Thread: pgsql: Avoid formally-undefined use of memcpy() inhstoreUniquePairs().

Avoid formally-undefined use of memcpy() in hstoreUniquePairs().

hstoreUniquePairs() often called memcpy with equal source and destination
pointers.  Although this is almost surely harmless in practice, it's
undefined according to the letter of the C standard.  Some versions of
valgrind will complain about it, and some versions of libc as well
(cf. commit ad520ec4a).  Tweak the code to avoid doing that.

Noted by Tomas Vondra.  Back-patch to all supported versions because
of the hazard of libc assertions.

Discussion: https://postgr.es/m/bf84d940-90d4-de91-19dd-612e011007f4@fuzzy.cz

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/ddba320059fcce0126ea43f0c0404d3ed1ce47aa

Modified Files
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contrib/hstore/hstore_io.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)