[5.4] Add tag filter none (joomla#45274)

Add a new filter option when filtering for tags that allows you to filter all articles that have no tags at all.

---------

Co-authored-by: Richard Fath <[email protected]>

Author: brianteeman

administrator/components/com_content/forms/filter_articles.xml

@@ -92,13 +92,16 @@
 		<field
 			name="tag"
 			type="tag"
-			multiple="true"
 			label="JTAG"
-			hint="JOPTION_SELECT_TAG"
+			multiple="true"
 			mode="nested"
 			custom="false"
+			hint="JOPTION_SELECT_TAG"
 			class="js-select-submit-on-change"
-		/>
+			default=""
+			>
+			<option value="0">JNONE_FILTER</option>
+		</field>
 
 		<field
 			name="level"

administrator/components/com_content/forms/filter_featured.xml

@@ -84,7 +84,10 @@
 			custom="false"
 			hint="JOPTION_SELECT_TAG"
 			class="js-select-submit-on-change"
-		/>
+			default=""
+			>
+			<option value="0">JNONE_FILTER</option>
+		</field>
 
 		<field
 			name="level"

administrator/components/com_content/src/Model/ArticlesModel.php

@@ -491,7 +491,13 @@ protected function getListQuery()
         }
 
         if ($tag && \is_array($tag)) {
-            $tag = ArrayHelper::toInteger($tag);
+            $tag         = ArrayHelper::toInteger($tag);
+            $includeNone = false;
+
+            if (\in_array(0, $tag)) {
+                $tag         = array_filter($tag);
+                $includeNone = true;
+            }
 
             $subQuery = $db->getQuery(true)
                 ->select('DISTINCT ' . $db->quoteName('content_item_id'))
@@ -504,23 +510,56 @@ protected function getListQuery()
                 );
 
             $query->join(
-                'INNER',
+                $includeNone ? 'LEFT' : 'INNER',
                 '(' . $subQuery . ') AS ' . $db->quoteName('tagmap'),
                 $db->quoteName('tagmap.content_item_id') . ' = ' . $db->quoteName('a.id')
             );
-        } elseif ($tag = (int) $tag) {
-            $query->join(
-                'INNER',
-                $db->quoteName('#__contentitem_tag_map', 'tagmap'),
-                $db->quoteName('tagmap.content_item_id') . ' = ' . $db->quoteName('a.id')
-            )
+
+            if ($includeNone) {
+                $subQuery2 = $db->getQuery(true)
+                    ->select('DISTINCT ' . $db->quoteName('content_item_id'))
+                    ->from($db->quoteName('#__contentitem_tag_map'))
+                    ->where($db->quoteName('type_alias') . ' = ' . $db->quote('com_content.article'));
+                $query->join(
+                    'LEFT',
+                    '(' . $subQuery2 . ') AS ' . $db->quoteName('tagmap2'),
+                    $db->quoteName('tagmap2.content_item_id') . ' = ' . $db->quoteName('a.id')
+                )
+                ->where(
+                    '(' . $db->quoteName('tagmap.content_item_id') . ' IS NOT NULL OR '
+                    . $db->quoteName('tagmap2.content_item_id') . ' IS NULL)'
+                );
+            }
+        } elseif (is_numeric($tag)) {
+            $tag = (int) $tag;
+
+            if ($tag === 0) {
+                $subQuery = $db->getQuery(true)
+                    ->select('DISTINCT ' . $db->quoteName('content_item_id'))
+                    ->from($db->quoteName('#__contentitem_tag_map'))
+                    ->where($db->quoteName('type_alias') . ' = ' . $db->quote('com_content.article'));
+
+                // Only show articles without tags
+                $query->join(
+                    'LEFT',
+                    '(' . $subQuery . ') AS ' . $db->quoteName('tagmap'),
+                    $db->quoteName('tagmap.content_item_id') . ' = ' . $db->quoteName('a.id')
+                )
+                ->where($db->quoteName('tagmap.content_item_id') . ' IS NULL');
+            } else {
+                $query->join(
+                    'INNER',
+                    $db->quoteName('#__contentitem_tag_map', 'tagmap'),
+                    $db->quoteName('tagmap.content_item_id') . ' = ' . $db->quoteName('a.id')
+                )
                 ->where(
                     [
                         $db->quoteName('tagmap.tag_id') . ' = :tag',
                         $db->quoteName('tagmap.type_alias') . ' = ' . $db->quote('com_content.article'),
                     ]
                 )
                 ->bind(':tag', $tag, ParameterType::INTEGER);
+            }
         }
 
         // Add the list ordering clause.