add noOverrideParameters method not to override parameter

src/Transport/Sendmail.php

@@ -42,6 +42,11 @@ class Sendmail implements TransportInterface
      */
     protected $operatingSystem;
 
+    /**
+     * @var boolean
+     */
+    protected $noOverrideParameters;
+
     /**
      * Constructor.
      *
@@ -53,6 +58,7 @@ public function __construct($parameters = null)
             $this->setParameters($parameters);
         }
         $this->callable = [$this, 'mailHandler'];
+        $this->noOverrideParameter = false;
     }
 
     /**
@@ -259,6 +265,9 @@ protected function prepareParameters(Mail\Message $message)
         }
 
         $parameters = (string) $this->parameters;
+        if ($this->noOverrideParameters) {
+            return $parameters;
+        }
 
         $sender = $message->getSender();
         if ($sender instanceof AddressInterface) {
@@ -322,6 +331,11 @@ public function handleMailErrors($errno, $errstr, $errfile = null, $errline = nu
         return true;
     }
 
+    public function noOverrideParameters()
+    {
+        $this->noOverrideParameters = true;
+    }
+
     /**
      * Is this a windows OS?
      *

test/Transport/SendmailTest.php

@@ -252,4 +252,18 @@ public function testDoNotAllowMessageWithoutToAndCcAndBccHeaders()
         $this->expectException(RuntimeException::class);
         $this->transport->send($message);
     }
+
+    public function testNotOverrideParameters()
+    {
+        if ($this->operating_system == 'WIN') {
+            $this->markTestSkipped('This test is *nix-specific');
+        }
+
+        $message = $this->getMessage();
+        $this->transport->noOverrideParameters();
+        $this->transport->setParameters('-f\'[email protected]\'');
+
+        $this->transport->send($message);
+        $this->assertEquals('-f\'[email protected]\'', $this->additional_parameters);
+    }
 }