Ensure namespaced fieldsets are returned (#407)

* Ensure namespaced fieldsets are not ignored

* Ensure blueprintTest only tests blueprints

* Update test

* Same for blueprints

* wrong variable

* Revert the fix for namespaced blueprints

---------

Co-authored-by: Duncan McClean <[email protected]>

Author: ryanmitchell

src/Fields/FieldsetRepository.php

@@ -30,7 +30,8 @@ public function all(): Collection
                         ->setContents($model->data);
                 });
             });
-        });
+        })
+            ->merge($this->getNamespacedFieldsets());
     }
 
     public function find($handle): ?Fieldset

tests/Data/Fields/FieldsetTest.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Tests\Data\Fields;
+
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use PHPUnit\Framework\Attributes\Test;
+use Statamic\Facades\Fieldset;
+use Tests\TestCase;
+
+class FieldsetTest extends TestCase
+{
+    use RefreshDatabase;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->app->singleton(
+            'Statamic\Fields\FieldsetRepository',
+            'Statamic\Eloquent\Fields\FieldsetRepository'
+        );
+
+        $this->app->bind('statamic.eloquent.fieldsets.model', function () {
+            return \Statamic\Eloquent\Fields\FieldsetModel::class;
+        });
+    }
+
+    #[Test]
+    public function it_handles_fieldsets_registered_by_addons()
+    {
+        $this->assertCount(0, Fieldset::all());
+
+        Fieldset::addNamespace(
+            'my-addon',
+            directory: __DIR__.'/../../__fixtures__/resources/fieldsets'
+        );
+
+        $this->assertCount(1, Fieldset::all());
+        $this->assertSame('my-addon::seo', Fieldset::all()->first()->handle());
+    }
+}

tests/__fixtures__/resources/fieldsets/seo.yaml

@@ -0,0 +1,30 @@
+title: 'Advanced SEO (Sitemap)'
+fields:
+  -
+    handle: seo_section_sitemap
+    field:
+      type: advanced_seo
+      display: 'Sitemap'
+      field: seo_section_sitemap
+      visibility: hidden
+  -
+    handle: seo_sitemap_enabled
+    field:
+      type: advanced_seo
+      display: 'Enabled'
+      field: seo_sitemap_enabled
+      visibility: hidden
+  -
+    handle: seo_sitemap_priority
+    field:
+      type: advanced_seo
+      display: 'Priority'
+      field: seo_sitemap_priority
+      visibility: hidden
+  -
+    handle: seo_sitemap_change_frequency
+    field:
+      type: advanced_seo
+      display: 'Change Frequency'
+      field: seo_sitemap_change_frequency
+      visibility: hidden