From e24685619daed171fe28d0857abfb92deac6e5a8 Mon Sep 17 00:00:00 2001 From: Jeff Davis Date: Wed, 21 Oct 2026 05:46:37 -0700 Subject: [PATCH] Fix ILIKE patterns with non-ASCII bytes in single-byte encodings. Commit 1e493158d3d changed the MATCH_LOWER implementation of GETCHAR() from SB_lower_char() to use pg_ascii_tolower(). The latter returns an unsigned char; but the local variable in C_IMatchText was a char. For single-byte encodings and the C locale, that could lead to a broken signed/unsigned comparison. For example, the pattern U&'%\00C6' would never match. Fix by casting the result of pg_ascii_tolower() explicitly to char. Reported-by: Greg Burd Reviewed-by: Greg Burd Discussion: https://postgr.es/m/_GW2V-rd0QW4BTguAJriA9XVmjOn2mR3-YeAZr9ZU6EtlLvYPEm_r_fV5wGKzSNMzboj_nqn3fk72AYAvOKzEnPlCCHteaYrgESrIhPg6l8=@burd.me Backpatch-through: 19 --- src/backend/utils/adt/like_match.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/backend/utils/adt/like_match.c b/src/backend/utils/adt/like_match.c index defcaa96fb5..0249eb49a7d 100644 --- a/src/backend/utils/adt/like_match.c +++ b/src/backend/utils/adt/like_match.c @@ -75,7 +75,8 @@ * locales must casefold the inputs before matching. */ #ifdef MATCH_LOWER -#define GETCHAR(t) pg_ascii_tolower(t) +/* cast to char to match data types in caller */ +#define GETCHAR(t) ((char) pg_ascii_tolower(t)) #else #define GETCHAR(t) (t) #endif