From 337bc5ff4d84e3281b1a8254065fc223fedf40c2 Mon Sep 17 00:00:00 2001
From: Samy Mahmoudi <samy.mahmoudi@gmail.com>
Date: Mon, 19 Jan 2032 18:21:41 -0500
Subject: [PATCH] [HttpFoundation] Fix PdoSessionHandler charset-collation
 mismatch with the Doctrine DBAL

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| License       | MIT

PdoSessionHandler::configureSchema() was setting `utf8mb4_bin` as the collation
without an explicit charset. The Doctrine DBAL may supply a charset from its
configuration hierarchy, producing an invalid combination like
`DEFAULT CHARACTER SET utf8 COLLATE utf8mb4_bin`.

The `utf8mb4_bin` collation is bound to the `utf8mb4` character set: no other
character set produces a valid MySQL statement. While one might aim for
generality and/or optimality by omitting the charset and letting MySQL infer it,
explicitly setting `charset` to `utf8mb4` ensures valid MySQL in all cases.

A new test verifies that both charset and collate options are correctly set for
MySQL.
---
 Session/Storage/Handler/PdoSessionHandler.php    |  1 +
 .../Storage/Handler/PdoSessionHandlerTest.php    | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/Session/Storage/Handler/PdoSessionHandler.php b/Session/Storage/Handler/PdoSessionHandler.php
index 47d412ea368..7ffa3660d19 100644
--- a/Session/Storage/Handler/PdoSessionHandler.php
+++ b/Session/Storage/Handler/PdoSessionHandler.php
@@ -194,6 +194,7 @@ public function configureSchema(Schema $schema, ?\Closure $isSameDatabase = null
                 $table->addColumn($this->dataCol, Types::BLOB)->setNotnull(true);
                 $table->addColumn($this->lifetimeCol, Types::INTEGER)->setUnsigned(true)->setNotnull(true);
                 $table->addColumn($this->timeCol, Types::INTEGER)->setUnsigned(true)->setNotnull(true);
+                $table->addOption('charset', 'utf8mb4');
                 $table->addOption('collate', 'utf8mb4_bin');
                 $table->addOption('engine', 'InnoDB');
                 break;
diff --git a/Tests/Session/Storage/Handler/PdoSessionHandlerTest.php b/Tests/Session/Storage/Handler/PdoSessionHandlerTest.php
index d44fdd17598..cc61855e3d4 100644
--- a/Tests/Session/Storage/Handler/PdoSessionHandlerTest.php
+++ b/Tests/Session/Storage/Handler/PdoSessionHandlerTest.php
@@ -356,6 +356,22 @@ public function testConfigureSchemaTableExistsPdo()
         $this->assertEmpty($table->getColumns(), 'The table was not overwritten');
     }
 
+    public function testConfigureSchemaSetsUtf8mb4CharsetForMysql()
+    {
+        $pdo = new MockPdo('mysql');
+        $pdo->prepareResult = $this->createMock(\PDOStatement::class);
+
+        $schema = new Schema();
+
+        $pdoSessionHandler = new PdoSessionHandler($pdo);
+        $pdoSessionHandler->configureSchema($schema, fn () => true);
+
+        $this->assertTrue($schema->hasTable('sessions'));
+        $table = $schema->getTable('sessions');
+        $this->assertSame('utf8mb4', $table->getOption('charset'));
+        $this->assertSame('utf8mb4_bin', $table->getOption('collate'));
+    }
+
     public static function provideUrlDsnPairs()
     {
         yield ['mysql://localhost/test', 'mysql:host=localhost;dbname=test;'];