Add support for passing a Twig template to relation condition rules

CHANGELOG-WIP.md

@@ -41,6 +41,7 @@
 - The Asset Indexes utility no longer skips volumes if the root folder was completely empty. ([#12585](https://github.com/craftcms/cms/issues/12585), [#12604](https://github.com/craftcms/cms/pull/12604))
 - The Asset Indexes utility now has a “List empty folders” setting, which determines whether empty folders sholud be listed for deletion from the index. ([#12604](https://github.com/craftcms/cms/pull/12604))
 - The Asset Indexes utility now lists missing/empty folders and files separately in the review screen. ([#12604](https://github.com/craftcms/cms/pull/12604))
+- Relational condition rules for conditions that are saved to the project config now accept a Twig template which outputs a related element ID dynamically. ([#12679](https://github.com/craftcms/cms/pull/12679), [#12676](https://github.com/craftcms/cms/discussions/12676))
 - Improved the CLI output for `index-assets` commands. ([#12604](https://github.com/craftcms/cms/pull/12604))
 
 ### Development
@@ -88,6 +89,7 @@
 - Added `craft\db\QueryBatcher`.
 - Added `craft\debug\DumpPanel`.
 - Added `craft\elements\conditions\assets\ViewableConditionRule`. ([#12266](https://github.com/craftcms/cms/pull/12266))
+- Added `craft\elements\conditions\ElementCondition::$referenceElement`.
 - Added `craft\elements\conditions\entries\ViewableConditionRule`. ([#12266](https://github.com/craftcms/cms/pull/12266))
 - Added `craft\elements\Entry::EVENT_DEFINE_PARENT_SELECTION_CRITERIA`. ([#12475](https://github.com/craftcms/cms/discussions/12475))
 - Added `craft\events\DefineInputOptionsEvent`. ([#12351](https://github.com/craftcms/cms/pull/12351))

src/base/conditions/BaseElementSelectConditionRule.php

@@ -4,9 +4,11 @@
 
 use Craft;
 use craft\base\ElementInterface;
+use craft\elements\conditions\ElementCondition;
 use craft\elements\conditions\ElementConditionInterface;
 use craft\helpers\App;
 use craft\helpers\Cp;
+use stdClass;
 
 /**
  * BaseElementSelectConditionRule provides a base implementation for element query condition rules that are composed of an element select input.
@@ -68,7 +70,13 @@ protected function criteria(): ?array
     public function getElementId(bool $parse = true): int|string|null
     {
         if ($parse && is_string($this->_elementId)) {
-            return App::parseEnv($this->_elementId);
+            $elementId = App::parseEnv($this->_elementId);
+            if ($this->condition instanceof ElementCondition && isset($this->condition->referenceElement)) {
+                $referenceElement = $this->condition->referenceElement;
+            } else {
+                $referenceElement = new stdClass();
+            }
+            return Craft::$app->getView()->renderObjectTemplate($elementId, $referenceElement);
         }
         return $this->_elementId;
     }
@@ -109,6 +117,7 @@ protected function inputHtml(): string
                 'id' => 'elementId',
                 'name' => 'elementId',
                 'value' => $this->getElementId(false),
+                'tip' => Craft::t('app', 'This can be set to an environment variable, or a Twig template that outputs an ID.'),
                 'placeholder' => Craft::t('app', '{type} ID', [
                     'type' => $this->elementType()::displayName(),
                 ]),

src/controllers/AssetsController.php

@@ -11,6 +11,7 @@
 use craft\assetpreviews\Image as ImagePreview;
 use craft\base\Element;
 use craft\elements\Asset;
+use craft\elements\conditions\ElementCondition;
 use craft\errors\AssetException;
 use craft\errors\DeprecationException;
 use craft\errors\ElementNotFoundException;
@@ -262,6 +263,9 @@ public function actionUpload(): Response
             $folderId = $field->resolveDynamicPathToFolderId($element);
 
             $selectionCondition = $field->getSelectionCondition();
+            if ($selectionCondition instanceof ElementCondition) {
+                $selectionCondition->referenceElement = $element;
+            }
         } else {
             $selectionCondition = null;
         }

src/controllers/ElementIndexesController.php

@@ -14,6 +14,7 @@
 use craft\base\ElementInterface;
 use craft\elements\actions\DeleteActionInterface;
 use craft\elements\actions\Restore;
+use craft\elements\conditions\ElementCondition;
 use craft\elements\conditions\ElementConditionInterface;
 use craft\elements\conditions\ElementConditionRuleInterface;
 use craft\elements\db\ElementQueryInterface;
@@ -492,7 +493,17 @@ protected function condition(): ?ElementConditionInterface
             return null;
         }
 
-        return Craft::$app->getConditions()->createCondition($conditionConfig);
+        $condition = Craft::$app->getConditions()->createCondition($conditionConfig);
+
+        if ($condition instanceof ElementCondition) {
+            $referenceElementId = $this->request->getBodyParam('referenceElementId');
+            if ($referenceElementId) {
+                $siteId = $this->request->getBodyParam('referenceElementSiteId');
+                $condition->referenceElement = Craft::$app->getElements()->getElementById((int)$referenceElementId, siteId: $siteId);
+            }
+        }
+
+        return $condition;
     }
 
     /**

src/elements/conditions/ElementCondition.php

@@ -46,6 +46,13 @@ class ElementCondition extends BaseCondition implements ElementConditionInterfac
      */
     public array $queryParams = [];
 
+    /**
+     * @var ElementInterface|null The element that this condition is being executed in reference to, if any.
+     *
+     * @since 4.4.0
+     */
+    public ?ElementInterface $referenceElement = null;
+
     /**
      * Constructor.
      *

src/fields/BaseRelationField.php

@@ -18,6 +18,7 @@
 use craft\db\Query;
 use craft\db\QueryAbortedException;
 use craft\db\Table as DbTable;
+use craft\elements\conditions\ElementCondition;
 use craft\elements\conditions\ElementConditionInterface;
 use craft\elements\db\ElementQuery;
 use craft\elements\db\ElementQueryInterface;
@@ -1194,6 +1195,11 @@ protected function inputTemplateVariables(array|ElementQueryInterface $value = n
             }
         }
 
+        $selectionCondition = $this->getSelectionCondition();
+        if ($selectionCondition instanceof ElementCondition) {
+            $selectionCondition->referenceElement = $element;
+        }
+
         return [
             'jsClass' => $this->inputJsClass,
             'elementType' => static::elementType(),
@@ -1204,7 +1210,8 @@ protected function inputTemplateVariables(array|ElementQueryInterface $value = n
             'name' => $this->handle,
             'elements' => $value,
             'sources' => $this->getInputSources($element),
-            'condition' => $this->getSelectionCondition(),
+            'condition' => $selectionCondition,
+            'referenceElement' => $element,
             'criteria' => $selectionCriteria,
             'showSiteMenu' => ($this->targetSiteId || !$this->showSiteMenu) ? false : 'auto',
             'allowSelfRelations' => (bool)$this->allowSelfRelations,

src/templates/_components/fieldtypes/Assets/input.twig

@@ -51,6 +51,8 @@
     elementType: elementType,
     sources: sources,
     condition: condition ? condition.getConfig() : null,
+    referenceElementId: referenceElement.id ?? null,
+    referenceElementSiteId: referenceElement.siteId ?? null,
     criteria: criteria,
     sourceElementId: sourceElementId,
     viewMode: viewMode,

src/templates/_includes/forms/elementSelect.twig

@@ -64,6 +64,8 @@
         elementType: elementType,
         sources: sources,
         condition: condition ? condition.getConfig() : null,
+        referenceElementId: referenceElement.id ?? null,
+        referenceElementSiteId: referenceElement.siteId ?? null,
         criteria: criteria,
         allowSelfRelations: allowSelfRelations ?? false,
         maintainHierarchy: maintainHierarchy,

src/translations/en/app.php

@@ -1524,6 +1524,7 @@
     'This can be set to an environment variable matching one of the option values.' => 'This can be set to an environment variable matching one of the option values.',
     'This can be set to an environment variable with a boolean value ({examples}).' => 'This can be set to an environment variable with a boolean value ({examples}).',
     'This can be set to an environment variable with a value of a [supported time zone]({url}).' => 'This can be set to an environment variable with a value of a [supported time zone]({url}).',
+    'This can be set to an environment variable, or a Twig template that outputs an ID.' => 'This can be set to an environment variable, or a Twig template that outputs an ID.',
     'This can be set to an environment variable, or begin with an alias.' => 'This can be set to an environment variable, or begin with an alias.',
     'This can be set to an environment variable.' => 'This can be set to an environment variable.',
     'This element is conditional' => 'This element is conditional',

src/web/assets/cp/src/js/BaseElementIndex.js

@@ -1220,6 +1220,8 @@ Craft.BaseElementIndex = Garnish.Base.extend(
         elementType: this.elementType,
         source: this.instanceState.selectedSource,
         condition: this.settings.condition,
+        referenceElementId: this.settings.referenceElementId,
+        referenceElementSiteId: this.settings.referenceElementSiteId,
         criteria: criteria,
         disabledElementIds: this.settings.disabledElementIds,
         viewState: $.extend({}, this.getSelectedSourceState()),
@@ -3086,6 +3088,8 @@ Craft.BaseElementIndex = Garnish.Base.extend(
       modal: null,
       storageKey: null,
       condition: null,
+      referenceElementId: null,
+      referenceElementSiteId: null,
       criteria: null,
       batchSize: 100,
       disabledElementIds: [],

src/web/assets/cp/src/js/BaseElementSelectInput.js

@@ -488,6 +488,8 @@ Craft.BaseElementSelectInput = Garnish.Base.extend(
           storageKey: this.modalStorageKey,
           sources: this.settings.sources,
           condition: this.settings.condition,
+          referenceElementId: this.settings.referenceElementId,
+          referenceElementSiteId: this.settings.referenceElementSiteId,
           criteria: this.settings.criteria,
           multiSelect: this.settings.limit != 1,
           hideOnSelect: !this.settings.maintainHierarchy,
@@ -547,6 +549,17 @@ Craft.BaseElementSelectInput = Garnish.Base.extend(
     },
 
     onModalHide: function () {
+      // If the modal has a condition and a reference element, recreate it each time it’s opened
+      // in case something about the edited element is going to affect the condition
+      if (
+        this.modal &&
+        this.settings.condition &&
+        this.settings.referenceElementId
+      ) {
+        this.modal.destroy();
+        this.modal = null;
+      }
+
       // If can add more elements, do default behavior of focus on "Add" button
       if (this.canAddMoreElements()) return;
 
@@ -775,6 +788,8 @@ Craft.BaseElementSelectInput = Garnish.Base.extend(
       elementType: null,
       sources: null,
       condition: null,
+      referenceElementId: null,
+      referenceElementSiteId: null,
       criteria: {},
       allowSelfRelations: false,
       sourceElementId: null,

src/web/assets/cp/src/js/BaseElementSelectorModal.js

@@ -436,6 +436,8 @@ Craft.BaseElementSelectorModal = Garnish.Modal.extend(
           modal: this,
           storageKey: this.settings.storageKey,
           condition: this.settings.condition,
+          referenceElementId: this.settings.referenceElementId,
+          referenceElementSiteId: this.settings.referenceElementSiteId,
           criteria: this.settings.criteria,
           disabledElementIds: this.settings.disabledElementIds,
           selectable: true,
@@ -460,6 +462,8 @@ Craft.BaseElementSelectorModal = Garnish.Modal.extend(
       storageKey: null,
       sources: null,
       condition: null,
+      referenceElementId: null,
+      referenceElementSiteId: null,
       criteria: null,
       multiSelect: false,
       showSiteMenu: null,