereport prior to
the snprintf()?
It is a lightweight check more than set_var_from_str().

Thanks,

2017-09-27 19:41 GMT+09:00 Taiki Kondo <tai-kondo@yk.jp.nec.com>:

Hi all,

I build PostgreSQL 9.6.5 by Visual Studio 2013 on Windows, I found weird behavior on it.

I execute following SQL, occurring ERROR is expected, but I got mysterious value 1.

postgres=# select (float8 'inf')::numeric;
numeric
---------
1
(1 row)

On Windows, at least Visual Studio, the string of float/double value meaning
infinity is "1.#INF" not "inf". So, set_var_from_str() called from float8_numeric()
in utils/adt/numeric.c will return numeric value 1, and no one checks this situation.

This situation is also occurring by cast from float4.

I wrote a patch to add check this situation.
Please find attached.

Sincerely,

--
Taiki Kondo
NEC Solution Innovators, Ltd.

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HeteroDB, Inc / The PG-Strom Project
KaiGai Kohei <kaigai@heterodb.com>

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Kohei KaiGai <kaigai@heterodb.com> writes:

Does it make sense to put a check of "isinf(val)" and ereport prior to
the snprintf()?

Yeah, that was my reaction too. Obviously this wasn't thought about
in the original coding ...

regards, tom lane

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