--source include/have_innodb.inc

--echo #
--echo # MDEV-26294 Duplicate entries in unique index not detected when
--echo #	changing collation with INPLACE algorithm
--echo #

# Detect the duplicate entry after collation change of column

SET NAMES utf8;
CREATE TABLE t1 (
  id INT PRIMARY KEY,
  msg VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_swedish_ci UNIQUE
) ENGINE=INNODB;
INSERT INTO t1 VALUES (1, 'aaa');
INSERT INTO t1 VALUES (2, 'ååå');
--error ER_ALTER_OPERATION_NOT_SUPPORTED_REASON
ALTER TABLE t1
MODIFY msg VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_unicode_ci,
ALGORITHM=NOCOPY;
ALTER TABLE t1 DROP INDEX msg,
MODIFY msg VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_unicode_ci,
ALGORITHM=NOCOPY;
DROP TABLE t1;