fix: release pending pool connections on error (#632)

* release pending pool connections on error

* changeset

* simplify try/catch

* oops - remove package-lock.json

---------

Co-authored-by: Michael Nigh <[email protected]>
Co-authored-by: Gajus Kuizinas <[email protected]>

.changeset/metal-clocks-guess.md

@@ -0,0 +1,5 @@
+---
+"slonik": patch
+---
+
+Fix: release pending pool connections on error

packages/slonik/src/factories/createConnectionPool.ts

@@ -139,7 +139,10 @@ export const createConnectionPool = ({
 
       pendingConnections.push(pendingConnection);
 
-      const connection = await pendingConnection;
+      const connection = await pendingConnection.catch((error) => {
+        pendingConnections.pop();
+        throw error;
+      });
 
       const onRelease = () => {
         const waitingClient = waitingClients.shift();

packages/slonik/src/integration.test/lost-connection.test.ts

@@ -0,0 +1,50 @@
+/* eslint-disable no-console */
+
+import { createPool, sql } from '..';
+import { startTestContainer } from './termination.test';
+import test from 'ava';
+import { execSync } from 'node:child_process';
+
+/**
+ * @see https://github.com/gajus/slonik/issues/631
+ */
+test('releases failed connections', async (t) => {
+  t.timeout(10_000);
+
+  try {
+    const output = execSync('docker --version', { encoding: 'utf8' });
+    console.log('Docker CLI is available:', output.trim());
+  } catch {
+    console.log('Skipper the test. Docker CLI is not available.');
+
+    return;
+  }
+
+  const { dsn, terminate } = await startTestContainer();
+
+  const pool = await createPool(dsn, {
+    connectionRetryLimit: 1,
+    connectionTimeout: 500,
+    maximumPoolSize: 1,
+  });
+
+  terminate();
+
+  const isConnectionAvailable = async () => {
+    try {
+      await pool.connect((connection) => {
+        return connection.oneFirst(sql.unsafe`SELECT NOW()`);
+      });
+      return true;
+    } catch {
+      // do nothing
+    }
+
+    return false;
+  };
+
+  t.deepEqual(
+    [await isConnectionAvailable(), await isConnectionAvailable()],
+    [false, false],
+  );
+});

packages/slonik/src/integration.test/termination.test.ts

@@ -7,7 +7,7 @@ import { execSync, spawn } from 'node:child_process';
 import { randomUUID } from 'node:crypto';
 import { setTimeout } from 'node:timers/promises';
 
-const startTestContainer = async () => {
+export const startTestContainer = async () => {
   const dockerContainerName = `slonik-test-${randomUUID()}`;
   const servicePort = await getPort();