[5.x] Prevents Recursive Fieldsets

resources/lang/en/validation.php

@@ -169,6 +169,7 @@
     'duplicate_field_handle' => 'A field with a handle of :handle already exists.',
     'duplicate_uri' => 'Duplicate URI :value',
     'email_available' => 'A user with this email already exists.',
+    'fieldset_imported_recursively' => 'Fieldset :handle is being imported recursively.',
     'one_site_without_origin' => 'At least one site must not have an origin.',
     'options_require_keys' => 'All options must have keys.',
     'origin_cannot_be_disabled' => 'Cannot select a disabled origin.',

src/Exceptions/FieldsetRecursionException.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Statamic\Exceptions;
+
+use Exception;
+use Spatie\Ignition\Contracts\BaseSolution;
+use Spatie\Ignition\Contracts\ProvidesSolution;
+use Spatie\Ignition\Contracts\Solution;
+
+class FieldsetRecursionException extends Exception implements ProvidesSolution
+{
+    public function __construct(private string $fieldset, private string $target)
+    {
+        parent::__construct("Fieldset [$fieldset] is being imported recursively.");
+    }
+
+    public function getFieldset()
+    {
+        return $this->fieldset;
+    }
+
+    public function getSolution(): Solution
+    {
+        return BaseSolution::create('Avoid infinite recursion')
+            ->setSolutionDescription("The fieldset `$this->fieldset` is being imported into `$this->target`, however it has already been imported elsewhere. This is causing infinite recursion.");
+    }
+}

src/Fields/Fields.php

@@ -268,9 +268,11 @@ private function getReferencedField(array $config): Field
 
     private function getImportedFields(array $config): array
     {
+        $recursion = tap(app(FieldsetRecursionStack::class))->push($config['import']);
+
         $blink = 'blueprint-imported-fields-'.md5(json_encode($config));
 
-        return Blink::once($blink, function () use ($config) {
+        $imported = Blink::once($blink, function () use ($config) {
             if (! $fieldset = FieldsetRepository::find($config['import'])) {
                 throw new FieldsetNotFoundException($config['import']);
             }
@@ -299,6 +301,10 @@ private function getImportedFields(array $config): array
                 ->setParent($this->parent)
                 ->setParentField($this->parentField, $this->parentIndex);
         })->all();
+
+        $recursion->pop();
+
+        return $imported;
     }
 
     public function meta()

src/Fields/Fieldset.php

@@ -8,6 +8,7 @@
 use Statamic\Events\FieldsetDeleting;
 use Statamic\Events\FieldsetSaved;
 use Statamic\Events\FieldsetSaving;
+use Statamic\Exceptions\FieldsetRecursionException;
 use Statamic\Facades;
 use Statamic\Facades\AssetContainer;
 use Statamic\Facades\Collection;
@@ -85,6 +86,14 @@ public function title()
         return $this->contents['title'] ?? Str::humanize(Str::of($this->handle)->after('::')->afterLast('.'));
     }
 
+    /**
+     * @throws FieldsetRecursionException
+     */
+    public function validateRecursion()
+    {
+        $this->fields();
+    }
+
     public function fields(): Fields
     {
         $fields = Arr::get($this->contents, 'fields', []);

src/Fields/FieldsetRecursionStack.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Statamic\Fields;
+
+use Illuminate\Support\Collection;
+use Statamic\Exceptions\FieldsetRecursionException;
+
+class FieldsetRecursionStack
+{
+    public function __construct(private Collection $stack)
+    {
+        $this->stack = collect();
+    }
+
+    public function push(string $import)
+    {
+        if ($this->stack->contains($import)) {
+            throw new FieldsetRecursionException($import, $this->stack->last());
+        }
+
+        $this->stack->push($import);
+    }
+
+    public function pop()
+    {
+        $this->stack->pop();
+    }
+}

src/Http/Controllers/CP/Fields/FieldsetController.php

@@ -74,6 +74,8 @@ public function edit($fieldset)
     {
         $fieldset = Facades\Fieldset::find($fieldset);
 
+        $fieldset->validateRecursion();
+
         $vue = [
             'title' => $fieldset->title(),
             'handle' => $fieldset->handle(),
@@ -102,7 +104,11 @@ public function update(Request $request, $fieldset)
             'fields' => collect($request->fields)->map(function ($field) {
                 return FieldTransformer::fromVue($field);
             })->all(),
-        ]))->save();
+        ]));
+
+        $fieldset->validateRecursion();
+
+        $fieldset->save();
 
         return response('', 204);
     }

src/Http/Controllers/CP/Fields/ManagesBlueprints.php

@@ -6,6 +6,7 @@
 use Illuminate\Support\Collection;
 use Illuminate\Validation\ValidationException;
 use Statamic\Exceptions\DuplicateFieldException;
+use Statamic\Exceptions\FieldsetRecursionException;
 use Statamic\Facades;
 use Statamic\Fields\Blueprint;
 use Statamic\Fields\FieldTransformer;
@@ -49,6 +50,17 @@ private function setBlueprintContents(Request $request, Blueprint $blueprint)
         return $blueprint;
     }
 
+    private function validateRecursion($blueprint)
+    {
+        try {
+            $blueprint->fields();
+        } catch (FieldsetRecursionException $exception) {
+            throw ValidationException::withMessages([
+                'tabs' => __('statamic::validation.fieldset_imported_recursively', ['handle' => $exception->getFieldset()]),
+            ]);
+        }
+    }
+
     private function validateUniqueHandles($blueprint)
     {
         try {
@@ -75,6 +87,8 @@ private function updateBlueprint($request, $blueprint)
     {
         $this->setBlueprintContents($request, $blueprint);
 
+        $this->validateRecursion($blueprint);
+
         $this->validateUniqueHandles($blueprint);
 
         $this->validateReservedFieldHandles($blueprint);

src/Providers/AppServiceProvider.php

@@ -13,6 +13,7 @@
 use Statamic\Facades\Preference;
 use Statamic\Facades\Site;
 use Statamic\Facades\Token;
+use Statamic\Fields\FieldsetRecursionStack;
 use Statamic\Sites\Sites;
 use Statamic\Statamic;
 use Statamic\Tokens\Handlers\LivePreview;
@@ -152,6 +153,8 @@ public function register()
                 ->setDirectory(resource_path('fieldsets'));
         });
 
+        $this->app->singleton(FieldsetRecursionStack::class);
+
         collect([
             'entries' => fn () => Facades\Entry::query(),
             'form-submissions' => fn () => Facades\FormSubmission::query(),

tests/Fields/FieldsTest.php

@@ -6,6 +6,7 @@
 use Facades\Statamic\Fields\FieldtypeRepository;
 use Facades\Statamic\Fields\Validator;
 use Illuminate\Support\Collection;
+use Statamic\Exceptions\FieldsetRecursionException;
 use Statamic\Facades\Fieldset as FieldsetRepository;
 use Statamic\Fields\Field;
 use Statamic\Fields\Fields;
@@ -1057,4 +1058,71 @@ public function it_sets_the_parentfield_and_parentindex_on_referenced_fields()
         $this->assertEquals($parentField, $collection['bar']->parentField());
         $this->assertEquals(1, $collection['bar']->parentIndex());
     }
+
+    /** @test */
+    public function it_does_not_allow_recursive_imports()
+    {
+        $this->expectException(FieldsetRecursionException::class);
+
+        $one = (new Fieldset)->setHandle('one')->setContents([
+            'fields' => [
+                [
+                    'import' => 'two',
+                ],
+            ],
+        ]);
+
+        $two = (new Fieldset)->setHandle('two')->setContents([
+            'fields' => [
+                [
+                    'import' => 'one',
+                ],
+            ],
+        ]);
+
+        FieldsetRepository::shouldReceive('find')->with('one')->zeroOrMoreTimes()->andReturn($one);
+        FieldsetRepository::shouldReceive('find')->with('two')->zeroOrMoreTimes()->andReturn($two);
+
+        new Fields([
+            [
+                'import' => 'one',
+            ],
+        ]);
+    }
+
+    /** @test */
+    public function import_recursion_check_should_reset_across_instances()
+    {
+        $one = (new Fieldset)->setHandle('one')->setContents([
+            'fields' => [
+                [
+                    'import' => 'two',
+                ],
+            ],
+        ]);
+
+        $two = (new Fieldset)->setHandle('two')->setContents([
+            'fields' => [
+                [
+                    'handle' => 'foo',
+                    'field' => ['type' => 'text'],
+                ],
+            ],
+        ]);
+
+        FieldsetRepository::shouldReceive('find')->with('one')->zeroOrMoreTimes()->andReturn($one);
+        FieldsetRepository::shouldReceive('find')->with('two')->zeroOrMoreTimes()->andReturn($two);
+
+        new Fields([
+            [
+                'import' => 'one',
+            ],
+        ]);
+
+        new Fields([
+            [
+                'import' => 'two',
+            ],
+        ]);
+    }
 }