[Cache] Enable namespace-based invalidation by prefixing keys with backend-native namespace separators

Author: nicolas-grekas

CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 ---
 
  * Make `HttpClientTestCase` and `TranslatorTest` compatible with PHPUnit 10+
+ * Add `NamespacedPoolInterface` to support namespace-based invalidation
 
 3.5
 ---

Cache/NamespacedPoolInterface.php

@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\Cache;
+
+use Psr\Cache\InvalidArgumentException;
+
+/**
+ * Enables namespace-based invalidation by prefixing keys with backend-native namespace separators.
+ *
+ * Note that calling `withSubNamespace()` MUST NOT mutate the pool, but return a new instance instead.
+ *
+ * When tags are used, they MUST ignore sub-namespaces.
+ *
+ * @author Nicolas Grekas <[email protected]>
+ */
+interface NamespacedPoolInterface
+{
+    /**
+     * @throws InvalidArgumentException If the namespace contains characters found in ItemInterface's RESERVED_CHARACTERS
+     */
+    public function withSubNamespace(string $namespace): static;
+}