Resolves Issue 3992

* Fixed connection lost error when fast forward flag is off.
* Added tap test for regression testing.

test/tap/tests/reg_test_3992_fast_forward_malformed_packet-mysqlsh-t.cpp

@@ -0,0 +1,48 @@
+/**
+ * @file reg_test_3992-fast_forward_malformed_packet-t.cpp
+ * @brief This is a regression test for issue #3992. Test checks if queries are executed successfully with MariaDB  
+ *  server via mysql client having fast forward flag set to true and false.
+ * @details The test executes basic queries to check execution in MariaDB via mysql client with Fast Forward flags on/off
+ *   
+ */
+
+#include <vector>
+#include <string>
+#include <stdio.h>
+#include <cstring>
+#include <unistd.h>
+#include <mysql.h>
+
+#include "tap.h"
+#include "command_line.h"
+#include "utils.h"
+
+int main(int argc, char** argv) {
+	CommandLine cl;
+
+	if (cl.getEnv()) {
+		diag("Failed to get the required environmental variables.");
+		return -1;
+	}
+	
+	const std::vector<std::pair<std::string, std::string>> users { {"mariadbuserff", "mariadbuserff"},
+											   {"mariadbuser", "mariadbuser"} };
+
+	for (const auto& user : users)
+	{
+		// Test that mysqlsh is able to connect and execute a query
+		const char* mysqlsh_client = "mysqlsh";
+		const std::string mysql_user = std::string("-u") + user.first + " ";
+		const std::string mysql_pass = std::string("-p") + user.second + " ";
+		const std::string mysql_port = std::string("-P") + std::to_string(cl.port) + " ";
+		const std::string host = std::string("-h ") + std::string(cl.host) + " ";
+
+		int mysqlsh_res = system((std::string("mysqlsh ") + std::string("--sql ") + mysql_user + mysql_pass + mysql_port + host + "-e \"SHOW DATABASES\"").c_str());
+		ok(mysqlsh_res == 0, "'mysqlsh' empty select command should be correctly executed. Err code was: %d", mysqlsh_res);
+
+		mysqlsh_res = system((std::string("mysqlsh ") + std::string("--sql ") + mysql_user + mysql_pass + mysql_port + host + "-e \"SELECT 1\"").c_str());
+		ok(mysqlsh_res == 0, "'mysqlsh' empty select command should be correctly executed. Err code was: %d", mysqlsh_res);
+	}
+
+	return exit_status();
+}