From bb200599fff17602465668aee0ad4a614ee5528e Mon Sep 17 00:00:00 2001
From: Alexander Barkov <bar@mariadb.com>
Date: Wed, 3 Nov 2021 15:29:35 +0400
Subject: [PATCH] MDEV-24584 Selecting INT column with COLLATE
 utf8mb4_general_ci throws an error

---
 mysql-test/main/ctype_ucs.result     | 19 +++++++++++++++++++
 mysql-test/main/ctype_ucs.test       | 13 +++++++++++++
 mysql-test/main/ctype_utf8mb4.result | 18 ++++++++++++++++++
 mysql-test/main/ctype_utf8mb4.test   | 19 +++++++++++++++++++
 sql/item_strfunc.cc                  |  6 ++++--
 5 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/mysql-test/main/ctype_ucs.result b/mysql-test/main/ctype_ucs.result
index dc3ed0cf7a9..6c14ca3ab66 100644
--- a/mysql-test/main/ctype_ucs.result
+++ b/mysql-test/main/ctype_ucs.result
@@ -6473,5 +6473,24 @@ CAST(_ucs2 0x0061E0030062 AS INT)
 Warnings:
 Warning	1292	Truncated incorrect INTEGER value: 'ab'
 #
+# MDEV-24584 Selecting INT column with COLLATE utf8mb4_general_ci throws an error
+#
+SET NAMES utf8, collation_connection=ucs2_general_ci;
+SELECT 1 COLLATE ucs2_general_ci;
+1 COLLATE ucs2_general_ci
+1
+SELECT 1 COLLATE ucs2_bin;
+1 COLLATE ucs2_bin
+1
+SELECT HEX(1 COLLATE ucs2_general_ci);
+HEX(1 COLLATE ucs2_general_ci)
+0031
+SELECT HEX(1 COLLATE ucs2_bin);
+HEX(1 COLLATE ucs2_bin)
+0031
+SELECT 1 COLLATE latin1_swedish_ci;
+ERROR 42000: COLLATION 'latin1_swedish_ci' is not valid for CHARACTER SET 'ucs2'
+SET NAMES utf8;
+#
 # End of 10.5 tests
 #
diff --git a/mysql-test/main/ctype_ucs.test b/mysql-test/main/ctype_ucs.test
index cdc86fa3283..8f566fe831e 100644
--- a/mysql-test/main/ctype_ucs.test
+++ b/mysql-test/main/ctype_ucs.test
@@ -1146,6 +1146,19 @@ SELECT CAST(_ucs2 0x0061DFFF0062 AS INT);
 SELECT CAST(_ucs2 0x0061D7000062 AS INT);
 SELECT CAST(_ucs2 0x0061E0030062 AS INT);
 
+--echo #
+--echo # MDEV-24584 Selecting INT column with COLLATE utf8mb4_general_ci throws an error
+--echo #
+
+SET NAMES utf8, collation_connection=ucs2_general_ci;
+SELECT 1 COLLATE ucs2_general_ci;
+SELECT 1 COLLATE ucs2_bin;
+SELECT HEX(1 COLLATE ucs2_general_ci);
+SELECT HEX(1 COLLATE ucs2_bin);
+--error ER_COLLATION_CHARSET_MISMATCH
+SELECT 1 COLLATE latin1_swedish_ci;
+SET NAMES utf8;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #
diff --git a/mysql-test/main/ctype_utf8mb4.result b/mysql-test/main/ctype_utf8mb4.result
index 5d039195f33..5c04eafdf70 100644
--- a/mysql-test/main/ctype_utf8mb4.result
+++ b/mysql-test/main/ctype_utf8mb4.result
@@ -4149,3 +4149,21 @@ c
 #
 # End of 10.2 tests
 #
+#
+# Start of 10.5 tests
+#
+#
+# MDEV-24584 Selecting INT column with COLLATE utf8mb4_general_ci throws an error
+#
+SET NAMES utf8mb4;
+SELECT 1 COLLATE utf8mb4_general_ci;
+1 COLLATE utf8mb4_general_ci
+1
+SELECT 1 COLLATE utf8mb4_bin;
+1 COLLATE utf8mb4_bin
+1
+SELECT 1 COLLATE latin1_swedish_ci;
+ERROR 42000: COLLATION 'latin1_swedish_ci' is not valid for CHARACTER SET 'utf8mb4'
+#
+# End of 10.5 tests
+#
diff --git a/mysql-test/main/ctype_utf8mb4.test b/mysql-test/main/ctype_utf8mb4.test
index 8fbbee872ce..5640bc45ed1 100644
--- a/mysql-test/main/ctype_utf8mb4.test
+++ b/mysql-test/main/ctype_utf8mb4.test
@@ -2043,3 +2043,22 @@ EXECUTE IMMEDIATE 'SELECT ''😎'' AS c';
 --echo #
 --echo # End of 10.2 tests
 --echo #
+
+
+--echo #
+--echo # Start of 10.5 tests
+--echo #
+
+--echo #
+--echo # MDEV-24584 Selecting INT column with COLLATE utf8mb4_general_ci throws an error
+--echo #
+
+SET NAMES utf8mb4;
+SELECT 1 COLLATE utf8mb4_general_ci;
+SELECT 1 COLLATE utf8mb4_bin;
+--error ER_COLLATION_CHARSET_MISMATCH
+SELECT 1 COLLATE latin1_swedish_ci;
+
+--echo #
+--echo # End of 10.5 tests
+--echo #
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index 2967a0b42aa..e7abb51893c 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -3552,10 +3552,12 @@ String *Item_func_set_collation::val_str(String *str)
 
 bool Item_func_set_collation::fix_length_and_dec()
 {
-  if (!my_charset_same(args[0]->collation.collation, m_set_collation))
+  if (agg_arg_charsets_for_string_result(collation, args, 1))
+    return true;
+  if (!my_charset_same(collation.collation, m_set_collation))
   {
     my_error(ER_COLLATION_CHARSET_MISMATCH, MYF(0),
-             m_set_collation->name, args[0]->collation.collation->csname);
+             m_set_collation->name, collation.collation->csname);
     return TRUE;
   }
   collation.set(m_set_collation, DERIVATION_EXPLICIT,