PHP array constructors for protobuf messages (#4530)

* PHP array constructors for protobuf messages

* removes Descriptor from error message

* allows mergeFrom to accept an array

* only use initWithDescriptor if instanceof MapEntry

* adds doc comments

* removes ability for constructors to take arrays for submessages

* Revert "allows mergeFrom to accept an array"

This reverts commit b7b72182d561634af12c5c5c56a7cda3b33241f9.

* makes mergeFromArray protected and fixes mergeFrom whitespace

* Separates merging from JSON and merging from PHP array

* removes well-known types and json keys from array construction

* Addresses PR review comments

* cleans up tests

* fixes exception messages

1 files changed, 20 insertions, 2 deletions

diff --git a/php/src/Google/Protobuf/Internal/MethodDescriptorProto.php b/php/src/Google/Protobuf/Internal/MethodDescriptorProto.php
index ccfce2db..1bd5dd3e 100644
--- a/php/src/Google/Protobuf/Internal/MethodDescriptorProto.php
+++ b/php/src/Google/Protobuf/Internal/MethodDescriptorProto.php
@@ -55,9 +55,27 @@ class MethodDescriptorProto extends \Google\Protobuf\Internal\Message
     private $server_streaming = false;
     private $has_server_streaming = false;
 
-    public function __construct() {
+    /**
+     * Constructor.
+     *
+     * @param array $data {
+     *     Optional. Data for populating the Message object.
+     *
+     *     @type string $name
+     *     @type string $input_type
+     *           Input and output type names.  These are resolved in the same way as
+     *           FieldDescriptorProto.type_name, but must refer to a message type.
+     *     @type string $output_type
+     *     @type \Google\Protobuf\Internal\MethodOptions $options
+     *     @type bool $client_streaming
+     *           Identifies if client streams multiple client messages
+     *     @type bool $server_streaming
+     *           Identifies if server streams multiple server messages
+     * }
+     */
+    public function __construct($data = NULL) {
         \GPBMetadata\Google\Protobuf\Internal\Descriptor::initOnce();
-        parent::__construct();
+        parent::__construct($data);
     }
 
     /**