Richard Guo 1132af22cf Fix HAVING-to-WHERE pushdown for simple-CASE form ... Commit f76686ce7 added a walker that detects when a HAVING clause uses a collation that conflicts with the GROUP BY's nondeterministic collation, keeping such clauses in HAVING. The walker uses exprInputCollation() to identify each ancestor's comparison collation, but missed the simple-CASE case: parse analysis builds each WHEN as OpExpr(CaseTestExpr op val), where CaseTestExpr is a placeholder for the arg, while the actual arg expression sits at cexpr->arg, outside the OpExpr that carries the comparison's inputcollid. A GROUP Var at cexpr->arg was therefore visited with the WHEN's inputcollid absent from the ancestor stack, the conflict went undetected, and the clause was wrongly pushed to WHERE. Fix by handling simple CASE explicitly: before walking cexpr->arg, push every WHEN's inputcollid onto the ancestor stack so a GROUP Var at the arg is checked against the same collations the WHEN comparisons would apply. Then walk the WHEN bodies and defresult under the unchanged stack, where their own collation contexts are picked up by the default path. Back-patch to v18 only; this fix extends the walker added by commit f76686ce7 and inherits its dependency on the v18 RTE_GROUP mechanism. Author: SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com> Reviewed-by: Richard Guo <guofenglinux@gmail.com> Discussion: https://postgr.es/m/CAHg+QDcqPdd=2V0PQ_oNYj50OUeqSqznqFaYtP3RdokLBDXBqw@mail.gmail.com Backpatch-through: 18		2026-05-08 10:59:13 +09:00
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backend	Fix HAVING-to-WHERE pushdown for simple-CASE form	2026-05-08 10:59:13 +09:00
bin	pg_test_timing: fix unit in backward-clock warning	2026-04-24 09:03:30 +09:00
common	Fix callers of unicode_strtitle() using srclen == -1.	2026-04-20 14:45:44 -07:00
fe_utils	Harden astreamer tar parsing logic against archives it can't handle.	2026-04-02 12:20:26 -04:00
include	Add missing guard for __builtin_constant_p	2026-05-05 18:51:27 +07:00
interfaces	Add missing connection validation in ECPG	2026-05-01 15:15:15 -04:00
makefiles	pgxs.mk: remove unreachable rule for deleting regress.def.	2025-06-20 12:12:29 -04:00
pl	Make plpgsql_trap test more robust and less resource-intensive.	2026-04-21 10:54:39 -04:00
port	Suppress "has no symbols" linker warnings on macOS.	2026-04-29 12:25:09 -05:00
template	thread-safety: gmtime_r(), localtime_r()	2024-08-23 07:43:04 +02:00
test	Fix HAVING-to-WHERE pushdown for simple-CASE form	2026-05-08 10:59:13 +09:00
timezone	Update time zone data files to tzdata release 2026b.	2026-04-24 12:28:35 -04:00
tools	Consider collation when proving subquery uniqueness	2026-05-05 10:27:06 +09:00
tutorial	Doc: simplify the tutorial's window-function examples.	2025-01-21 14:43:21 -05:00
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meson.build	Update copyright for 2025	2025-01-01 11:21:55 -05:00
nls-global.mk	Fix update-po for the PGXS case	2025-10-16 20:21:05 +02:00