append ->nullable() to nullable relationships - closes #4

src/Tasks/AddRelationshipFields.php

@@ -4,10 +4,13 @@
 
 use Closure;
 use Blueprint\Models\Model;
+use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 
 class AddRelationshipFields
 {
+    use InteractWithRelationships;
+
     const INDENT = '            ';
 
     /** @var Model */
@@ -46,11 +49,17 @@ public function handle(array $data, Closure $next)
 
                 $fields .= self::INDENT . $fieldType . "::make('" . $label . "'";
 
-                if ($label !== $class && $label !== Str::plural($class)) {
+                if ($this->classNameNotGuessable($label, $class)) {
                     $fields .= ", '" . $methodName . "', " . $class . '::class';
                 }
 
-                $fields .= '),' . PHP_EOL;
+                $fields .= ')';
+
+                if ($this->isNullable($reference)) {
+                    $fields .= '->nullable()';
+                }
+
+                $fields .= ',' . PHP_EOL;
             }
 
             $fields .= PHP_EOL;
@@ -74,6 +83,25 @@ private function buildMethodName(string $name, string $type)
             : $name;
     }
 
+    private function classNameNotGuessable($label, $class): bool
+    {
+        return $label !== $class
+            && $label !== Str::plural($class);
+    }
+
+    private function isNullable($relation): bool
+    {
+        $relationColumnName = $this->relationshipIdentifiers($this->model->columns())
+            ->filter(function ($relationReference, $columnName) use ($relation) {
+                return in_array($relationReference, Arr::get($this->model->relationships(), 'belongsTo', []))
+                    && $columnName === $relation;
+            })
+            ->first();
+
+        return !is_null($relationColumnName)
+            && in_array('nullable', $this->model->columns()[$relationColumnName]->modifiers());
+    }
+
     private function fieldType(string $dataType): string
     {
         static $fieldTypes = [

tests/NovaGeneratorTest.php

@@ -120,6 +120,7 @@ public function novaTreeDataProvider()
             ['definitions/with-timezones.bp', 'app/Nova/Comment.php', 'nova/with-timezones.php'],
             ['definitions/relationships.bp', 'app/Nova/Comment.php', 'nova/relationships.php'],
             ['definitions/unconventional.bp', 'app/Nova/Team.php', 'nova/unconventional.php'],
+            ['definitions/nullable-relationships.bp', 'app/Nova/Subscription.php', 'nova/nullable-relationships.php'],
             /*
              * @todo work on this
              */

tests/fixtures/definitions/nullable-relationships.bp

@@ -0,0 +1,4 @@
+models:
+  Subscription:
+    user_id: id nullable
+    item_id: id:product

tests/fixtures/nova/nullable-relationships.php

@@ -0,0 +1,97 @@
+<?php
+
+namespace App\Nova;
+
+use Laravel\Nova\Fields\ID;
+use Illuminate\Http\Request;
+use Laravel\Nova\Fields\DateTime;
+use Laravel\Nova\Fields\BelongsTo;
+
+class Subscription extends Resource
+{
+    /**
+     * The model the resource corresponds to.
+     *
+     * @var string
+     */
+    public static $model = \App\Subscription::class;
+
+    /**
+     * The single value that should be used to represent the resource when being displayed.
+     *
+     * @var string
+     */
+    public static $title = 'id';
+
+    /**
+     * The columns that should be searched.
+     *
+     * @var array
+     */
+    public static $search = [
+        'id',
+    ];
+
+    /**
+     * Get the fields displayed by the resource.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @return array
+     */
+    public function fields(Request $request)
+    {
+        return [
+            ID::make()->sortable(),
+
+            BelongsTo::make('User')->nullable(),
+            BelongsTo::make('Item', 'item', Product::class),
+
+            DateTime::make('Created at'),
+            DateTime::make('Updated at'),
+        ];
+    }
+
+    /**
+     * Get the cards available for the request.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @return array
+     */
+    public function cards(Request $request)
+    {
+        return [];
+    }
+
+    /**
+     * Get the filters available for the resource.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @return array
+     */
+    public function filters(Request $request)
+    {
+        return [];
+    }
+
+    /**
+     * Get the lenses available for the resource.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @return array
+     */
+    public function lenses(Request $request)
+    {
+        return [];
+    }
+
+    /**
+     * Get the actions available for the resource.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @return array
+     */
+    public function actions(Request $request)
+    {
+        return [];
+    }
+}