Fix warnings on complex keys

Fix warnings being emitted when complex data types are used for primary
key values.

Fixes #12920

src/ORM/Table.php

@@ -2086,7 +2086,9 @@ class Table implements RepositoryInterface, EventListenerInterface, EventDispatc
         $primary = array_combine($primary, $id);
         $primary = array_intersect_key($data, $primary) + $primary;
 
-        $filteredKeys = array_filter($primary, 'strlen');
+        $filteredKeys = array_filter($primary, function ($v) {
+            return $v !== null;
+        });
         $data += $filteredKeys;
 
         if (count($primary) > 1) {

tests/Fixture/DateKeysFixture.php

@@ -0,0 +1,42 @@
+<?php
+/**
+ * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ * @link          https://cakephp.org CakePHP(tm) Project
+ * @since         3.7.4
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Test\Fixture;
+
+use Cake\TestSuite\Fixture\TestFixture;
+
+/**
+ * Fixture for testing complex types as primary keys
+ */
+class DateKeysFixture extends TestFixture
+{
+
+    /**
+     * fields property
+     *
+     * @var array
+     */
+    public $fields = [
+        'id' => ['type' => 'date'],
+        'title' => ['type' => 'string', 'null' => true],
+        '_constraints' => ['primary' => ['type' => 'primary', 'columns' => ['id']]]
+    ];
+
+    /**
+     * records property
+     *
+     * @var array
+     */
+    public $records = [];
+}

tests/TestCase/ORM/TableComplexIdTest.php

@@ -0,0 +1,120 @@
+<?php
+/**
+ * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ * @link          https://cakephp.org CakePHP(tm) Project
+ * @since         3.7.4
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Test\TestCase\ORM;
+
+use Cake\Datasource\ConnectionManager;
+use Cake\ORM\Entity;
+use Cake\TestSuite\TestCase;
+use Cake\Utility\Text;
+use DateTime;
+
+/**
+ * Integration tests for Table class with uuid primary keys.
+ */
+class TableComplexIdTest extends TestCase
+{
+    /**
+     * Fixtures
+     *
+     * @var array
+     */
+    public $fixtures = [
+        'core.DateKeys',
+    ];
+
+    /**
+     * setup
+     *
+     * @return void
+     */
+    public function setUp()
+    {
+        parent::setUp();
+        $this->connection = ConnectionManager::get('test');
+        static::setAppNamespace();
+    }
+
+    /**
+     * teardown
+     *
+     * @return void
+     */
+    public function tearDown()
+    {
+        parent::tearDown();
+        $this->getTableLocator()->clear();
+    }
+
+    /**
+     * Test saving new records sets uuids
+     *
+     * @return void
+     */
+    public function testSaveNew()
+    {
+        $now = new DateTime('now');
+        $entity = new Entity([
+            'id' => $now,
+            'title' => 'shiny new',
+        ]);
+        $table = $this->getTableLocator()->get('DateKeys');
+        $this->assertSame($entity, $table->save($entity));
+        $this->assertEquals($now, $entity->id);
+
+        $row = $table->find('all')->where(['id' => $entity->id])->first();
+        $this->assertEquals($row->id->format('Y-m-d'), $entity->id->format('Y-m-d'));
+    }
+
+    /**
+     * Test saving existing records works
+     *
+     * @return void
+     */
+    public function testSaveUpdate()
+    {
+        $id = new DateTime('now');
+        $entity = new Entity([
+            'id' => $id,
+            'title' => 'shiny update',
+        ]);
+
+        $table = $this->getTableLocator()->get('DateKeys');
+        $this->assertSame($entity, $table->save($entity));
+        $this->assertEquals($id, $entity->id, 'Should match');
+
+        $row = $table->find('all')->where(['id' => $entity->id])->first();
+        $row->title = 'things';
+        $this->assertSame($row, $table->save($row));
+    }
+
+    /**
+     * Test delete with string pk.
+     *
+     * @return void
+     */
+    public function testDelete()
+    {
+        $table = $this->getTableLocator()->get('DateKeys');
+        $entity = new Entity([
+            'id' => new DateTime('now'),
+            'title' => 'shiny update',
+        ]);
+        $table->save($entity);
+        $this->assertTrue($table->delete($entity));
+
+        $query = $table->find('all')->where(['id' => $entity->id]);
+        $this->assertEmpty($query->first(), 'No row left');
+    }
+}