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, 11 insertions, 2 deletions

diff --git a/php/src/Google/Protobuf/Internal/FileDescriptorSet.php b/php/src/Google/Protobuf/Internal/FileDescriptorSet.php
index 0b2cf957..9907b17d 100644
--- a/php/src/Google/Protobuf/Internal/FileDescriptorSet.php
+++ b/php/src/Google/Protobuf/Internal/FileDescriptorSet.php
@@ -24,9 +24,18 @@ class FileDescriptorSet extends \Google\Protobuf\Internal\Message
     private $file;
     private $has_file = false;
 
-    public function __construct() {
+    /**
+     * Constructor.
+     *
+     * @param array $data {
+     *     Optional. Data for populating the Message object.
+     *
+     *     @type \Google\Protobuf\Internal\FileDescriptorProto[]|\Google\Protobuf\Internal\RepeatedField $file
+     * }
+     */
+    public function __construct($data = NULL) {
         \GPBMetadata\Google\Protobuf\Internal\Descriptor::initOnce();
-        parent::__construct();
+        parent::__construct($data);
     }
 
     /**