Fix Field to SQL convert when materialized field is available

src/Model/AggregateModel.php

@@ -10,6 +10,7 @@
 use Atk4\Data\Model;
 use Atk4\Data\Persistence;
 use Atk4\Data\Persistence\Sql\Expression;
+use Atk4\Data\Persistence\Sql\MaterializedField;
 use Atk4\Data\Persistence\Sql\Query;
 
 /**
@@ -90,6 +91,11 @@ public function setGroupBy(array $fields, array $aggregateExpressions = [])
 
             $seed['expr'] = $this->table->expr($seed['expr'], $exprArgs);
 
+            // convert base model fields to aliases, they are always already materialized as the base model is SQL inner table
+            foreach ($seed['expr']->args['custom'] as $argK => $argV) {
+                $seed['expr']->args['custom'][$argK] = new MaterializedField($this->table, $argV);
+            }
+
             $this->addExpression($name, $seed);
         }
 
@@ -160,7 +166,7 @@ protected function initQueryGrouping(Query $query): void
             if ($field instanceof Expression) {
                 $expression = $field;
             } else {
-                $expression = $this->table->getField($field)->shortName /* TODO shortName should be used by DSQL automatically when in GROUP BY, HAVING, ... */;
+                $expression = new MaterializedField($this->table, $this->table->getField($field)); /* TODO shortName should be used by DSQL automatically when in GROUP BY, HAVING, ... */;
             }
 
             $query->group($expression);

src/Model/EntityFieldPair.php

@@ -4,6 +4,7 @@
 
 namespace Atk4\Data\Model;
 
+use Atk4\Core\WarnDynamicPropertyTrait;
 use Atk4\Data\Field;
 use Atk4\Data\Model;
 
@@ -13,6 +14,8 @@
  */
 class EntityFieldPair
 {
+    use WarnDynamicPropertyTrait;
+
     /** @var TModel */
     private $entity;
     /** @var string */

src/Persistence/Sql/MaterializedField.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Atk4\Data\Persistence\Sql;
+
+use Atk4\Core\WarnDynamicPropertyTrait;
+use Atk4\Data\Field;
+use Atk4\Data\Model;
+use Atk4\Data\Persistence\Sql\Expression;
+use Atk4\Data\Persistence\Sql\Expressionable;
+
+class MaterializedField implements Expressionable
+{
+    use WarnDynamicPropertyTrait;
+
+    protected Field $field;
+
+    public function __construct(Model $context, Field $field)
+    {
+        $field->getOwner()->assertIsModel($context);
+
+        $this->field = $field;
+    }
+
+    public function getDsqlExpression(Expression $expression): Expression
+    {
+        return $expression->expr('{}', [$this->field->shortName]);
+    }
+}