From 80067a69feaeb5df30abb1bfaf7d4e713ccbf027 Mon Sep 17 00:00:00 2001
From: Sergei Petrunia <sergey@mariadb.com>
Date: Mon, 10 Feb 2025 22:22:39 +0200
Subject: [PATCH] MDEV-36057: Assertion failure on 2nd execution of
 parameterized PS

Followup to fix for MDEV-35318: In Prepared_statement::execute_loop(),
if we enter this function with lex->needs_reprepare=true, we need to
re-prepare the statement.
We also need to call set_parameters() to get PS parameter values. We
failed to do this and that's the bug.

Note that we need to also handle the other reprepare scenario: when
we get into Prepared_statement::execute_loop(), call set_parameters()
and then hit a "DDL was changed" error with reprepare_observer,
we should NOT call set_parameters() again.
The parameters have already been transferred to the reprepared statement
in Prepared_statement::reprepare()|swap_parameter_array().
---
 mysql-test/main/create.result | 12 ++++++++++++
 mysql-test/main/create.test   | 14 ++++++++++++++
 sql/sql_prepare.cc            |  7 +++++--
 3 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/mysql-test/main/create.result b/mysql-test/main/create.result
index 55521c18b76..46d8d68121c 100644
--- a/mysql-test/main/create.result
+++ b/mysql-test/main/create.result
@@ -2116,4 +2116,16 @@ Warnings:
 Note	1051	Unknown table 'test.tmp'
 DROP PROCEDURE sp1;
 DROP TABLE t;
+#
+# MDEV-36057: Assertion failure or unexpected outcome upon 2nd execution
+#             of parameterized PS (continues the above)
+#
+CREATE TABLE t (a INT);
+INSERT INTO t VALUES (1),(2);
+PREPARE stmt FROM 'UPDATE t SET a = 3 WHERE a IN (SELECT "" UNION SELECT ?)';
+EXECUTE stmt USING 4;
+ERROR 22007: Truncated incorrect DECIMAL value: ''
+EXECUTE stmt USING 4;
+ERROR 22007: Truncated incorrect DECIMAL value: ''
+DROP TABLE t;
 # End of 11.7 Test
diff --git a/mysql-test/main/create.test b/mysql-test/main/create.test
index 1213c8be6e0..bb0c6347f2e 100644
--- a/mysql-test/main/create.test
+++ b/mysql-test/main/create.test
@@ -1987,4 +1987,18 @@ call sp1();
 DROP PROCEDURE sp1;
 DROP TABLE t;
 
+--echo #
+--echo # MDEV-36057: Assertion failure or unexpected outcome upon 2nd execution
+--echo #             of parameterized PS (continues the above)
+--echo #
+CREATE TABLE t (a INT);
+INSERT INTO t VALUES (1),(2);
+
+PREPARE stmt FROM 'UPDATE t SET a = 3 WHERE a IN (SELECT "" UNION SELECT ?)';
+--error ER_TRUNCATED_WRONG_VALUE
+EXECUTE stmt USING 4;
+--error ER_TRUNCATED_WRONG_VALUE
+EXECUTE stmt USING 4;
+DROP TABLE t;
+
 --echo # End of 11.7 Test
diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 1fa872b8d55..0488b6de558 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -4390,6 +4390,7 @@ Prepared_statement::execute_loop(String *expanded_query,
   Reprepare_observer reprepare_observer;
   bool error;
   iterations= FALSE;
+  bool params_are_set= false;
 
   /*
     - In mysql_sql_stmt_execute() we hide all "external" Items
@@ -4415,8 +4416,10 @@ Prepared_statement::execute_loop(String *expanded_query,
     return TRUE;
   }
 
-  if (set_parameters(expanded_query, packet, packet_end))
+reexecute:
+  if (!params_are_set && set_parameters(expanded_query, packet, packet_end))
     return TRUE;
+  params_are_set= true;
 #ifdef WITH_WSREP
   if (thd->wsrep_delayed_BF_abort)
   {
@@ -4424,7 +4427,7 @@ Prepared_statement::execute_loop(String *expanded_query,
     return TRUE;
   }
 #endif /* WITH_WSREP */
-reexecute:
+
   // Make sure that reprepare() did not create any new Items.
   DBUG_ASSERT(thd->free_list == NULL);