Make cache optional

.roave-backward-compatibility-check.xml

@@ -5,5 +5,6 @@
     <baseline>
         <ignored-regex>#\[BC\] SKIPPED: Roave\\BetterReflection\\Reflection\\ReflectionClass "Yiisoft\\Yii\\Debug\\#</ignored-regex>
         <ignored-regex>#\[BC\] SKIPPED: An enum expression Yiisoft\\Db\\QueryBuilder\\Condition\\Like#</ignored-regex>
+        <ignored-regex>#\[BC\] SKIPPED: Unable to compile initializer in class Yiisoft\\Db\\Driver\\Pdo\\AbstractPdoConnection#</ignored-regex>
     </baseline>
 </roave-bc-check>

CHANGELOG.md

@@ -12,6 +12,9 @@
 - New #1152: Add `UuidValue` expression that represents a UUID value independently of DBMS (@KalimeroMK)
 - Enh #1152: Improve the exception message of `DbUuidHelper::toUuid()` when the value isn't a valid UUID
   (@KalimeroMK)
+- Enh #1201: Make `$psrCache` parameter of `SchemaCache` constructor and `$schemaCache` parameter of
+  `AbstractSchema` and `AbstractPdoConnection` constructors optional, remove `psr/simple-cache-implementation` from
+  `require` in `composer.json` (@vjik)
 
 ## 2.0.1 February 09, 2026
 

README.md

@@ -45,11 +45,12 @@ To install `yiisoft/db` you must install at least one database driver:
 - [`yiisoft/db-mssql`](https://github.com/yiisoft/db-mssql);
 - [`yiisoft/db-oracle`](https://github.com/yiisoft/db-oracle).
 
-> [!IMPORTANT]
-> It also depends on [PSR-16: Common Interface for Caching Libraries](https://www.php-fig.org/psr/psr-16/) and requires
-> the installation of [PSR-16 implementation](https://packagist.org/providers/psr/simple-cache-implementation).
+> [!TIP]
+> To cache database schema information, install
+> [PSR-16 implementation](https://packagist.org/providers/psr/simple-cache-implementation).
 > For example, [yiisoft/cache](https://github.com/yiisoft/cache) or one of the other
 > [cache handlers](https://github.com/yiisoft/cache#cache-handlers).
+> It's strongly recommended for production.
 
 ## General Usage
 

composer-dependency-analyser.php

@@ -14,7 +14,7 @@
     ->ignoreErrorsOnPackages(['yiisoft/yii-debug'], [ErrorType::DEV_DEPENDENCY_IN_PROD])
     // Virtual packages that are not directly used in the code.
     ->ignoreErrorsOnPackages(
-        ['psr/simple-cache-implementation', 'yiisoft/db-implementation'],
+        ['yiisoft/db-implementation'],
         [ErrorType::UNUSED_DEPENDENCY],
     );
 

composer.json

@@ -34,15 +34,14 @@
         "ext-pdo": "*",
         "psr/log": "^2.0|^3.0",
         "psr/simple-cache": "^2.0|^3.0",
-        "psr/simple-cache-implementation": "*",
         "yiisoft/db-implementation": "1.0.0"
     },
     "require-dev": {
         "bamarni/composer-bin-plugin": "^1.8.3",
         "ext-mbstring": "*",
         "friendsofphp/php-cs-fixer": "^3.89.1",
         "phpunit/phpunit": "^10.5.45",
-        "rector/rector": "^2.0.10",
+        "rector/rector": "^2.6.7",
         "shipmonk/composer-dependency-analyser": "^1.8",
         "spatie/phpunit-watcher": "^1.24",
         "yiisoft/aliases": "^3.0",

docs/guide/en/README.md

@@ -59,10 +59,11 @@ For [SQLite](https://github.com/yiisoft/db-sqlite):
 composer require yiisoft/db-sqlite
 ```
 
-> [!IMPORTANT]
-> It also depends on [PSR-16: Common Interface for Caching Libraries](https://www.php-fig.org/psr/psr-16/) and requires
-> the installation of [PSR-16 implementation](https://packagist.org/providers/psr/simple-cache-implementation).
+> [!TIP]
+> To cache database schema information, install
+> [PSR-16 implementation](https://packagist.org/providers/psr/simple-cache-implementation).
 > For example, [yiisoft/cache](https://github.com/yiisoft/cache) or one of the other [cache handlers](https://github.com/yiisoft/cache#cache-handlers).
+> It's strongly recommended for production.
 
 ## Configure schema cache
 

docs/guide/en/schema/cache.md

@@ -10,6 +10,11 @@ schema information in [SchemaCache](https://github.com/yiisoft/db/blob/master/sr
 When the [Schema](https://github.com/yiisoft/db/blob/master/src/Schema/AbstractSchema.php) needs
 retrieve information about the database schema, it first checks the cache.
 
+> [!TIP]
+> Configuring schema cache with a real [PSR-16 cache implementation](https://packagist.org/providers/psr/simple-cache-implementation)
+> is strongly recommended for production. Without it, schema information is retrieved from the database server on
+> every request.
+
 You can configure [SchemaCache](https://github.com/yiisoft/db/blob/master/src/Cache/SchemaCache.php) to use
 [PSR-16 cache implementation](https://github.com/php-fig/simple-cache) in two ways:
 
@@ -41,7 +46,8 @@ return [
 ];
 ```
 
-The `SchemaCache` requires `CacheInterface` and DI container will automatically resolve it.
+The `SchemaCache` accepts `CacheInterface` and DI container will automatically resolve it. If `CacheInterface` isn't
+configured, `SchemaCache` uses a cache that doesn't store anything, so schema information isn't cached.
 
 ## Manual cache configuration
 

src/Cache/NullCache.php

@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Db\Cache;
+
+use DateInterval;
+use Psr\SimpleCache\CacheInterface;
+use Traversable;
+
+/**
+ * PSR-16 cache implementation that doesn't store anything.
+ *
+ * {@see SchemaCache} uses it when no cache implementation is provided.
+ *
+ * @internal
+ */
+final class NullCache implements CacheInterface
+{
+    public function get(string $key, mixed $default = null): mixed
+    {
+        return $default;
+    }
+
+    public function set(string $key, mixed $value, int|DateInterval|null $ttl = null): bool
+    {
+        return true;
+    }
+
+    public function delete(string $key): bool
+    {
+        return true;
+    }
+
+    public function clear(): bool
+    {
+        return true;
+    }
+
+    public function getMultiple(iterable $keys, mixed $default = null): iterable
+    {
+        return array_fill_keys(
+            $keys instanceof Traversable ? iterator_to_array($keys) : $keys,
+            $default,
+        );
+    }
+
+    public function setMultiple(iterable $values, int|DateInterval|null $ttl = null): bool
+    {
+        return true;
+    }
+
+    public function deleteMultiple(iterable $keys): bool
+    {
+        return true;
+    }
+
+    public function has(string $key): bool
+    {
+        return false;
+    }
+}

src/Cache/SchemaCache.php

@@ -33,18 +33,21 @@
  */
 final class SchemaCache
 {
+    private readonly CacheInterface $psrCache;
     private int|DateInterval|null $duration = 3600;
     private bool $enabled = true;
     private array $exclude = [];
 
     /**
-     * @param CacheInterface $psrCache PSR-16 cache implementation to use.
+     * @param CacheInterface|null $psrCache PSR-16 cache implementation to use. If `null`, a cache that doesn't store
+     * anything is used.
      *
      * @link https://www.php-fig.org/psr/psr-16/
      */
-    public function __construct(
-        private readonly CacheInterface $psrCache,
-    ) {}
+    public function __construct(?CacheInterface $psrCache = null)
+    {
+        $this->psrCache = $psrCache ?? new NullCache();
+    }
 
     /**
      * Remove a value with the specified key from cache.

src/Driver/Pdo/AbstractPdoConnection.php

@@ -53,7 +53,7 @@ abstract class AbstractPdoConnection extends AbstractConnection implements PdoCo
 
     public function __construct(
         protected PdoDriverInterface $driver,
-        protected SchemaCache $schemaCache,
+        protected SchemaCache $schemaCache = new SchemaCache(),
         protected ?ColumnFactoryInterface $columnFactory = null,
     ) {}
 

src/Schema/AbstractSchema.php

@@ -55,7 +55,7 @@ abstract class AbstractSchema implements SchemaInterface
 
     public function __construct(
         protected ConnectionInterface $db,
-        private readonly SchemaCache $schemaCache,
+        private readonly SchemaCache $schemaCache = new SchemaCache(),
     ) {}
 
     public function getDefaultSchema(): string

tests/Db/Cache/NullCacheTest.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Db\Tests\Db\Cache;
+
+use PHPUnit\Framework\TestCase;
+use Yiisoft\Db\Cache\NullCache;
+
+/**
+ * @group db
+ */
+final class NullCacheTest extends TestCase
+{
+    public function testBase(): void
+    {
+        $cache = new NullCache();
+
+        $this->assertTrue($cache->set('key', 'value'));
+        $this->assertFalse($cache->has('key'));
+        $this->assertNull($cache->get('key'));
+        $this->assertSame('default', $cache->get('key', 'default'));
+        $this->assertTrue($cache->delete('key'));
+        $this->assertTrue($cache->clear());
+    }
+
+    public function testMultiple(): void
+    {
+        $cache = new NullCache();
+
+        $this->assertTrue($cache->setMultiple(['a' => 1, 'b' => 2]));
+        $this->assertSame(['a' => 'default', 'b' => 'default'], $cache->getMultiple(['a', 'b'], 'default'));
+        $this->assertTrue($cache->deleteMultiple(['a', 'b']));
+    }
+}

tests/Db/Cache/SchemaCacheTest.php

@@ -87,6 +87,15 @@ public function testWithFailSetCache(): void
         $schemaCache->set('key', 'test');
     }
 
+    public function testWithoutPsrCache(): void
+    {
+        $schemaCache = new SchemaCache();
+
+        $schemaCache->set('key', 'value', 'tag');
+
+        $this->assertNull($schemaCache->get('key'));
+    }
+
     public function testInvalidCacheKey(): void
     {
         $resource = fopen('php://memory', 'r');

tests/Db/Driver/Pdo/PdoConnectionTest.php

@@ -5,12 +5,10 @@
 namespace Yiisoft\Db\Tests\Db\Driver\Pdo;
 
 use PHPUnit\Framework\TestCase;
-use Yiisoft\Db\Cache\SchemaCache;
 use Yiisoft\Db\Exception\InvalidCallException;
 use Yiisoft\Db\Exception\InvalidConfigException;
 use Yiisoft\Db\Tests\Support\Stub\StubConnection;
 use Yiisoft\Db\Tests\Support\Stub\StubPdoDriver;
-use Yiisoft\Test\Support\SimpleCache\MemorySimpleCache;
 
 /**
  * @group db
@@ -50,9 +48,6 @@ private function createConnection(string $dsn = 'sqlite::memory:'): StubConnecti
     {
         return new StubConnection(
             new StubPdoDriver($dsn),
-            new SchemaCache(
-                new MemorySimpleCache(),
-            ),
         );
     }
 }

tests/Db/Schema/SchemaTest.php

@@ -4,7 +4,6 @@
 
 namespace Yiisoft\Db\Tests\Db\Schema;
 
-use Yiisoft\Db\Cache\SchemaCache;
 use Yiisoft\Db\Constraint\Check;
 use Yiisoft\Db\Constraint\DefaultValue;
 use Yiisoft\Db\Constraint\ForeignKey;
@@ -17,7 +16,6 @@
 use Yiisoft\Db\Tests\Support\IntegrationTestCase;
 use Yiisoft\Db\Tests\Support\Stub\Schema;
 use Yiisoft\Db\Tests\Support\TestHelper;
-use Yiisoft\Test\Support\SimpleCache\MemorySimpleCache;
 
 use function count;
 
@@ -208,13 +206,9 @@ public function testGetTableSchemas(): void
     {
         $db = $this->getSharedConnection();
 
-        $schemaCache = new SchemaCache(
-            new MemorySimpleCache(),
-        );
-
         $schemaMock = $this->getMockBuilder(Schema::class)
             ->onlyMethods(['findTableNames', 'loadTableSchema'])
-            ->setConstructorArgs([$db, $schemaCache])
+            ->setConstructorArgs([$db])
             ->getMock();
         $schemaMock->expects($this->once())->method('findTableNames')->willReturn(['T_constraints_1']);
         $schemaMock->expects($this->once())->method('loadTableSchema')->willReturn($this->createTableSchemaStub());