From fdb329913c6e71f55c88543ed32ef55d0bfde9aa Mon Sep 17 00:00:00 2001
From: Steve Boyd <emteknetnz@gmail.com>
Date: Wed, 22 Nov 2023 14:17:47 +1300
Subject: [PATCH] ENH Throw exception when no react component

---
 src/Forms/Schema/FormSchema.php    | 21 ++++++++++++++
 tests/php/Forms/FormSchemaTest.php | 45 ++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/src/Forms/Schema/FormSchema.php b/src/Forms/Schema/FormSchema.php
index 4f23cf3c4..a6bd1c2a5 100644
--- a/src/Forms/Schema/FormSchema.php
+++ b/src/Forms/Schema/FormSchema.php
@@ -9,6 +9,7 @@ use SilverStripe\Forms\CompositeField;
 use SilverStripe\Forms\Form;
 use SilverStripe\Forms\FormField;
 use SilverStripe\ORM\ValidationResult;
+use LogicException;
 
 /**
  * Represents a {@link Form} as structured data which allows a frontend library to render it.
@@ -112,9 +113,29 @@ class FormSchema
             $schema['fields'][] = $field->getSchemaData();
         }
 
+        // Validate there are react components for all fields
+        // Note 'actions' (FormActions) are always valid because FormAction.schemaComponent has a default value
+        $this->recursivelyValidateSchemaData($schema['fields']);
+
         return $schema;
     }
 
+    private function recursivelyValidateSchemaData(array $schemaData)
+    {
+        foreach ($schemaData as $data) {
+            if (!$data['schemaType'] && !$data['component']) {
+                $name = $data['name'];
+                $message = "Could not find a react component for field \"$name\"."
+                    . "Replace or remove the field instance from the field list,"
+                    . ' or update the field class and set the schemaDataType or schemaComponent property.';
+                throw new LogicException($message);
+            }
+            if (array_key_exists('children', $data)) {
+                $this->recursivelyValidateSchemaData($data['children']);
+            }
+        }
+    }
+
     /**
      * Gets the current state of this form as a nested array.
      *
diff --git a/tests/php/Forms/FormSchemaTest.php b/tests/php/Forms/FormSchemaTest.php
index a23e09bb1..c032f3a53 100644
--- a/tests/php/Forms/FormSchemaTest.php
+++ b/tests/php/Forms/FormSchemaTest.php
@@ -14,6 +14,8 @@ use SilverStripe\Forms\TextField;
 use SilverStripe\Forms\RequiredFields;
 use SilverStripe\Forms\FormAction;
 use SilverStripe\Forms\PopoverField;
+use SilverStripe\Forms\FormField;
+use LogicException;
 
 class FormSchemaTest extends SapphireTest
 {
@@ -39,6 +41,49 @@ class FormSchemaTest extends SapphireTest
         $this->assertEquals($expected, $schema);
     }
 
+    /**
+     * @dataProvider provideGetSchemaException
+     */
+    public function testGetSchemaException(string $field, bool $expectException): void
+    {
+        $fields = [];
+        if ($field === '<HasComponent>') {
+            $fields[] = (new FormField('TestField'))->setSchemaComponent('MyPretendComponent');
+        } elseif ($field === '<HasDataType>') {
+            $fields[] = new class('TestField') extends FormField {
+                protected $schemaDataType = FormField::SCHEMA_DATA_TYPE_CUSTOM;
+            };
+        } elseif ($field === '<None>') {
+            $fields[] = new FormField('TestField');
+        }
+        $form = new Form(null, 'TestForm', new FieldList($fields));
+        $formSchema = new FormSchema($form);
+        if ($expectException) {
+            $this->expectException(LogicException::class);
+        } else {
+            $this->expectNotToPerformAssertions();
+        }
+        $formSchema->getSchema($form);
+    }
+
+    public function provideGetSchemaException(): array
+    {
+        return [
+            [
+                'field' => '<HasComponent>',
+                'expectException' => false,
+            ],
+            [
+                'field' => '<HasDataType>',
+                'expectException' => false,
+            ],
+            [
+                'field' => '<None>',
+                'expectException' => true,
+            ],
+        ];
+    }
+
     public function testGetState()
     {
         $form = new Form(null, 'TestForm', new FieldList(), new FieldList());