From fef3e4ed6d60f0a4fd14a08e8902d30db0215f1d Mon Sep 17 00:00:00 2001
From: Georg Richter <georg@mariadb.com>
Date: Sat, 23 Mar 2024 12:53:24 +0100
Subject: [PATCH] CONC-683: Check pending results when closing statement.

Similiar to fix for CONC-667 we need to check if other
statements have a pending result set before we can close
a statement handle.
---
 libmariadb/mariadb_stmt.c     | 30 +++++++++++++++++++++++-------
 unittest/libmariadb/ps_bugs.c | 30 ++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 7 deletions(-)

diff --git a/libmariadb/mariadb_stmt.c b/libmariadb/mariadb_stmt.c
index 92f1869c..594d149f 100644
--- a/libmariadb/mariadb_stmt.c
+++ b/libmariadb/mariadb_stmt.c
@@ -123,6 +123,20 @@ void stmt_set_error(MYSQL_STMT *stmt,
   return;
 }
 
+/* checks if there are any other statements which have a
+   pending result set */
+static my_bool madb_have_pending_results(MYSQL_STMT *stmt)
+{
+  LIST *li_stmt= stmt->mysql->stmts;
+  for (;li_stmt;li_stmt= li_stmt->next)
+  {
+    MYSQL_STMT *s= (MYSQL_STMT *)li_stmt->data;
+    if (s != stmt && s->state == MYSQL_STMT_WAITING_USE_OR_STORE)
+      return 1;
+  }
+  return 0;
+}
+
 my_bool mthd_supported_buffer_type(enum enum_field_types type)
 {
   switch (type) {
@@ -1489,6 +1503,12 @@ my_bool STDCALL mysql_stmt_close(MYSQL_STMT *stmt)
 {
   my_bool rc= 1;
 
+  if (madb_have_pending_results(stmt))
+  {
+    stmt_set_error(stmt, CR_COMMANDS_OUT_OF_SYNC, SQLSTATE_UNKNOWN, 0);
+    return 1;
+  }
+
   if (stmt)
   {
     if (stmt->mysql && stmt->mysql->net.pvio)
@@ -2208,14 +2228,10 @@ static my_bool madb_reset_stmt(MYSQL_STMT *stmt, unsigned int flags)
 
   /* CONC-667: If an other statement has a pending result set, we
      need to return an error */
-  for (;li_stmt;li_stmt= li_stmt->next)
+  if (madb_have_pending_results(stmt))
   {
-    MYSQL_STMT *s= (MYSQL_STMT *)li_stmt->data;
-    if (s != stmt && s->state == MYSQL_STMT_WAITING_USE_OR_STORE)
-    {
-      stmt_set_error(stmt, CR_COMMANDS_OUT_OF_SYNC, SQLSTATE_UNKNOWN, 0);
-      return 1;
-    }
+    stmt_set_error(stmt, CR_COMMANDS_OUT_OF_SYNC, SQLSTATE_UNKNOWN, 0);
+    return 1;
   }
 
   if (!stmt->mysql)
diff --git a/unittest/libmariadb/ps_bugs.c b/unittest/libmariadb/ps_bugs.c
index 562ea3ff..0623f088 100644
--- a/unittest/libmariadb/ps_bugs.c
+++ b/unittest/libmariadb/ps_bugs.c
@@ -5780,7 +5780,37 @@ static int test_conc667(MYSQL *mysql)
   return OK;
 }
 
+static int test_conc683(MYSQL *mysql)
+{
+  MYSQL_STMT *stmt1, *stmt2;
+  int rc;
+
+  stmt1= mysql_stmt_init(mysql);
+  stmt2= mysql_stmt_init(mysql);
+
+  rc= mysql_stmt_prepare(stmt1, "SELECT 1 UNION SELECT 2", -1);
+  check_stmt_rc(rc, stmt1);
+
+  rc= mysql_stmt_prepare(stmt2, "SELECT 1", -1);
+  check_stmt_rc(rc, stmt2);
+
+  rc= mysql_stmt_execute(stmt1);
+  check_stmt_rc(rc, stmt1);
+
+  rc= mysql_stmt_close(stmt2);
+  FAIL_IF(!rc || mysql_stmt_errno(stmt2) != CR_COMMANDS_OUT_OF_SYNC,
+           "Expected commands out of sync error");
+
+  rc= mysql_stmt_close(stmt1);
+  check_stmt_rc(rc, stmt1);
+  rc= mysql_stmt_close(stmt2);
+  check_stmt_rc(rc, stmt2);
+
+  return OK;
+}
+
 struct my_tests_st my_tests[] = {
+  {"test_conc683", test_conc683, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_conc667", test_conc667, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_conc633", test_conc633, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_conc623", test_conc623, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},