Always initialize empty namespace for collectables

Fixes #117

example/_config.yml

@@ -5,6 +5,8 @@ collections:
     folder: _posts
   - name: books
     folder: _books
+  - name: empty-collection
+    folder: _empty-collection
 
 categories:
   - features

example/_pages/empty-category.html.twig

@@ -0,0 +1,7 @@
+---
+name: Empty Collection Page
+collection: empty-collection
+permalink: /empty/%title/
+---
+
+{{ this.title }}

src/allejo/stakx/Manager/CollectionManager.php

@@ -164,6 +164,7 @@ public function parseCollections($collections)
                 sprintf('/\.(%s)$/', implode('|', $this->markupEngineManager->getSupportedExtensions())),
             ];
 
+            $this->declareTrackingNamespace($collection['name']);
             $this->scanTrackableItems($def, [
                 'namespace' => $collection['name'],
             ]);

src/allejo/stakx/Manager/DataManager.php

@@ -143,6 +143,7 @@ public function parseDataSets($dataSets)
             $this->eventDispatcher->dispatch(DatasetDefinitionAdded::NAME, $event);
 
             $def = new FileExplorerDefinition($folder);
+            $this->declareTrackingNamespace($dataSet['name']);
             $this->scanTrackableItems($def, [
                 'namespace' => $dataSet['name'],
             ]);

src/allejo/stakx/Manager/PageManager.php

@@ -219,6 +219,7 @@ public function trackNewPageView(BasePageView $pageView)
         $event = new PageViewAdded($pageView);
         $this->eventDispatcher->dispatch(PageViewAdded::NAME, $event);
 
+        $this->declareTrackingNamespace($namespace);
         $this->addObjectToTracker($pageView, $namespace);
     }
 

src/allejo/stakx/Manager/TrackingManager.php

@@ -162,6 +162,19 @@ public function refreshItem($filePath)
     // Internal object handling
     ///
 
+    /**
+     * Initialize a namespace that will be tracked.
+     *
+     * @param string $namespace
+     */
+    protected function declareTrackingNamespace($namespace)
+    {
+        if (!isset($this->trackedItems[$namespace]))
+        {
+            $this->trackedItems[$namespace] = [];
+        }
+    }
+
     protected function addFileToTracker(File &$file)
     {
         $this->trackedItemsFlattened[$file->getRelativeFilePath()] = &$file;