From d7890e1f258dcce0a55db968913ab595e96b02a5 Mon Sep 17 00:00:00 2001
From: Tim van Dam <timvandamcs@gmail.com>
Date: Sat, 3 Dec 2022 16:11:00 +0100
Subject: [PATCH] fix(sqlite): fix off-by-one in max number of active
 connections (#392)

---
 packages/sqlite/src/sqlite-adapter.ts |  2 +-
 packages/sqlite/tests/sqlite.spec.ts  | 30 ++++++++++++++++++++++++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/packages/sqlite/src/sqlite-adapter.ts b/packages/sqlite/src/sqlite-adapter.ts
index c95fe3cc8..6c0c5ed9e 100644
--- a/packages/sqlite/src/sqlite-adapter.ts
+++ b/packages/sqlite/src/sqlite-adapter.ts
@@ -207,7 +207,7 @@ export class SQLiteConnectionPool extends SQLConnectionPool {
         }
 
         const connection = this.firstConnection && this.firstConnection.released ? this.firstConnection :
-            this.activeConnections > this.maxConnections
+            this.activeConnections >= this.maxConnections
                 //we wait for the next query to be released and reuse it
                 ? await asyncOperation<SQLiteConnection>((resolve) => {
                     this.queue.push(resolve);
diff --git a/packages/sqlite/tests/sqlite.spec.ts b/packages/sqlite/tests/sqlite.spec.ts
index 7b94ba162..f8e838916 100644
--- a/packages/sqlite/tests/sqlite.spec.ts
+++ b/packages/sqlite/tests/sqlite.spec.ts
@@ -2,7 +2,7 @@ import { expect, test } from '@jest/globals';
 import { SQLitePlatform } from '../src/sqlite-platform';
 import { databaseFactory } from './factory';
 import { User, UserCredentials } from '@deepkit/orm-integration';
-import { SQLiteDatabaseAdapter, SQLiteDatabaseTransaction } from '../src/sqlite-adapter';
+import { SQLiteConnection, SQLiteDatabaseAdapter, SQLiteDatabaseTransaction } from '../src/sqlite-adapter';
 import { sleep } from '@deepkit/core';
 import { AutoIncrement, cast, Entity, entity, PrimaryKey, Reference, ReflectionClass, serialize, typeOf, UUID, uuid } from '@deepkit/type';
 import { Database, DatabaseEntityRegistry } from '@deepkit/orm';
@@ -229,6 +229,8 @@ test('connection pool', async () => {
 
         const c3 = await sqlite.connectionPool.getConnection();
         expect(c3 === c1).toBe(true);
+
+        c3.release();
     }
 
     {
@@ -265,6 +267,32 @@ test('connection pool', async () => {
     }
 });
 
+test(':memory: connection pool', async () => {
+    const sqlite = new SQLiteDatabaseAdapter(':memory:');
+
+    // create a connection, or return null if it takes longer than 100 ms
+    const createConnectionOrNull = () => Promise.race([
+        sqlite.connectionPool.getConnection(),
+        sleep(0.1).then(() => null),
+    ])
+
+    {
+        const c1 = await sqlite.connectionPool.getConnection();
+        const c2 = await createConnectionOrNull();
+        const c3 = await createConnectionOrNull();
+
+        expect(sqlite.connectionPool.getActiveConnections()).toBeLessThanOrEqual(sqlite.connectionPool.maxConnections);
+
+        expect(c1).toBeDefined();
+        expect(c2).toBeNull();
+        expect(c3).toBeNull();
+
+        c1.release();
+        c2?.release();
+        c3?.release();
+    }
+});
+
 test('optional', async () => {
     @entity.name('entity')
     class MyEntity {