bug #28805 Revert "feature #27549 [Cache] Unconditionally use PhpFilesAdapter for system pools" (nicolas-grekas)

This PR was merged into the 4.2-dev branch.

Discussion
----------

Revert "feature #27549 [Cache] Unconditionally use PhpFilesAdapter for system pools"

This reverts commit d4f5d46b13, reversing
changes made to 7e3b7b0b50.

| Q             | A
| ------------- | ---
| Branch?       | 4.2
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Reading #28800, I've just realized that #27549 breaks using system caches with read-only filesystem.
Using ApcuAdapter makes system caches compatible with read-only filesystems.
Note that this affects only non-warmed up pools, as the warmed-up ones use a faster `PhpArrayAdapter` in front.

Commits
-------

dbc1230735 Revert "feature #27549 [Cache] Unconditionally use PhpFilesAdapter for system pools (nicolas-grekas)"

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php

@@ -1601,6 +1601,7 @@ class FrameworkExtension extends Extension
 
         $version = new Parameter('container.build_id');
         $container->getDefinition('cache.adapter.apcu')->replaceArgument(2, $version);
+        $container->getDefinition('cache.adapter.system')->replaceArgument(2, $version);
         $container->getDefinition('cache.adapter.filesystem')->replaceArgument(2, $config['directory']);
 
         if (isset($config['prefix_seed'])) {

src/Symfony/Bundle/FrameworkBundle/Resources/config/cache.xml

@@ -35,16 +35,15 @@
             <tag name="cache.pool" />
         </service>
 
-        <service id="cache.adapter.system" class="Symfony\Component\Cache\Adapter\PhpFilesAdapter" abstract="true">
+        <service id="cache.adapter.system" class="Symfony\Component\Cache\Adapter\AdapterInterface" abstract="true">
+            <factory class="Symfony\Component\Cache\Adapter\AbstractAdapter" method="createSystemCache" />
             <tag name="cache.pool" clearer="cache.system_clearer" />
             <tag name="monolog.logger" channel="cache" />
             <argument /> <!-- namespace -->
             <argument>0</argument> <!-- default lifetime -->
+            <argument /> <!-- version -->
             <argument>%kernel.cache_dir%/pools</argument>
-            <argument>true</argument>
-            <call method="setLogger">
-                <argument type="service" id="logger" on-invalid="ignore" />
-            </call>
+            <argument type="service" id="logger" on-invalid="ignore" />
         </service>
 
         <service id="cache.adapter.apcu" class="Symfony\Component\Cache\Adapter\ApcuAdapter" abstract="true">

src/Symfony/Component/Cache/Adapter/AbstractAdapter.php

@@ -94,6 +94,10 @@ abstract class AbstractAdapter implements AdapterInterface, CacheInterface, Logg
     }
 
     /**
+     * Returns an ApcuAdapter if supported, a PhpFilesAdapter otherwise.
+     *
+     * Using ApcuAdapter makes system caches compatible with read-only filesystems.
+     *
      * @param string               $namespace
      * @param int                  $defaultLifetime
      * @param string               $version
@@ -101,23 +105,15 @@ abstract class AbstractAdapter implements AdapterInterface, CacheInterface, Logg
      * @param LoggerInterface|null $logger
      *
      * @return AdapterInterface
-     *
-     * @deprecated since Symfony 4.2
      */
     public static function createSystemCache($namespace, $defaultLifetime, $version, $directory, LoggerInterface $logger = null)
     {
-        @trigger_error(sprintf('The "%s()" method is deprecated since Symfony 4.2.', __METHOD__), E_USER_DEPRECATED);
-
         if (null === self::$apcuSupported) {
             self::$apcuSupported = ApcuAdapter::isSupported();
         }
 
-        if (!self::$apcuSupported && null === self::$phpFilesSupported) {
-            self::$phpFilesSupported = PhpFilesAdapter::isSupported();
-        }
-
-        if (self::$phpFilesSupported) {
-            $opcache = new PhpFilesAdapter($namespace, $defaultLifetime, $directory);
+        if (!self::$apcuSupported) {
+            $opcache = new PhpFilesAdapter($namespace, $defaultLifetime, $directory, true);
             if (null !== $logger) {
                 $opcache->setLogger($logger);
             }
@@ -125,14 +121,6 @@ abstract class AbstractAdapter implements AdapterInterface, CacheInterface, Logg
             return $opcache;
         }
 
-        $fs = new FilesystemAdapter($namespace, $defaultLifetime, $directory);
-        if (null !== $logger) {
-            $fs->setLogger($logger);
-        }
-        if (!self::$apcuSupported) {
-            return $fs;
-        }
-
         $apcu = new ApcuAdapter($namespace, (int) $defaultLifetime / 5, $version);
         if ('cli' === \PHP_SAPI && !ini_get('apc.enable_cli')) {
             $apcu->setLogger(new NullLogger());
@@ -140,7 +128,7 @@ abstract class AbstractAdapter implements AdapterInterface, CacheInterface, Logg
             $apcu->setLogger($logger);
         }
 
-        return new ChainAdapter(array($apcu, $fs));
+        return $apcu;
     }
 
     public static function createConnection($dsn, array $options = array())

src/Symfony/Component/Cache/CHANGELOG.md

@@ -12,7 +12,6 @@ CHANGELOG
  * added automatic table creation when using Doctrine DBAL with PDO-based backends
  * throw `LogicException` when `CacheItem::tag()` is called on an item coming from a non tag-aware pool
  * deprecated `CacheItem::getPreviousTags()`, use `CacheItem::getMetadata()` instead
- * deprecated the `AbstractAdapter::createSystemCache()` method
  * deprecated the `AbstractAdapter::unserialize()` and `AbstractCache::unserialize()` methods
  * added `CacheCollectorPass` (originally in `FrameworkBundle`)
  * added `CachePoolClearerPass` (originally in `FrameworkBundle`)