Simplify ColumnsTrait::fieldAlias

src/Select/Traits/ColumnsTrait.php

@@ -27,13 +27,11 @@ trait ColumnsTrait
     public function fieldAlias(string $field): ?string
     {
         // The field can be a JSON path separated by ->
-        if (\str_contains($field, '->')) {
-            $parts = \explode('->', $field, 2);
+        $p = \explode('->', $field, 2);
 
-            return isset($this->columns[$parts[0]]) ? \sprintf('%s->%s', $this->columns[$parts[0]], $parts[1]) : null;
-        }
+        $p[0] = $this->columns[$p[0]] ?? null;
 
-        return $this->columns[$field] ?? null;
+        return $p[0] === null ? null : \implode('->', $p);
     }
 
     /**

tests/ORM/Unit/Select/Traits/ColumnsTrait.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Unit\Select\Traits;
+
+use PHPUnit\Framework\TestCase;
+
+final class ColumnsTrait extends TestCase
+{
+    private const FIELDS = ['id' => 'column_id'];
+
+    public static function getColumnsDataProvider(): iterable
+    {
+        yield ['id', 'column_id'];
+        yield ['name', null];
+        yield ['id->foo', 'column_id->foo'];
+        yield ['name->foo', null];
+        yield ['->foo', null];
+        yield ['', null];
+    }
+
+    /**
+     * @dataProvider getColumnsDataProvider
+     */
+    public function testGetColumns(string $input, ?string $expected): void
+    {
+        $class = $this->prepareClass();
+
+        for ($i = 10000; $i > 0; --$i) {
+            $class->fieldAlias($input);
+        }
+
+        $this->assertSame($expected, $class->fieldAlias($input));
+    }
+
+    private function prepareClass(): object
+    {
+        return new class(self::FIELDS) {
+            use \Cycle\ORM\Select\Traits\ColumnsTrait
+            {
+                fieldAlias as public;
+            }
+
+            public function __construct(array $columns)
+            {
+                $this->columns = $columns;
+            }
+
+            public function getAlias(): string
+            {
+                return 'test';
+            }
+        };
+    }
+}