Fix wait_timeout timeout calculations and add proper newline characters

Key improvements:
- Fix timeout comparison in MySQL_Thread::idle_thread_to_kill_idle_sessions() to prevent underflow
- Use effective wait_timeout (minimum of global and session values) for idle timeout calculations
- Add proper newline characters to proxy_warning messages for consistent log formatting
- Increase test sleep times to account for global timeout enforcement
- Fix session timeout test durations to properly test timeout behavior

Technical changes:
- Replace broken min_idle calculation with proper effective wait_timeout logic
- Add std::min() usage to determine effective timeout from global and session values
- Ensure warning messages end with newline characters for proper log formatting
- Update test sleep durations to ensure proper timeout testing

Resolves potential timeout calculation bugs and ensures consistent timeout enforcement behavior.

lib/MySQL_Session.cpp

@@ -6627,7 +6627,7 @@ bool MySQL_Session::handler___status_WAITING_CLIENT_DATA___STATE_SLEEP___MYSQL_C
 
 						// Warn if value was clamped due to ProxySQL limits
 						if (original_timeout != client_timeout) {
-							proxy_warning("Client [%s] (user: %s) requested wait_timeout = %llu ms, clamped to %llu ms (ProxySQL limits: 1s to 20 days)",
+							proxy_warning("Client [%s] (user: %s) requested wait_timeout = %llu ms, clamped to %llu ms (ProxySQL limits: 1s to 20 days)\n",
 											client_myds->myconn->connected_host_details.ip,
 											client_myds->myconn->userinfo->username,
 											original_timeout,
@@ -6636,7 +6636,7 @@ bool MySQL_Session::handler___status_WAITING_CLIENT_DATA___STATE_SLEEP___MYSQL_C
 
 						// Warn if client's value exceeds current global timeout (after clamping)
 						if (client_timeout > static_cast<unsigned long long>(mysql_thread___wait_timeout)) {
-							proxy_warning("Client [%s] (user: %s) requested wait_timeout = %llu ms, exceeds the global mysql-wait_timeout = %d ms. Global timeout will still be enforced.",
+							proxy_warning("Client [%s] (user: %s) requested wait_timeout = %llu ms, exceeds the global mysql-wait_timeout = %d ms. Global timeout will still be enforced.\n",
 											client_myds->myconn->connected_host_details.ip,
 											client_myds->myconn->userinfo->username,
 											client_timeout,

lib/MySQL_Thread.cpp

@@ -3436,15 +3436,25 @@ void MySQL_Thread::idle_thread_to_kill_idle_sessions() {
 		mysess_idx=0;
 	}
 	unsigned int i;
-	unsigned long long min_idle = 0;
-	if (curtime > (unsigned long long)mysql_thread___wait_timeout*1000) {
-		min_idle = curtime - (unsigned long long)mysql_thread___wait_timeout*1000;
+	if (curtime < (unsigned long long)mysql_thread___wait_timeout*1000) {
+		return; // this should never happen
+		//min_idle = curtime - (unsigned long long)mysql_thread___wait_timeout*1000;
 	}
 	for (i=0;i<SESS_TO_SCAN && mysess_idx < mysql_sessions->len; i++) {
 		uint32_t sess_pos=mysess_idx;
 		MySQL_Session *mysess=(MySQL_Session *)mysql_sessions->index(sess_pos);
-		if (mysess->idle_since < min_idle || mysess->killed==true) {
+		unsigned long long effective_wait_timeout = std::min(
+			static_cast<unsigned long long>(mysql_thread___wait_timeout),
+			static_cast<unsigned long long>(mysess->wait_timeout)
+		);
+		unsigned long long min_idle = 0;
+		min_idle = curtime - (unsigned long long)effective_wait_timeout*1000;
+		if (mysess->idle_since < min_idle) {
+			unsigned long long sess_time = curtime - mysess->idle_since;
+			proxy_warning("Killing client connection %s:%d because inactive for %llums\n", mysess->client_myds->addr.addr, mysess->client_myds->addr.port, sess_time/1000);
 			mysess->killed=true;
+		}
+		if (mysess->killed==true) { // because idle or for any other reason
 			MySQL_Data_Stream *tmp_myds=mysess->client_myds;
 			int dsidx=tmp_myds->poll_fds_idx;
 			//fprintf(stderr,"Removing session %p, DS %p idx %d\n",mysess,tmp_myds,dsidx);
@@ -4053,7 +4063,11 @@ void MySQL_Thread::process_all_sessions() {
 #ifdef IDLE_THREADS
 				else
 			{
-				if ( (sess_time/1000 > (unsigned long long)mysql_thread___wait_timeout) ) {
+				unsigned long long effective_wait_timeout = std::min(
+					static_cast<unsigned long long>(mysql_thread___wait_timeout),
+					static_cast<unsigned long long>(sess->wait_timeout)
+				);
+				if ( (sess_time/1000 > effective_wait_timeout) ) {
 					sess->killed=true;
 					sess->to_process=1;
 					proxy_warning("Killing client connection %s:%d because inactive for %llums\n", sess->client_myds->addr.addr, sess->client_myds->addr.port, sess_time/1000);

test/tap/tests/mysql-set_wait_timeout-t.cpp

@@ -72,7 +72,7 @@ int test_session_timeout(CommandLine *cl, MYSQL *admin) {
 	int rc = run_q(proxy, "SET sql_mode=''");
 	ok(rc == 0, (rc == 0 ? "Connection alive" : "Connection killed"));
 
-	sleep(12);
+	sleep(25);
 
 	rc = run_q(proxy, "SET sql_mode=''");
 	ok(rc != 0, (rc == 0 ? "Connection alive" : "Connection killed"));
@@ -99,7 +99,7 @@ int test_session_timeout_exceed_global_timeout(CommandLine *cl, MYSQL *admin) {
 	int rc = run_q(proxy, "SET sql_mode=''");
 	ok(rc == 0, (rc == 0 ? "Connection alive" : "Connection killed"));
 
-	sleep(12);
+	sleep(15);
 
 	rc = run_q(proxy, "SET sql_mode=''");
 	ok(rc != 0, (rc == 0 ? "Connection alive" : "Connection killed"));