bug #42114 [HttpFoundation] Fix return types of SessionHandler::gc() (derrabus)

This PR was merged into the 4.4 branch.

Discussion
----------

[HttpFoundation] Fix return types of SessionHandler::gc()

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | #41552
| License       | MIT
| Doc PR        | N/A

`SessionHandler::gc()` should return the number of garbage-collected sessions. We often return `true` which violates that contract.

Commits
-------

1261a4139d [HttpFoundation] Fix return types of SessionHandler::gc()

src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MemcachedSessionHandler.php

@@ -99,12 +99,13 @@ class MemcachedSessionHandler extends AbstractSessionHandler
     }
 
     /**
-     * @return bool
+     * @return int|false
      */
+    #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
     {
         // not required here because memcached will auto expire the records anyhow.
-        return true;
+        return 0;
     }
 
     /**

src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MigratingSessionHandler.php

@@ -63,7 +63,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     }
 
     /**
-     * @return bool
+     * @return int|false
      */
     #[\ReturnTypeWillChange]
     public function gc($maxlifetime)

src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MongoDbSessionHandler.php

@@ -100,15 +100,14 @@ class MongoDbSessionHandler extends AbstractSessionHandler
     }
 
     /**
-     * @return bool
+     * @return int|false
      */
+    #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
     {
-        $this->getCollection()->deleteMany([
+        return $this->getCollection()->deleteMany([
             $this->options['expiry_field'] => ['$lt' => new \MongoDB\BSON\UTCDateTime()],
-        ]);
+        ])->getDeletedCount();
-
-        return true;
     }
 
     /**

src/Symfony/Component/HttpFoundation/Session/Storage/Handler/NullSessionHandler.php

@@ -70,11 +70,11 @@ class NullSessionHandler extends AbstractSessionHandler
     }
 
     /**
-     * @return bool
+     * @return int|false
      */
     #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
     {
-        return true;
+        return 0;
     }
 }

src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php

@@ -290,7 +290,7 @@ class PdoSessionHandler extends AbstractSessionHandler
     }
 
     /**
-     * @return bool
+     * @return int|false
      */
     #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
@@ -299,7 +299,7 @@ class PdoSessionHandler extends AbstractSessionHandler
         // This way, pruning expired sessions does not block them from being started while the current session is used.
         $this->gcCalled = true;
 
-        return true;
+        return 0;
     }
 
     /**

src/Symfony/Component/HttpFoundation/Session/Storage/Handler/RedisSessionHandler.php

@@ -104,10 +104,13 @@ class RedisSessionHandler extends AbstractSessionHandler
 
     /**
      * {@inheritdoc}
+     *
+     * @return int|false
      */
-    public function gc($maxlifetime): bool
+    #[\ReturnTypeWillChange]
+    public function gc($maxlifetime)
     {
-        return true;
+        return 0;
     }
 
     /**

src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/AbstractRedisSessionHandlerTestCase.php

@@ -114,7 +114,7 @@ abstract class AbstractRedisSessionHandlerTestCase extends TestCase
 
     public function testGcSession()
     {
-        $this->assertTrue($this->storage->gc(123));
+        $this->assertIsInt($this->storage->gc(123));
     }
 
     public function testUpdateTimestamp()

src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/Fixtures/common.inc

@@ -121,11 +121,12 @@ class TestSessionHandler extends AbstractSessionHandler
         return true;
     }
 
-    public function gc($maxLifetime): bool
+    #[\ReturnTypeWillChange]
+    public function gc($maxLifetime)
     {
         echo __FUNCTION__, "\n";
 
-        return true;
+        return 1;
     }
 
     protected function doRead($sessionId): string

src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MemcachedSessionHandlerTest.php

@@ -113,7 +113,7 @@ class MemcachedSessionHandlerTest extends TestCase
 
     public function testGcSession()
     {
-        $this->assertTrue($this->storage->gc(123));
+        $this->assertIsInt($this->storage->gc(123));
     }
 
     /**

src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MongoDbSessionHandlerTest.php

@@ -184,9 +184,14 @@ class MongoDbSessionHandlerTest extends TestCase
             ->willReturnCallback(function ($criteria) {
                 $this->assertInstanceOf(\MongoDB\BSON\UTCDateTime::class, $criteria[$this->options['expiry_field']]['$lt']);
                 $this->assertGreaterThanOrEqual(time() - 1, round((string) $criteria[$this->options['expiry_field']]['$lt'] / 1000));
+
+                $result = $this->createMock(\MongoDB\DeleteResult::class);
+                $result->method('getDeletedCount')->willReturn(42);
+
+                return $result;
             });
 
-        $this->assertTrue($this->storage->gc(1));
+        $this->assertSame(42, $this->storage->gc(1));
     }
 
     public function testGetConnection()