From 77a4c710286ecb89fffa32ad6b3841ee145b8db4 Mon Sep 17 00:00:00 2001
From: Simon Podlipsky <simon@podlipsky.net>
Date: Tue, 23 Jun 2026 09:45:34 +0300
Subject: [PATCH 1/6] test: reproduce transaction release race

---
 test/TransactionReleaseRaceTest.php | 175 ++++++++++++++++++++++++++++
 1 file changed, 175 insertions(+)
 create mode 100644 test/TransactionReleaseRaceTest.php

diff --git a/test/TransactionReleaseRaceTest.php b/test/TransactionReleaseRaceTest.php
new file mode 100644
index 0000000..acf12e1
--- /dev/null
+++ b/test/TransactionReleaseRaceTest.php
@@ -0,0 +1,175 @@
+<?php declare(strict_types=1);
+
+namespace Amp\Postgres\Test;
+
+use Amp\Cancellation;
+use Amp\PHPUnit\AsyncTestCase;
+use Amp\Postgres\Internal\PostgresHandle;
+use Amp\Postgres\Internal\PostgresHandleConnection;
+use Amp\Postgres\PostgresConfig;
+use Amp\Postgres\PostgresConnection;
+use Amp\Postgres\PostgresListener;
+use Amp\Postgres\PostgresResult;
+use Amp\Postgres\PostgresStatement;
+use Amp\Sql\SqlConnectionException;
+use Revolt\EventLoop;
+use function Amp\delay;
+
+final class TransactionReleaseRaceTest extends AsyncTestCase
+{
+    public function testSequentialTransactionsWaitForPreviousRelease(): void
+    {
+        $connection = self::createConnection();
+
+        $transaction = $connection->beginTransaction();
+        $transaction->commit();
+
+        $transaction = $connection->beginTransaction();
+        $transaction->commit();
+
+        delay(0);
+
+        $this->expectNotToPerformAssertions();
+    }
+
+    private static function createConnection(): PostgresConnection
+    {
+        $reflection = new \ReflectionClass(RaceTestConnection::class);
+        $connection = $reflection->newInstanceWithoutConstructor();
+        $reflection->getConstructor()->invoke($connection, new RaceTestHandle());
+
+        return $connection;
+    }
+}
+
+final class RaceTestConnection extends PostgresHandleConnection
+{
+    public static function connect(PostgresConfig $config, ?Cancellation $cancellation = null): self
+    {
+        throw new SqlConnectionException('Not used in this test');
+    }
+}
+
+final class RaceTestHandle implements PostgresHandle
+{
+    public function close(): void
+    {
+    }
+
+    public function commit(): void
+    {
+    }
+
+    public function createSavepoint(string $identifier): void
+    {
+    }
+
+    public function escapeByteA(string $data): string
+    {
+        return $data;
+    }
+
+    public function execute(string $sql, array $params = []): PostgresResult
+    {
+        return new RaceTestResult();
+    }
+
+    public function getConfig(): PostgresConfig
+    {
+        return new PostgresConfig(host: 'localhost');
+    }
+
+    public function getLastUsedAt(): int
+    {
+        return 0;
+    }
+
+    public function isClosed(): bool
+    {
+        return false;
+    }
+
+    public function listen(string $channel): PostgresListener
+    {
+        throw new \BadMethodCallException('Not used in this test');
+    }
+
+    public function notify(string $channel, string $payload = ""): PostgresResult
+    {
+        return new RaceTestResult();
+    }
+
+    public function onClose(\Closure $onClose): void
+    {
+        EventLoop::queue($onClose);
+    }
+
+    public function prepare(string $sql): PostgresStatement
+    {
+        throw new \BadMethodCallException('Not used in this test');
+    }
+
+    public function query(string $sql): PostgresResult
+    {
+        return new RaceTestResult();
+    }
+
+    public function quoteIdentifier(string $name): string
+    {
+        return $name;
+    }
+
+    public function quoteLiteral(string $data): string
+    {
+        return $data;
+    }
+
+    public function releaseSavepoint(string $identifier): void
+    {
+    }
+
+    public function rollback(): void
+    {
+    }
+
+    public function rollbackTo(string $identifier): void
+    {
+    }
+
+    public function statementDeallocate(string $name): void
+    {
+    }
+
+    public function statementExecute(string $name, array $params): PostgresResult
+    {
+        return new RaceTestResult();
+    }
+}
+
+final class RaceTestResult implements PostgresResult, \IteratorAggregate
+{
+    public function fetchRow(): ?array
+    {
+        return null;
+    }
+
+    public function getColumnCount(): ?int
+    {
+        return null;
+    }
+
+    public function getIterator(): \Traversable
+    {
+        return new \EmptyIterator();
+    }
+
+    public function getNextResult(): ?PostgresResult
+    {
+        return null;
+    }
+
+    public function getRowCount(): ?int
+    {
+        return null;
+    }
+}

From f578783c9b330b2ad5f14b8f2ac172e960d1050d Mon Sep 17 00:00:00 2001
From: Simon Podlipsky <simon@podlipsky.net>
Date: Tue, 23 Jun 2026 10:01:19 +0300
Subject: [PATCH 2/6] Wait for transaction release before beginning another
 transaction

---
 src/Internal/PostgresHandleConnection.php | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Internal/PostgresHandleConnection.php b/src/Internal/PostgresHandleConnection.php
index 9a6cc57..1fa5f9f 100644
--- a/src/Internal/PostgresHandleConnection.php
+++ b/src/Internal/PostgresHandleConnection.php
@@ -135,6 +135,7 @@ final public function listen(string $channel): PostgresListener
     #[\Override]
     final public function beginTransaction(): PostgresTransaction
     {
+        $this->awaitPending();
         $this->reserve();
 
         try {

From 0a56e14293e19fa9b3439d7b3c88e7c2694819a4 Mon Sep 17 00:00:00 2001
From: Aaron Piotrowski <aaron@trowski.com>
Date: Mon, 2 Nov 2026 19:27:36 -0600
Subject: [PATCH 3/6] Move awaitPending call into release

---
 src/Internal/PostgresHandleConnection.php | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/Internal/PostgresHandleConnection.php b/src/Internal/PostgresHandleConnection.php
index 1fa5f9f..edbe9e6 100644
--- a/src/Internal/PostgresHandleConnection.php
+++ b/src/Internal/PostgresHandleConnection.php
@@ -82,8 +82,10 @@ private function awaitPending(): void
      */
     private function reserve(): void
     {
+        $this->awaitPending();
         \assert($this->busy === null);
-        $this->busy = new DeferredFuture;
+
+        $this->busy = new DeferredFuture();
     }
 
     /**
@@ -135,7 +137,6 @@ final public function listen(string $channel): PostgresListener
     #[\Override]
     final public function beginTransaction(): PostgresTransaction
     {
-        $this->awaitPending();
         $this->reserve();
 
         try {

From 20685c77d764f39485b71d95fb0eee24fafa8491 Mon Sep 17 00:00:00 2001
From: Aaron Piotrowski <aaron@trowski.com>
Date: Mon, 2 Nov 2026 19:27:52 -0600
Subject: [PATCH 4/6] Move test into AbstractConnectionTest

---
 test/AbstractConnectionTest.php | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/test/AbstractConnectionTest.php b/test/AbstractConnectionTest.php
index b321835..59e57c5 100644
--- a/test/AbstractConnectionTest.php
+++ b/test/AbstractConnectionTest.php
@@ -142,4 +142,17 @@ public function testTransactionsCallbacksOnDestruct(): void
         unset($transaction);
         delay(0.1); // Destructor is async, so give control to the loop to invoke callbacks.
     }
+
+    public function testSequentialTransactionsWaitForPreviousRelease(): void
+    {
+        $connection = $this->executor;
+
+        $transaction = $connection->beginTransaction();
+        $transaction->onClose($this->createCallback(1));
+        $transaction->commit();
+
+        $transaction = $connection->beginTransaction();
+        $transaction->onClose($this->createCallback(1));
+        $transaction->commit();
+    }
 }

From 8777a7c9209a8bd2a077349279b24f270b48564b Mon Sep 17 00:00:00 2001
From: Aaron Piotrowski <aaron@trowski.com>
Date: Mon, 2 Nov 2026 19:37:36 -0600
Subject: [PATCH 5/6] Remove separate test

---
 test/TransactionReleaseRaceTest.php | 175 ----------------------------
 1 file changed, 175 deletions(-)
 delete mode 100644 test/TransactionReleaseRaceTest.php

diff --git a/test/TransactionReleaseRaceTest.php b/test/TransactionReleaseRaceTest.php
deleted file mode 100644
index acf12e1..0000000
--- a/test/TransactionReleaseRaceTest.php
+++ /dev/null
@@ -1,175 +0,0 @@
-<?php declare(strict_types=1);
-
-namespace Amp\Postgres\Test;
-
-use Amp\Cancellation;
-use Amp\PHPUnit\AsyncTestCase;
-use Amp\Postgres\Internal\PostgresHandle;
-use Amp\Postgres\Internal\PostgresHandleConnection;
-use Amp\Postgres\PostgresConfig;
-use Amp\Postgres\PostgresConnection;
-use Amp\Postgres\PostgresListener;
-use Amp\Postgres\PostgresResult;
-use Amp\Postgres\PostgresStatement;
-use Amp\Sql\SqlConnectionException;
-use Revolt\EventLoop;
-use function Amp\delay;
-
-final class TransactionReleaseRaceTest extends AsyncTestCase
-{
-    public function testSequentialTransactionsWaitForPreviousRelease(): void
-    {
-        $connection = self::createConnection();
-
-        $transaction = $connection->beginTransaction();
-        $transaction->commit();
-
-        $transaction = $connection->beginTransaction();
-        $transaction->commit();
-
-        delay(0);
-
-        $this->expectNotToPerformAssertions();
-    }
-
-    private static function createConnection(): PostgresConnection
-    {
-        $reflection = new \ReflectionClass(RaceTestConnection::class);
-        $connection = $reflection->newInstanceWithoutConstructor();
-        $reflection->getConstructor()->invoke($connection, new RaceTestHandle());
-
-        return $connection;
-    }
-}
-
-final class RaceTestConnection extends PostgresHandleConnection
-{
-    public static function connect(PostgresConfig $config, ?Cancellation $cancellation = null): self
-    {
-        throw new SqlConnectionException('Not used in this test');
-    }
-}
-
-final class RaceTestHandle implements PostgresHandle
-{
-    public function close(): void
-    {
-    }
-
-    public function commit(): void
-    {
-    }
-
-    public function createSavepoint(string $identifier): void
-    {
-    }
-
-    public function escapeByteA(string $data): string
-    {
-        return $data;
-    }
-
-    public function execute(string $sql, array $params = []): PostgresResult
-    {
-        return new RaceTestResult();
-    }
-
-    public function getConfig(): PostgresConfig
-    {
-        return new PostgresConfig(host: 'localhost');
-    }
-
-    public function getLastUsedAt(): int
-    {
-        return 0;
-    }
-
-    public function isClosed(): bool
-    {
-        return false;
-    }
-
-    public function listen(string $channel): PostgresListener
-    {
-        throw new \BadMethodCallException('Not used in this test');
-    }
-
-    public function notify(string $channel, string $payload = ""): PostgresResult
-    {
-        return new RaceTestResult();
-    }
-
-    public function onClose(\Closure $onClose): void
-    {
-        EventLoop::queue($onClose);
-    }
-
-    public function prepare(string $sql): PostgresStatement
-    {
-        throw new \BadMethodCallException('Not used in this test');
-    }
-
-    public function query(string $sql): PostgresResult
-    {
-        return new RaceTestResult();
-    }
-
-    public function quoteIdentifier(string $name): string
-    {
-        return $name;
-    }
-
-    public function quoteLiteral(string $data): string
-    {
-        return $data;
-    }
-
-    public function releaseSavepoint(string $identifier): void
-    {
-    }
-
-    public function rollback(): void
-    {
-    }
-
-    public function rollbackTo(string $identifier): void
-    {
-    }
-
-    public function statementDeallocate(string $name): void
-    {
-    }
-
-    public function statementExecute(string $name, array $params): PostgresResult
-    {
-        return new RaceTestResult();
-    }
-}
-
-final class RaceTestResult implements PostgresResult, \IteratorAggregate
-{
-    public function fetchRow(): ?array
-    {
-        return null;
-    }
-
-    public function getColumnCount(): ?int
-    {
-        return null;
-    }
-
-    public function getIterator(): \Traversable
-    {
-        return new \EmptyIterator();
-    }
-
-    public function getNextResult(): ?PostgresResult
-    {
-        return null;
-    }
-
-    public function getRowCount(): ?int
-    {
-        return null;
-    }
-}

From c7d2cb53249ae8468645bed7ca71249fa5d9a3b7 Mon Sep 17 00:00:00 2001
From: Aaron Piotrowski <aaron@trowski.com>
Date: Mon, 2 Nov 2026 19:37:46 -0600
Subject: [PATCH 6/6] Add link to PR on test

---
 test/AbstractConnectionTest.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/test/AbstractConnectionTest.php b/test/AbstractConnectionTest.php
index 59e57c5..67dd6aa 100644
--- a/test/AbstractConnectionTest.php
+++ b/test/AbstractConnectionTest.php
@@ -143,6 +143,10 @@ public function testTransactionsCallbacksOnDestruct(): void
         delay(0.1); // Destructor is async, so give control to the loop to invoke callbacks.
     }
 
+    /**
+     * Ensure prior transaction has fully completed before attempting to begin another transaction.
+     * @see https://github.com/amphp/postgres/pull/73
+     */
     public function testSequentialTransactionsWaitForPreviousRelease(): void
     {
         $connection = $this->executor;