Disassociate child tag when parent is deleted. fixes flarum/core#962

extensions/tags/js/admin/dist/extension.js

@@ -793,11 +793,26 @@ System.register('flarum/tags/components/EditTagModal', ['flarum/components/Modal
         }, {
           key: 'delete',
           value: function _delete() {
+            var _this4 = this;
+
             if (confirm(app.translator.trans('flarum-tags.admin.edit_tag.delete_tag_confirmation'))) {
-              this.tag.delete().then(function () {
+              (function () {
-                return m.redraw();
+                var children = app.store.all('tags').filter(function (tag) {
+                  return tag.parent() === _this4.tag;
                 });
-              this.hide();
+
+                _this4.tag.delete().then(function () {
+                  children.forEach(function (tag) {
+                    return tag.pushData({
+                      attributes: { isChild: false },
+                      relationships: { parent: null }
+                    });
+                  });
+                  m.redraw();
+                });
+
+                _this4.hide();
+              })();
             }
           }
         }]);

extensions/tags/js/admin/src/components/EditTagModal.js

@@ -110,7 +110,16 @@ export default class EditTagModal extends Modal {
 
   delete() {
     if (confirm(app.translator.trans('flarum-tags.admin.edit_tag.delete_tag_confirmation'))) {
-      this.tag.delete().then(() => m.redraw());
+      const children = app.store.all('tags').filter(tag => tag.parent() === this.tag);
+
+      this.tag.delete().then(() => {
+        children.forEach(tag => tag.pushData({
+          attributes: {isChild: false},
+          relationships: {parent: null}
+        }));
+        m.redraw();
+      });
+
       this.hide();
     }
   }

extensions/tags/src/Command/DeleteTagHandler.php

@@ -44,6 +44,10 @@ class DeleteTagHandler
 
         $this->assertCan($actor, 'delete', $tag);
 
+        $this->tags->query()
+            ->where('parent_id', $tag->id)
+            ->update(['parent_id' => null]);
+
         $tag->delete();
 
         return $tag;

extensions/tags/src/Tag.php

@@ -143,7 +143,7 @@ class Tag extends AbstractModel
         foreach ($tags as $tag) {
             $can = $canForTag($tag);
 
-            if ($can && $tag->parent_id) {
+            if ($can && $tag->parent) {
                 $can = $canForTag($tag->parent);
             }
 

extensions/tags/src/TagRepository.php

@@ -16,6 +16,16 @@ use Illuminate\Database\Eloquent\Builder;
 
 class TagRepository
 {
+    /**
+     * Get a new query builder for the tags table.
+     *
+     * @return Builder
+     */
+    public function query()
+    {
+        return Tag::query();
+    }
+
     /**
      * Find a tag by ID, optionally making sure it is visible to a certain
      * user, or throw an exception.