From 42738f5f4d5c1cef5a9166ff496827b2abd6344c Mon Sep 17 00:00:00 2001
From: Alexander Barkov <bar@mariadb.com>
Date: Mon, 17 Jul 2023 06:52:18 +0400
Subject: [PATCH] MDEV-30681 SIGFPE / UBSAN runtime error: division by zero in
 String::needs_conversion on ALTER

The problem was earlier fixed by MDEV-30805. Adding an MTR test only.
---
 mysql-test/main/partition_charset.result | 12 ++++++++++++
 mysql-test/main/partition_charset.test   | 11 +++++++++++
 2 files changed, 23 insertions(+)

diff --git a/mysql-test/main/partition_charset.result b/mysql-test/main/partition_charset.result
index a0019dd8fc3..d9e496c475e 100644
--- a/mysql-test/main/partition_charset.result
+++ b/mysql-test/main/partition_charset.result
@@ -39,5 +39,17 @@ t1	CREATE TABLE `t1` (
 (PARTITION `p0` VALUES LESS THAN ('a') ENGINE = MyISAM)
 DROP TABLE t1;
 #
+# MDEV-30681 SIGFPE / UBSAN runtime error: division by zero in String::needs_conversion on ALTER
+#
+CREATE TABLE t1 (a BINARY (10)) PARTITION BY LIST COLUMNS (a) (PARTITION p VALUES IN (0xFF));
+SELECT COLUMN_TYPE, COLLATION_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='t1';
+COLUMN_TYPE	COLLATION_NAME
+binary(10)	NULL
+ALTER TABLE t1 CHANGE COLUMN a a CHAR(10) BINARY;
+SELECT COLUMN_TYPE, COLLATION_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='t1';
+COLUMN_TYPE	COLLATION_NAME
+char(10)	latin1_bin
+DROP TABLE t1;
+#
 # End of 10.9 tests
 #
diff --git a/mysql-test/main/partition_charset.test b/mysql-test/main/partition_charset.test
index b8a17ce4fca..87aa42b4f7c 100644
--- a/mysql-test/main/partition_charset.test
+++ b/mysql-test/main/partition_charset.test
@@ -43,6 +43,17 @@ ALTER TABLE t1 CHANGE COLUMN a a CHAR BINARY;
 SHOW CREATE TABLE t1;
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-30681 SIGFPE / UBSAN runtime error: division by zero in String::needs_conversion on ALTER
+--echo #
+
+CREATE TABLE t1 (a BINARY (10)) PARTITION BY LIST COLUMNS (a) (PARTITION p VALUES IN (0xFF));
+SELECT COLUMN_TYPE, COLLATION_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='t1';
+ALTER TABLE t1 CHANGE COLUMN a a CHAR(10) BINARY;
+SELECT COLUMN_TYPE, COLLATION_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='t1';
+DROP TABLE t1;
+
+
 --echo #
 --echo # End of 10.9 tests
 --echo #