Fix HTML renderer not able to handle metadata of a row (#11991)

core/DataTable/Renderer/Html.php

@@ -117,6 +117,8 @@ class Html extends Renderer
             foreach ($row->getMetadata() as $name => $value) {
                 if (is_string($value)) {
                     $value = "'$value'";
+                } else if (is_array($value)) {
+                    $value = var_export($value, true);
                 }
                 $metadata[] = "'$name' => $value";
             }

plugins/API/tests/Unit/HtmlRendererTest.php

@@ -9,7 +9,9 @@
 namespace Piwik\Plugins\API\tests\Unit;
 
 use Piwik\DataTable;
+use Piwik\Date;
 use Piwik\Plugins\API\Renderer\Html;
+use Piwik\Plugins\CoreHome\Columns\Metrics\AverageTimeOnSite;
 
 /**
  * @group Plugin
@@ -258,6 +260,52 @@ message', $response);
 ', $response);
     }
 
+    public function test_renderDataTable_shouldRenderDataTableWithComplexMetadata()
+    {
+        $dataTable = new DataTable\Simple();
+        $row = new DataTable\Row();
+        $row->setColumn('nb_visits', 3);
+        $row->setColumn('nb_random', 6);
+        $row->setMetadata('processedRows', [
+            new AverageTimeOnSite(),
+            new \stdClass(),
+            Date::factory('2016-01-01 00:00:00')
+        ]);
+        $dataTable->addRow($row);
+
+        $response = $this->builder->renderDataTable($dataTable);
+
+        $this->assertEquals('<table id="MultiSites_getAll" border="1">
+<thead>
+	<tr>
+		<th>nb_visits</th>
+		<th>nb_random</th>
+		<th>_metadata</th>
+	</tr>
+</thead>
+<tbody>
+	<tr>
+		<td>3</td>
+		<td>6</td>
+		<td>\'processedRows\' =&gt; array (
+  0 =&gt; 
+  Piwik\Plugins\CoreHome\Columns\Metrics\AverageTimeOnSite::__set_state(array(
+  )),
+  1 =&gt; 
+  stdClass::__set_state(array(
+  )),
+  2 =&gt; 
+  Piwik\Date::__set_state(array(
+     \'timestamp\' =&gt; 1451606400,
+     \'timezone\' =&gt; \'UTC\',
+  )),
+)</td>
+	</tr>
+</tbody>
+</table>
+', $response);
+    }
+
     public function test_renderArray_ShouldConvertSimpleArrayToJson()
     {
         $input = array(1, 2, 5, 'string', 10);