Avoid repeated connect lease deadlock

Author: HenkDz

src/utils/connection.test.ts

@@ -644,6 +644,47 @@ describe('DatabaseConnection lifecycle', () => {
     }
   });
 
+  it('reuses an active same-pool connection without waiting on its lease', async () => {
+    const release = vi.fn();
+    const client = {
+      query: vi.fn().mockResolvedValue({ rows: [] }),
+      release
+    };
+    const pool = {
+      connect: vi.fn().mockResolvedValue(client),
+      on: vi.fn(),
+      end: vi.fn().mockResolvedValue(undefined)
+    };
+    const Pool = vi.fn(() => pool);
+
+    vi.resetModules();
+    vi.doMock('pg', () => ({ default: { Pool } }));
+    vi.doMock('pg-monitor', () => ({
+      default: {
+        attach: vi.fn(),
+        setTheme: vi.fn()
+      }
+    }));
+
+    try {
+      const { DatabaseConnection: FreshDatabaseConnection } = await import('./connection');
+      const db = FreshDatabaseConnection.getInstance();
+
+      await db.connect('postgresql://same');
+      await db.connect('postgresql://same');
+
+      expect(Pool).toHaveBeenCalledTimes(1);
+      expect(pool.connect).toHaveBeenCalledTimes(1);
+      expect(client.query).toHaveBeenCalledTimes(1);
+
+      await FreshDatabaseConnection.cleanupPools();
+    } finally {
+      vi.doUnmock('pg');
+      vi.doUnmock('pg-monitor');
+      vi.resetModules();
+    }
+  });
+
   it('releases the connection lease when connect validation fails', async () => {
     const release = vi.fn();
     const client = {

src/utils/connection.ts

@@ -263,25 +263,30 @@ export class DatabaseConnection {
    * Connect to a PostgreSQL database
    */
   public async connect(connectionString?: string, options: ConnectionOptions = {}): Promise<void> {
-    await this.acquireConnectionLease();
-    let connectionStateChanged = false;
+    // Use environment variable only when no explicit connection string was provided.
+    const connString = connectionString !== undefined ? connectionString : process.env.POSTGRES_CONNECTION_STRING;
+    const effectiveOptions = {
+      ...getDefaultConnectionOptions(),
+      ...options
+    };
+
+    if (connString === undefined || connString.trim() === '') {
+      throw new Error('No non-empty connection string provided and POSTGRES_CONNECTION_STRING environment variable is not set');
+    }
 
-    try {
-      // Use environment variable only when no explicit connection string was provided.
-      const connString = connectionString !== undefined ? connectionString : process.env.POSTGRES_CONNECTION_STRING;
-      const effectiveOptions = {
-        ...getDefaultConnectionOptions(),
-        ...options
-      };
+    assertConnectionOptions(effectiveOptions);
+    const poolCacheKey = buildPoolCacheKey(connString, effectiveOptions);
 
-      if (connString === undefined || connString.trim() === '') {
-        throw new Error('No non-empty connection string provided and POSTGRES_CONNECTION_STRING environment variable is not set');
-      }
+    // If already connected to this database, reuse the connection without waiting on our own active lease.
+    if (this.pool && this.poolCacheKey === poolCacheKey) {
+      return;
+    }
 
-      assertConnectionOptions(effectiveOptions);
-      const poolCacheKey = buildPoolCacheKey(connString, effectiveOptions);
+    await this.acquireConnectionLease();
+    let connectionStateChanged = false;
 
-      // If already connected to this database, reuse the connection
+    try {
+      // Another queued connect may have established the requested pool while we waited.
       if (this.pool && this.poolCacheKey === poolCacheKey) {
         return;
       }