Cursor: avoid closing connection twice if error received after destroy()

packages/pg-cursor/index.js

@@ -151,6 +151,9 @@ class Cursor extends EventEmitter {
   }
 
   handleError(msg) {
+    // If this cursor has already closed, don't try to handle the error.
+    if(this.state === 'done') return;
+
     // If we're in an initialized state we've never been submitted
     // and don't have a connection instance reference yet.
     // This can happen if you queue a stream and close the client before

packages/pg-query-stream/test/error.ts

@@ -89,4 +89,46 @@ describe('error recovery', () => {
       await client.end()
     })
   })
+
+  it('should work if used after timeout error', async () => {
+    const pool = new Pool({ max: 1, connectionTimeoutMillis: 400, statement_timeout: 400 });
+
+    const res1 = await pool.query('SELECT 1 AS a');
+    assert.deepStrictEqual(res1.rows, [ { a:1 } ]);
+
+    const query = new QueryStream('SELECT 2 AS b');
+    const client = await pool.connect();
+    const stream = await client.query(query);
+
+    await assert.rejects(() => pool.query('SELECT TRUE'), { message: 'timeout exceeded when trying to connect' });
+
+    await stream.destroy();
+    await client.release();
+
+    const res2 = await pool.query('SELECT 4 AS d');
+    assert.deepStrictEqual(res2.rows, [ { d:4 } ]);
+
+    await pool.end();
+  })
+
+  it('should work if used after syntax error', async () => {
+    const pool = new Pool({ max: 1, statement_timeout: 100 }); // statement_timeout is required here, so maybe this is just another timeout error?
+
+    const res1 = await pool.query('SELECT 1 AS a');
+    assert.deepStrictEqual(res1.rows, [ { a:1 } ]);
+
+    const query = new QueryStream('SELECT 2 AS b');
+    const client = await pool.connect();
+    const stream = await client.query(query);
+
+    await new Promise(resolve => setTimeout(resolve, 10));
+
+    await stream.destroy();
+    await client.release();
+
+    const res2 = await pool.query('SELECT 4 AS d');
+    assert.deepStrictEqual(res2.rows, [ { d:4 } ]);
+
+    await pool.end();
+  })
 })