[6.x] Default values can be computed (#14279)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Jason Varga <jason@pixelfear.com>

Author: 3 people

src/Facades/Field.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Statamic\Facades;
+
+use Illuminate\Support\Facades\Facade;
+use Statamic\Fields\FieldRepository;
+
+/**
+ * @method static \Statamic\Fields\Field|null find(string $field)
+ * @method static void computedDefault(string $key, \Closure $callback)
+ * @method static mixed resolveComputedDefault(string $key, mixed $payload = null)
+ *
+ * @see FieldRepository
+ */
+class Field extends Facade
+{
+    protected static function getFacadeAccessor()
+    {
+        return FieldRepository::class;
+    }
+}

src/Fields/Field.php

@@ -8,6 +8,7 @@
 use Illuminate\Support\Facades\Lang;
 use Rebing\GraphQL\Support\Field as GqlField;
 use Statamic\Contracts\Forms\Form;
+use Statamic\Facades\Field as FieldFacade;
 use Statamic\Facades\GraphQL;
 use Statamic\Rules\Handle;
 use Statamic\Support\Arr;
@@ -297,9 +298,26 @@ public function value()
 
     public function defaultValue()
     {
+        if ($this->hasComputedDefault()) {
+            return FieldFacade::resolveComputedDefault(Str::chopStart($this->config['default'], 'computed:'));
+        }
+
         return $this->config['default'] ?? $this->fieldtype()->defaultValue();
     }
 
+    public function hasComputedDefault(): bool
+    {
+        if (! isset($this->config['default'])) {
+            return false;
+        }
+
+        if (! is_string($this->config['default'])) {
+            return false;
+        }
+
+        return Str::startsWith($this->config['default'], 'computed:');
+    }
+
     public function validationValue()
     {
         return $this->fieldtype()->validationValue($this->value);

src/Fields/FieldRepository.php

@@ -2,11 +2,13 @@
 
 namespace Statamic\Fields;
 
+use Closure;
 use Statamic\Support\Str;
 
 class FieldRepository
 {
     protected $fieldsets;
+    protected $computedDefaultCallbacks = [];
 
     public function __construct(FieldsetRepository $fieldsets)
     {
@@ -28,4 +30,18 @@ public function find(string $field): ?Field
 
         return $fieldset->field($handle);
     }
+
+    public function computedDefault(string $key, Closure $callback): void
+    {
+        $this->computedDefaultCallbacks[$key] = $callback;
+    }
+
+    public function resolveComputedDefault(string $key, mixed $payload = null): mixed
+    {
+        if (! array_key_exists($key, $this->computedDefaultCallbacks)) {
+            throw new \RuntimeException("No computed default registered for key [{$key}].");
+        }
+
+        return $this->computedDefaultCallbacks[$key]();
+    }
 }

src/Providers/AppServiceProvider.php

@@ -193,6 +193,8 @@ public function register()
                 });
         });
 
+        $this->app->singleton(\Statamic\Fields\FieldRepository::class);
+
         $this->app->singleton(\Statamic\Fields\FieldsetRepository::class, function () {
             return (new \Statamic\Fields\FieldsetRepository)
                 ->setDirectory(config('statamic.system.fieldsets_path'));

tests/Fields/FieldTest.php

@@ -5,6 +5,7 @@
 use Facades\Statamic\Fields\FieldtypeRepository;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\Attributes\Test;
+use Statamic\Facades\Field as Fields;
 use Statamic\Fields\Field;
 use Statamic\Fields\Fieldtype;
 use Statamic\Fields\Value;
@@ -294,6 +295,7 @@ public function converts_to_array_suitable_for_rendering_fields_in_publish_compo
             ->andReturn(new class extends Fieldtype
             {
                 protected $component = 'example';
+
                 protected $configFields = [
                     'a_config_field_with_pre_processing' => ['type' => 'with_processing'],
                     'a_config_field_without_pre_processing' => ['type' => 'without_processing'],
@@ -474,6 +476,31 @@ public function defaultValue()
         $this->assertEquals('fieldtype defined default preprocessed', $field->preProcess()->value());
     }
 
+    #[Test]
+    public function preprocessing_a_field_with_no_value_and_computed_default_value_will_use_the_computed_function()
+    {
+        FieldtypeRepository::shouldReceive('find')
+            ->with('fieldtype')
+            ->andReturn(new class extends Fieldtype
+            {
+                public function preProcess($data)
+                {
+                    return $data.' preprocessed';
+                }
+
+                public function defaultValue()
+                {
+                    return 'fieldtype defined default';
+                }
+            });
+
+        Fields::computedDefault('computed-value', fn () => 'computed defined default');
+
+        $field = (new Field('test', ['default' => 'computed:computed-value', 'type' => 'fieldtype']));
+
+        $this->assertEquals('computed defined default preprocessed', $field->preProcess()->value());
+    }
+
     #[Test]
     public function converting_to_an_array_will_inline_the_handle()
     {