Fix the order of the palette combiner

core-bundle/src/Resources/contao/drivers/DC_Table.php

@@ -3243,7 +3243,12 @@ public function getPalette()
 					}
 					else
 					{
-						$sValues[] = $trigger;
+						// Use string comparison to allow "0"
+						if ((string) $trigger !== '')
+						{
+							$sValues[] = (string) $trigger;
+						}
+
 						$key = $name . '_' . $trigger;
 
 						// Look for a subpalette

core-bundle/tests/Contao/DataContainerTest.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of Contao.
+ *
+ * (c) Leo Feyer
+ *
+ * @license LGPL-3.0-or-later
+ */
+
+namespace Contao\CoreBundle\Tests\Contao;
+
+use Contao\CoreBundle\Tests\TestCase;
+use Contao\DC_Table;
+
+class DataContainerTest extends TestCase
+{
+    /**
+     * @dataProvider getCombinerValues
+     */
+    public function testCombiner(array $source, array $expected): void
+    {
+        $class = new \ReflectionClass(DC_Table::class);
+
+        $method = $class->getMethod('combiner');
+        $method->setAccessible(true);
+
+        $names = $method->invoke($class->newInstanceWithoutConstructor(), $source);
+
+        $this->assertSame($expected, array_values($names));
+    }
+
+    public function getCombinerValues(): array
+    {
+        return [
+            [
+                ['foo'],
+                ['foo'],
+            ],
+            [
+                ['foo', 'bar'],
+                ['bar', 'foobar', 'foo'],
+            ],
+            [
+                ['foo', 'bar', 'baz'],
+                ['baz', 'barbaz', 'bar', 'foobar', 'foobarbaz', 'foobaz', 'foo'],
+            ],
+            [
+                ['foo', 0, 'bar'],
+                ['bar', '0bar', 'foo0', 'foo0bar', 'foobar', 'foo'],
+            ],
+        ];
+    }
+}

core-bundle/tests/Contao/DcTableTest.php

@@ -0,0 +1,87 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of Contao.
+ *
+ * (c) Leo Feyer
+ *
+ * @license LGPL-3.0-or-later
+ */
+
+namespace Contao\CoreBundle\Tests\Contao;
+
+use Contao\CoreBundle\Tests\TestCase;
+use Contao\Database;
+use Contao\Database\Result;
+use Contao\Database\Statement;
+use Contao\DC_Table;
+
+class DcTableTest extends TestCase
+{
+    /**
+     * @dataProvider getPalette
+     */
+    public function testGetPalette(array $dca, array $row, string $expected): void
+    {
+        $result = new Result([$row], '');
+
+        $statement = $this->createMock(Statement::class);
+        $statement
+            ->method('limit')
+            ->willReturn($statement)
+        ;
+
+        $statement
+            ->method('execute')
+            ->willReturn($result)
+        ;
+
+        $database = $this->createMock(Database::class);
+        $database
+            ->method('prepare')
+            ->willReturn($statement)
+        ;
+
+        $reflection = new \ReflectionClass(DC_Table::class);
+        $dataContainer = $reflection->newInstanceWithoutConstructor();
+
+        $method = $reflection->getMethod('import');
+        $method->setAccessible(true);
+        $method->invoke($dataContainer, $database, 'Database');
+
+        $table = $reflection->getProperty('strTable');
+        $table->setAccessible(true);
+        $table->setValue($dataContainer, 'tl_test');
+
+        $GLOBALS['TL_DCA']['tl_test'] = $dca;
+
+        $this->assertSame($expected, $dataContainer->getPalette());
+    }
+
+    public function getPalette(): array
+    {
+        return [[
+            [
+                'palettes' => [
+                    '__selector__' => ['fieldA', 'fieldB', 'fieldC'],
+                    'default' => 'paletteDefault',
+                    'valueA' => 'paletteA',
+                    'valueAvalueC' => 'paletteAC',
+                ],
+                'fields' => [
+                    'fieldA' => ['inputType' => 'text'],
+                    'fieldB' => ['inputType' => 'text'],
+                    'fieldC' => ['inputType' => 'text'],
+                ],
+            ],
+            [
+                'fieldA' => 'valueA',
+                'fieldB' => null,
+                'fieldC' => 'valueC',
+            ],
+            'paletteAC',
+        ]];
+    }
+}