Fix text substring search for non-deterministic collations. Due to an off-by-one error, the code failed to find matches at the end of the haystack. Fix by rewriting the loop.
While at it, fix a comment that claimed that the function could find a zero-length match. Such a match could send a caller into an endless loop. However, zero-length matches only make sense with an empty search string, and that case is explicitly excluded by all callers. To make sure it stays that way, add an Assert and a comment. Bug: #19341 Reported-by: Adam Warland <[email protected]> Author: Laurenz Albe <[email protected]> Reviewed-by: Heikki Linnakangas <[email protected]> Reviewed-by: Tom Lane <[email protected]> Discussion: https://postgr.es/m/[email protected] Backpatch-through: 18 Branch ------ REL_18_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/18b349315ae7e00261732f514d6c91d713bb77d0 Modified Files -------------- src/backend/utils/adt/varlena.c | 25 ++++++++++++++++++------- src/test/regress/expected/collate.icu.utf8.out | 7 +++++++ src/test/regress/sql/collate.icu.utf8.sql | 3 +++ 3 files changed, 28 insertions(+), 7 deletions(-)
