ext/pdo_pgsql: Fixed PDO::CURSOR_SCROLL statements closing a cursor that does not exist

[KentarouTakeda]

The destructor of a statement created with [PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL] tries to close the cursor even when it does not exist. This fixes that.

The attempted close causes an error on the database server, but the destructor discards its result, so the error cannot be observed by the user. Apart from polluting the server's log, this is mostly harmless, but when it happens inside a transaction, it causes a strange situation where subsequent statements fail for a reason that cannot be observed.

is_prepared was overloaded to also mean "cursor declared" and was never reset, so the cursor state now has its own flag.

[devnexen]

--- /dev/null
+++ b/ext/pdo_pgsql/tests/cursor_scroll_failed_redeclare.phpt
@@ -0,0 +1,37 @@
+--TEST--
+PDO PgSQL PDO::CURSOR_SCROLL sends no CLOSE after a failed re-declare
+--EXTENSIONS--
+pdo_pgsql
+--SKIPIF--
+<?php
+require __DIR__ . '/config.inc';
+require dirname(__DIR__, 2) . '/pdo/tests/pdo_test.inc';
+PDOTest::skip();
+?>
+--FILE--
+<?php
+
+require_once __DIR__ . "/config.inc";
+
+$db = Pdo::connect($config['ENV']['PDOTEST_DSN']);
+
+$stmt = $db->prepare('SELECT CAST(:v AS int)', [PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL]);
+$stmt->execute([':v' => '1']);
+
+try {
+    $stmt->execute([':v' => 'not an int']);
+} catch (PDOException $e) {
+    echo $e::class, ': ', $e->getCode(), PHP_EOL;
+}
+
+$db->beginTransaction();
+unset($stmt);
+
+$db->exec('SELECT 2');
+
+echo 'Done', PHP_EOL;
+
+?>
+--EXPECT--
+PDOException: 22P02
+Done

[KentarouTakeda]

Thanks, your test failed as expected. I've changed the approach. is_prepared and is_cursor_declared now track the two states separately.

[KentarouTakeda]

I had the wrong target branch. This bug is not new, so it needs to go to PHP-8.4.

[devnexen]

Some more tests :)

--TEST--
PDO PgSQL PDO::CURSOR_SCROLL keeps track of a held cursor when the CLOSE before a re-declare fails
--EXTENSIONS--
pdo_pgsql
--SKIPIF--
<?php
require __DIR__ . '/config.inc';
require dirname(__DIR__, 2) . '/pdo/tests/pdo_test.inc';
PDOTest::skip();
?>
--FILE--
<?php

require __DIR__ . '/../../../ext/pdo/tests/pdo_test.inc';
$db = PDOTest::test_factory(__DIR__ . '/common.phpt');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$stmt = $db->prepare('SELECT CAST(:v AS int)', [PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL]);
$stmt->execute([':v' => '1']);

$db->beginTransaction();

try {
    $db->exec('SELECT 1 / 0');
} catch (PDOException $e) {
    echo $e::class, ': ', $e->getCode(), PHP_EOL;
}

try {
    $stmt->execute([':v' => '2']);
} catch (PDOException $e) {
    echo $e::class, ': ', $e->getCode(), PHP_EOL;
}

$db->rollBack();
unset($stmt);

var_dump($db->query("SELECT count(*) FROM pg_cursors WHERE name LIKE 'pdo\_crsr\_%'")->fetchColumn());

?>
--EXPECT--
PDOException: 22012
PDOException: 25P02
string(1) "0"

--TEST--
PDO PgSQL PDO::CURSOR_SCROLL sends no CLOSE for a cursor a rollback already destroyed
--EXTENSIONS--
pdo_pgsql
--SKIPIF--
<?php
require __DIR__ . '/config.inc';
require dirname(__DIR__, 2) . '/pdo/tests/pdo_test.inc';
PDOTest::skip();
?>
--FILE--
<?php

require __DIR__ . '/../../../ext/pdo/tests/pdo_test.inc';
$db = PDOTest::test_factory(__DIR__ . '/common.phpt');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$db->beginTransaction();

$stmt = $db->prepare('SELECT 1', [PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL]);
$stmt->execute();

$db->rollBack();

$db->beginTransaction();
unset($stmt);

$db->exec('SELECT 2');

echo 'Done', PHP_EOL;

?>
--EXPECT--
Done