Guard against overflow in interval_mul() and interval_div().
Commits 146604ec43 and a898b409f6 added overflow checks to
interval_mul(), but not to interval_div(), which contains almost
identical code, and so is susceptible to the same kinds of
overflows. In addition, those checks did not catch all possible
overflow conditions.
Add additional checks to the "cascade down" code in interval_mul(),
and copy all the overflow checks over to the corresponding code in
interval_div(), so that they both generate "interval out of range"
errors, rather than returning bogus results.
Given that these errors are relatively easy to hit, back-patch to all
supported branches.
Per bug #18200 from Alexander Lakhin, and subsequent investigation.
Discussion: https://postgr.es/m/18200-5ea288c7b2d504b1%40postgresql.org
Branch
------
REL_15_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/2851aa7d1fc3bd3dfac00ff2250a7e029ed6499f
Modified Files
--------------
src/backend/utils/adt/timestamp.c | 69 +++++++++++++++++++++++-----------
src/test/regress/expected/interval.out | 13 +++++++
src/test/regress/sql/interval.sql | 8 ++++
3 files changed, 69 insertions(+), 21 deletions(-)