MDL-80345 core_lock: deal with hash collisions in postgres_lock_factory

2024-06-21 13:42:59 +02:00
parent cd781ab1b7
commit f341c774de
2 changed files with 136 additions and 14 deletions
@@ -0,0 +1,87 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace core\lock;
+
+/**
+ * Unit tests for the postgres lock factory.
+ *
+ * @covers \core\lock\postgres_lock_factory
+ * @package core
+ * @copyright 2024 Martin Gauk <[email protected]>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+final class postgres_lock_factory_test extends \advanced_testcase {
+    /**
+     * Set up.
+     */
+    public function setUp(): void {
+        global $DB;
+        parent::setUp();
+        // Skip tests if not using Postgres.
+        if (!($DB instanceof \pgsql_native_moodle_database)) {
+            $this->markTestSkipped('Postgres-only test');
+        }
+    }
+
+    /**
+     * Test locking resources that lead to the same token computed by postgres_lock_factory::get_index_from_key.
+     *
+     * It is known that get_index_from_key computes the same token for the strings 'cron_core_cron' and
+     * 'cron_adhoc_82795762'.
+     */
+    public function test_resources_with_same_hash(): void {
+        $cronlockfactory = new postgres_lock_factory('cron');
+        $lock1 = $cronlockfactory->get_lock('core_cron', 0);
+        $this->assertNotFalse($lock1);
+        $lock2 = $cronlockfactory->get_lock('adhoc_82795762', 0);
+        $this->assertNotFalse($lock2);
+
+        $lock2->release();
+        $lock1->release();
+    }
+
+    /**
+     * Test auto_release() method.
+     *
+     * Check that all locks were released after calling auto_release().
+     */
+    public function test_auto_release(): void {
+        $cronlockfactory = new postgres_lock_factory('test');
+        $lock1 = $cronlockfactory->get_lock('1', 0);
+        $this->assertNotFalse($lock1);
+        $lock2 = $cronlockfactory->get_lock('2', 0);
+        $this->assertNotFalse($lock2);
+
+        // Trying to get the lock again should fail as the lock is already held.
+        $this->assertFalse($cronlockfactory->get_lock('1', 0));
+
+        $cronlockfactory->auto_release();
+
+        // We can now lock the resources again.
+        $lock1again = $cronlockfactory->get_lock('1', 0);
+        $this->assertNotFalse($lock1again);
+        $lock2again = $cronlockfactory->get_lock('2', 0);
+        $this->assertNotFalse($lock2again);
+
+        $lock1again->release();
+        $lock2again->release();
+
+        // Need to explicitly release the locks (although they were already released) to avoid the debug message.
+        $lock1->release();
+        $lock2->release();
+    }
+}