[CONJS-256] changeUser can lead to error when using multi-authenticat…

…ion and pipelining

lib/cmd/change-user.js

@@ -7,15 +7,15 @@ const Capabilities = require('../const/capabilities');
 const Ed25519PasswordAuth = require('./handshake/auth/ed25519-password-auth');
 const NativePasswordAuth = require('./handshake/auth/native-password-auth');
 const Collations = require('../const/collations');
-const Handshake = require('./handshake/authentication');
+const Authentication = require('./handshake/authentication');
 
 /**
  * send a COM_CHANGE_USER: resets the connection and re-authenticates with the given credentials
  * see https://mariadb.com/kb/en/library/com_change_user/
  */
-class ChangeUser extends Handshake {
-  constructor(cmdParam, connOpts, resolve, reject, addCommand) {
-    super(cmdParam, resolve, reject, () => {}, addCommand);
+class ChangeUser extends Authentication {
+  constructor(cmdParam, connOpts, resolve, reject, getSocket) {
+    super(cmdParam, resolve, reject, () => {}, getSocket);
     this.configAssign(connOpts, cmdParam.opts);
   }
 
@@ -104,7 +104,7 @@ class ChangeUser extends Handshake {
     }
 
     out.flush();
-    this.onPacketReceive = this.handshakeResult;
+    this.plugin.onPacketReceive = this.handshakeResult.bind(this);
   }
 
   /**

lib/connection.js

@@ -1239,17 +1239,18 @@ class Connection extends EventEmitter {
       reject(err);
       return;
     }
-
+    this.addCommand = this.addCommandEnable;
     this.addCommand(
       new ChangeUser(
         cmdParam,
         this.opts,
         (res) => {
+          if (this.opts.pipelining) this.addCommand = this.addCommandEnablePipeline;
           if (cmdParam.opts && cmdParam.opts.collation) this.opts.collation = cmdParam.opts.collation;
           resolve(res);
         },
         this.authFailHandler.bind(this, reject),
-        this.addCommand.bind(this)
+        this.getSocket.bind(this)
       )
     );
   }