fix(mssql): unexpected error event when connect fails, crashing node process (#10762)

lib/dialects/mssql/connection-manager.js

@@ -90,11 +90,14 @@ class ConnectionManager extends AbstractConnectionManager {
       connection.once('end', endHandler);
       connection.once('connect', connectHandler);
 
-      if (config.dialectOptions && config.dialectOptions.debug) {
-        connection.on('debug', debugTedious.log.bind(debugTedious));
-      }
-    }).tap(resourceLock => {
-      const connection = resourceLock.unwrap();
+      /*
+       * Permanently attach this event before connection is even acquired
+       * tedious sometime emits error even after connect(with error).
+       *
+       * If we dont attach this even that unexpected error event will crash node process
+       *
+       * E.g. connectTimeout is set higher than requestTimeout
+       */
       connection.on('error', error => {
         switch (error.code) {
           case 'ESOCKET':
@@ -102,6 +105,10 @@ class ConnectionManager extends AbstractConnectionManager {
             this.pool.destroy(resourceLock);
         }
       });
+
+      if (config.dialectOptions && config.dialectOptions.debug) {
+        connection.on('debug', debugTedious.log.bind(debugTedious));
+      }
     }).catch(error => {
       if (!error.code) {
         throw new sequelizeErrors.ConnectionError(error);