Merge pull request #95 from neo4j-php/additional_version_check

Additional version check

Author: stefanak-michal

src/Bolt.php

@@ -61,7 +61,9 @@ public function build(): AProtocol
      */
     public function setProtocolVersions(...$v): Bolt
     {
-        $this->versions = $v;
+        $this->versions = array_slice($v, 0, 4);
+        while (count($this->versions) < 4)
+            $this->versions[] = 0;
         return $this;
     }
 
@@ -109,9 +111,9 @@ private function handshake(): string
 
     /**
      * Read and compose selected protocol version
-     * @return string
+     * @return string|null
      */
-    private function unpackProtocolVersion(): string
+    private function unpackProtocolVersion(): ?string
     {
         $result = [];
 
@@ -123,7 +125,8 @@ private function unpackProtocolVersion(): string
             array_shift($result);
         }
 
-        return implode('.', array_reverse($result));
+        $version = implode('.', array_reverse($result));
+        return in_array($version, $this->versions) ? $version : null;
     }
 
     /**
@@ -134,9 +137,6 @@ private function packProtocolVersions(): string
     {
         $versions = [];
 
-        while (count($this->versions) < 4)
-            $this->versions[] = '0';
-
         foreach ($this->versions as $v) {
             if (is_int($v))
                 $versions[] = pack('N', $v);