Invalidate old query cache format (#6510)

|      Q       |   A
|------------- | -----------
| Type         | improvement
| Fixed issues | Follows #6504

#### Summary

I'm changing the query cache format once again: Instead of storing a
tuple of arrays, I'm now storing the whole `ArrayResult` object. This
way, we can easily detect if we support the data returned from the cache
and we can handle future cache format changes in the `__unserialize()`
methods.

After #6504, we would run into errors if an app would attempt to us a
cache written with DBAL 4.1. With my change, the old cache is ignored
and the app would behave as if it had encountered a cache miss instead.

I've also added tests covering the serialization of `ArrayResult`
objects.

src/Cache/ArrayResult.php

@@ -9,6 +9,9 @@
 use Doctrine\DBAL\Exception\InvalidColumnIndex;
 
 use function array_combine;
+use function array_keys;
+use function array_map;
+use function array_values;
 use function count;
 
 /** @internal The class is internal to the caching layer implementation. */
@@ -21,8 +24,10 @@ final class ArrayResult implements Result
  * @param list<list<mixed>> $rows The rows of the result. Each row must have the same number of columns
  * as the number of column names.
  */
- public function __construct(private readonly array $columnNames, private array $rows)
- {
+ public function __construct(
+ private readonly array $columnNames,
+ private array $rows,
+ ) {
  }
 
  public function fetchNumeric(): array|false
@@ -96,6 +101,29 @@ public function free(): void
  $this->rows = [];
  }
 
+ /** @return array{list<string>, list<list<mixed>>} */
+ public function __serialize(): array
+ {
+ return [$this->columnNames, $this->rows];
+ }
+
+ /** @param mixed[] $data */
+ public function __unserialize(array $data): void
+ {
+ // Handle objects serialized with DBAL 4.1 and earlier.
+ if (isset($data["\0" . self::class . "\0data"])) {
+ /** @var list<array<string, mixed>> $legacyData */
+ $legacyData = $data["\0" . self::class . "\0data"];
+
+ $this->columnNames = array_keys($legacyData[0] ?? []);
+ $this->rows = array_map(array_values(...), $legacyData);
+
+ return;
+ }
+
+ [$this->columnNames, $this->rows] = $data;
+ }
+
  /** @return list<mixed>|false */
  private function fetch(): array|false
  {

src/Connection.php

@@ -810,10 +810,8 @@ public function executeCacheQuery(string $sql, array $params, array $types, Quer
  $value = [];
  }
 
- if (isset($value[$realKey])) {
- [$columnNames, $rows] = $value[$realKey];
-
- return new Result(new ArrayResult($columnNames, $rows), $this);
+ if (isset($value[$realKey]) && $value[$realKey] instanceof ArrayResult) {
+ return new Result($value[$realKey], $this);
  }
  } else {
  $value = [];
@@ -828,7 +826,7 @@ public function executeCacheQuery(string $sql, array $params, array $types, Quer
 
  $rows = $result->fetchAllNumeric();
 
- $value[$realKey] = [$columnNames, $rows];
+ $value[$realKey] = new ArrayResult($columnNames, $rows);
 
  $item->set($value);
 
@@ -839,7 +837,7 @@ public function executeCacheQuery(string $sql, array $params, array $types, Quer
 
  $resultCache->save($item);
 
- return new Result(new ArrayResult($columnNames, $rows), $this);
+ return new Result($value[$realKey], $this);
  }
 
  /**

tests/Cache/ArrayResultTest.php

@@ -6,9 +6,15 @@
 
 use Doctrine\DBAL\Cache\ArrayResult;
 use Doctrine\DBAL\Exception\InvalidColumnIndex;
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\Attributes\TestWith;
 use PHPUnit\Framework\TestCase;
 
+use function assert;
+use function file_get_contents;
+use function serialize;
+use function unserialize;
+
 class ArrayResultTest extends TestCase
 {
  private ArrayResult $result;
@@ -105,4 +111,64 @@ public function testSameColumnNames(): void
 
  self::assertEquals([1, 2], $result->fetchNumeric());
  }
+
+ public function testSerialize(): void
+ {
+ $result = unserialize(serialize($this->result));
+
+ self::assertSame([
+ [
+ 'username' => 'jwage',
+ 'active' => true,
+ ],
+ [
+ 'username' => 'romanb',
+ 'active' => false,
+ ],
+ ], $result->fetchAllAssociative());
+
+ self::assertSame(2, $result->columnCount());
+ self::assertSame('username', $result->getColumnName(0));
+ }
+
+ public function testRowPointerIsNotSerialized(): void
+ {
+ $this->result->fetchAssociative();
+ $result = unserialize(serialize($this->result));
+
+ self::assertSame([
+ 'username' => 'jwage',
+ 'active' => true,
+ ], $result->fetchAssociative());
+ }
+
+ #[DataProvider('provideSerializedResultFiles')]
+ public function testUnserialize(string $file): void
+ {
+ $serialized = file_get_contents($file);
+ assert($serialized !== false);
+ $result = unserialize($serialized);
+
+ self::assertInstanceOf(ArrayResult::class, $result);
+ self::assertSame([
+ [
+ 'username' => 'jwage',
+ 'active' => true,
+ ],
+ [
+ 'username' => 'romanb',
+ 'active' => false,
+ ],
+ ], $result->fetchAllAssociative());
+
+ self::assertSame(2, $result->columnCount());
+ self::assertSame('username', $result->getColumnName(0));
+ }
+
+ /** @return iterable<string, array{string}> */
+ public static function provideSerializedResultFiles(): iterable
+ {
+ yield '4.1 format' => [__DIR__ . '/Fixtures/array-result-4.1.txt'];
+ yield '4.2 format' => [__DIR__ . '/Fixtures/array-result-4.2.txt'];
+ }
 }

tests/Cache/Fixtures/array-result-4.2.txt

@@ -0,0 +1 @@
+O:31:"Doctrine\DBAL\Cache\ArrayResult":2:{i:0;a:2:{i:0;s:8:"username";i:1;s:6:"active";}i:1;a:2:{i:0;a:2:{i:0;s:5:"jwage";i:1;b:1;}i:1;a:2:{i:0;s:6:"romanb";i:1;b:0;}}}

tests/Connection/CachedQueryTest.php

@@ -47,6 +47,25 @@ public function testCachedQueryWithChangedImplementationIsExecutedTwice(): void
  )->fetchAllAssociative());
  }
 
+ public function testOldCacheFormat(): void
+ {
+ $connection = $this->createConnection(1, ['foo'], [['bar']]);
+ $cache = new ArrayAdapter();
+ $qcp = new QueryCacheProfile(0, __FUNCTION__, $cache);
+
+ [$cacheKey, $realKey] = $qcp->generateCacheKeys('SELECT 1', [], [], []);
+ $cache->save(
+ $cache->getItem($cacheKey)->set([$realKey => [['foo' => 'bar']]]),
+ );
+
+ self::assertSame([['foo' => 'bar']], $connection->executeCacheQuery('SELECT 1', [], [], $qcp)
+ ->fetchAllAssociative());
+ self::assertSame([['foo' => 'bar']], $connection->executeCacheQuery('SELECT 1', [], [], $qcp)
+ ->fetchAllAssociative());
+
+ self::assertCount(1, $cache->getItem(__FUNCTION__)->get());
+ }
+
  /**
  * @param list<string> $columnNames
  * @param list<list<mixed>> $rows
@@ -56,9 +75,7 @@ private function createConnection(int $expectedQueryCount, array $columnNames, a
  $connection = $this->createMock(Driver\Connection::class);
  $connection->expects(self::exactly($expectedQueryCount))
  ->method('query')
- ->willReturnCallback(static function () use ($columnNames, $rows): ArrayResult {
- return new ArrayResult($columnNames, $rows);
- });
+ ->willReturnCallback(static fn (): ArrayResult => new ArrayResult($columnNames, $rows));
 
  $driver = $this->createMock(Driver::class);
  $driver->method('connect')