From df39412790cbe87b704890f2ac25dbcbb365932c Mon Sep 17 00:00:00 2001
From: Alexander Barkov <bar@mariadb.com>
Date: Fri, 1 Oct 2021 17:12:00 +0400
Subject: MDEV-26743 InnoDB: CHAR+nopad does not work well

The patch for "MDEV-25440: Indexed CHAR ... broken with NO_PAD collations"
also fixed MDEV-26743. Adding tests only.
---
 mysql-test/suite/innodb/r/no_pad.result | 46 +++++++++++++++++++++++++++++++++
 mysql-test/suite/innodb/t/no_pad.test   | 46 +++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+)

diff --git a/mysql-test/suite/innodb/r/no_pad.result b/mysql-test/suite/innodb/r/no_pad.result
index 0c039c30a5e..2af5eb0207f 100644
--- a/mysql-test/suite/innodb/r/no_pad.result
+++ b/mysql-test/suite/innodb/r/no_pad.result
@@ -5,3 +5,49 @@ ALTER TABLE t1 ROW_FORMAT=DYNAMIC;
 INSERT INTO t1 VALUES ('',2);
 ALTER TABLE t1 ROW_FORMAT=REDUNDANT;
 DROP TABLE t1;
+#
+# MDEV-26743 InnoDB: CHAR+nopad does not work well
+#
+#
+# Basic Latin letter vs equal accented letter
+#
+SET NAMES utf8mb3;
+CREATE TABLE t1 (a CHAR(2), PRIMARY KEY(a)) COLLATE utf8_unicode_nopad_ci ENGINE=InnoDB ROW_FORMAT=COMPACT;
+INSERT INTO t1 VALUES ('a'),('ä');
+ERROR 23000: Duplicate entry 'ä' for key 'PRIMARY'
+DROP TABLE t1;
+#
+# Two letters vs equal (but space padded) expansion
+#
+CREATE TABLE t1 (a CHAR(2), PRIMARY KEY(a)) COLLATE utf8_unicode_nopad_ci ENGINE=InnoDB ROW_FORMAT=COMPACT;
+INSERT INTO t1 VALUES ('ss'),('ß');
+SET sql_mode=PAD_CHAR_TO_FULL_LENGTH;
+SELECT HEX(a) FROM t1;
+HEX(a)
+7373
+C39F20
+SET sql_mode=DEFAULT;
+DROP TABLE t1;
+#
+# Basic Latin letter (but followed by an ignorable character) vs equal accented letter
+#
+SET NAMES utf8mb3;
+CREATE TABLE t1 (a CHAR(3), PRIMARY KEY(a)) CHARACTER SET utf8mb3 COLLATE utf8mb3_unicode_nopad_ci ENGINE=InnoDB ROW_FORMAT=COMPACT;
+INSERT INTO t1 VALUES (CONCAT('a',_utf8mb3 0x01)),('ä');
+SET sql_mode=PAD_CHAR_TO_FULL_LENGTH;
+SELECT HEX(a) FROM t1 ORDER BY HEX(a);
+HEX(a)
+610120
+C3A42020
+SET sql_mode=DEFAULT;
+DROP TABLE t1;
+SET NAMES utf8mb3;
+CREATE TABLE t1 (a CHAR(2), PRIMARY KEY(a)) COLLATE utf8_unicode_nopad_ci ENGINE=InnoDB ROW_FORMAT=COMPACT;
+INSERT INTO t1 VALUES (CONCAT('a',_utf8mb3 0x01)),('ä');
+SET sql_mode=PAD_CHAR_TO_FULL_LENGTH;
+SELECT HEX(a) FROM t1 ORDER BY HEX(a);
+HEX(a)
+6101
+C3A420
+SET sql_mode=DEFAULT;
+DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/t/no_pad.test b/mysql-test/suite/innodb/t/no_pad.test
index 1be1972c9ca..15ab71b6c7f 100644
--- a/mysql-test/suite/innodb/t/no_pad.test
+++ b/mysql-test/suite/innodb/t/no_pad.test
@@ -8,3 +8,49 @@ ALTER TABLE t1 ROW_FORMAT=DYNAMIC;
 INSERT INTO t1 VALUES ('',2);
 ALTER TABLE t1 ROW_FORMAT=REDUNDANT;
 DROP TABLE t1;
+
+
+--echo #
+--echo # MDEV-26743 InnoDB: CHAR+nopad does not work well
+--echo #
+
+--echo #
+--echo # Basic Latin letter vs equal accented letter
+--echo #
+
+SET NAMES utf8mb3;
+CREATE TABLE t1 (a CHAR(2), PRIMARY KEY(a)) COLLATE utf8_unicode_nopad_ci ENGINE=InnoDB ROW_FORMAT=COMPACT;
+--error ER_DUP_ENTRY
+INSERT INTO t1 VALUES ('a'),('ä');
+DROP TABLE t1;
+
+--echo #
+--echo # Two letters vs equal (but space padded) expansion
+--echo #
+
+CREATE TABLE t1 (a CHAR(2), PRIMARY KEY(a)) COLLATE utf8_unicode_nopad_ci ENGINE=InnoDB ROW_FORMAT=COMPACT;
+INSERT INTO t1 VALUES ('ss'),('ß');
+SET sql_mode=PAD_CHAR_TO_FULL_LENGTH;
+SELECT HEX(a) FROM t1;
+SET sql_mode=DEFAULT;
+DROP TABLE t1;
+
+--echo #
+--echo # Basic Latin letter (but followed by an ignorable character) vs equal accented letter
+--echo #
+
+SET NAMES utf8mb3;
+CREATE TABLE t1 (a CHAR(3), PRIMARY KEY(a)) CHARACTER SET utf8mb3 COLLATE utf8mb3_unicode_nopad_ci ENGINE=InnoDB ROW_FORMAT=COMPACT;
+INSERT INTO t1 VALUES (CONCAT('a',_utf8mb3 0x01)),('ä');
+SET sql_mode=PAD_CHAR_TO_FULL_LENGTH;
+SELECT HEX(a) FROM t1 ORDER BY HEX(a);
+SET sql_mode=DEFAULT;
+DROP TABLE t1;
+
+SET NAMES utf8mb3;
+CREATE TABLE t1 (a CHAR(2), PRIMARY KEY(a)) COLLATE utf8_unicode_nopad_ci ENGINE=InnoDB ROW_FORMAT=COMPACT;
+INSERT INTO t1 VALUES (CONCAT('a',_utf8mb3 0x01)),('ä');
+SET sql_mode=PAD_CHAR_TO_FULL_LENGTH;
+SELECT HEX(a) FROM t1 ORDER BY HEX(a);
+SET sql_mode=DEFAULT;
+DROP TABLE t1;
-- 
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