From 3a34393634d39681105c738f0c270ab1857ab80a Mon Sep 17 00:00:00 2001
From: brandonkelly <brandon@pixelandtonic.com>
Date: Mon, 2 Dec 2024 15:28:49 -0800
Subject: [PATCH] Fallback to all field layouts for event-defined sources

---
 CHANGELOG.md              |  4 ++++
 src/elements/Asset.php    | 14 +++++++-------
 src/elements/Category.php | 16 ++++++++--------
 src/elements/Entry.php    | 12 ++++++------
 4 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b67ffaefffe..8abb03e3d13 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Release Notes for Craft CMS 4
 
+## Unreleased
+
+- Fixed a bug where asset, category, and entry sources defined by the `EVENT_REGISTER_SOURCES` event didn’t have any custom fields available to them, unless the `EVENT_REGISTER_FIELD_LAYOUTS` event was also used to define the available field layouts for the event-defined source. ([#16256](https://github.com/craftcms/cms/discussions/16256))
+
 ## 4.13.4 - 2024-12-02
 
 - Reduced the likelihood of a deadlock error occurring when updating search indexes. ([#15221](https://github.com/craftcms/cms/issues/15221))
diff --git a/src/elements/Asset.php b/src/elements/Asset.php
index 82c3da92eed..529880cdd83 100644
--- a/src/elements/Asset.php
+++ b/src/elements/Asset.php
@@ -442,14 +442,14 @@ public static function sourcePath(string $sourceKey, string $stepKey, ?string $c
      */
     protected static function defineFieldLayouts(string $source): array
     {
-        $fieldLayouts = [];
-        if (
-            preg_match('/^volume:(.+)$/', $source, $matches) &&
-            ($volume = Craft::$app->getVolumes()->getVolumeByUid($matches[1]))
-        ) {
-            $fieldLayouts[] = $volume->getFieldLayout();
+        if (preg_match('/^volume:(.+)$/', $source, $matches)) {
+            $volume = Craft::$app->getVolumes()->getVolumeByUid($matches[1]);
+            return array_filter([
+                $volume?->getFieldLayout(),
+            ]);
         }
-        return $fieldLayouts;
+
+        return parent::defineFieldLayouts($source);
     }
 
     /**
diff --git a/src/elements/Category.php b/src/elements/Category.php
index 089cee9830b..38863ff785b 100644
--- a/src/elements/Category.php
+++ b/src/elements/Category.php
@@ -212,14 +212,14 @@ protected static function defineSources(string $context): array
      */
     protected static function defineFieldLayouts(string $source): array
     {
-        $fieldLayouts = [];
-        if (
-            preg_match('/^group:(.+)$/', $source, $matches) &&
-            ($group = Craft::$app->getCategories()->getGroupByUid($matches[1]))
-        ) {
-            $fieldLayouts[] = $group->getFieldLayout();
-        }
-        return $fieldLayouts;
+        if (preg_match('/^group:(.+)$/', $source, $matches)) {
+            $group = Craft::$app->getCategories()->getGroupByUid($matches[1]);
+            return array_filter([
+                $group?->getFieldLayout(),
+            ]);
+        }
+
+        return parent::defineFieldLayouts($source);
     }
 
     /**
diff --git a/src/elements/Entry.php b/src/elements/Entry.php
index 84c645f0f8c..938016ab4e6 100644
--- a/src/elements/Entry.php
+++ b/src/elements/Entry.php
@@ -350,16 +350,16 @@ public static function modifyCustomSource(array $config): array
     protected static function defineFieldLayouts(string $source): array
     {
         // Get all the sections covered by this source
-        $sections = [];
         if ($source === '*') {
             $sections = Craft::$app->getSections()->getAllSections();
         } elseif ($source === 'singles') {
             $sections = Craft::$app->getSections()->getSectionsByType(Section::TYPE_SINGLE);
-        } elseif (
-            preg_match('/^section:(.+)$/', $source, $matches) &&
-            $section = Craft::$app->getSections()->getSectionByUid($matches[1])
-        ) {
-            $sections = [$section];
+        } elseif (preg_match('/^section:(.+)$/', $source, $matches)) {
+            $sections = array_filter([
+                Craft::$app->getSections()->getSectionByUid($matches[1]),
+            ]);
+        } else {
+            return parent::defineFieldLayouts($source);
         }
 
         $fieldLayouts = [];