node-pty write lock on macOS

test.js

// Run: node test.js test.py

const pty = require('node-pty');
const fs = require('fs');
const path = require('path');
const net = require('net');

const ptyProcess = pty.spawn('zsh', [], {
  name: "xterm-color",
  cols: 80,
  rows: 30,
  cwd: process.env.HOME,
  env: process.env
});

ptyProcess.on('data', function (data) {
  process.stdout.write(data);
});

let writeTimeout;
let chunks;
let socket;
//const socketPath = '/tmp/my_unix_socket';
//const server = net.createServer();

function chunkInput(data) {
  const chunks = [];
  let nextChunkStartIndex = 0;
  for (let i = 0; i < data.length - 1; i++) {
    if (
      // If the max chunk size is reached
      i - nextChunkStartIndex + 1 >= 50 ||
      // If the next character is ESC, send the pending data to avoid splitting the escape
      // sequence.
      data[i + 1] === '\x1b'
    ) {
      chunks.push(data.substring(nextChunkStartIndex, i + 1));
      nextChunkStartIndex = i + 1;
      // Skip the next character as the chunk would be a single character
      i++;
    }
  }
  // Push final chunk
  if (nextChunkStartIndex !== data.length) {
    chunks.push(data.substring(nextChunkStartIndex));
  }
  return chunks;
}

function startWrite() {
  // Don't write if it's already queued of is there is nothing to write
  if (writeTimeout !== undefined || chunks.length === 0) {
    return;
  }

  //socket.write(Buffer.from(chunks.shift(), 'binary'));
  ptyProcess.write(Buffer.from(chunks.shift(), 'binary'));

  // Don't queue more writes if the queue is empty
  if (chunks.length === 0) {
    chunks = undefined;
    console.log('All chunks written');
    return;
  }

  // Queue the next write
  writeTimeout = setTimeout(() => {
    writeTimeout = undefined;
    startWrite();
  }, 5);
}

function chunkFile(filePath) {
  try {
    // Read the file with binary encoding
    const data = fs.readFileSync(filePath, 'binary');

    // Chunk size in bytes
    chunks = chunkInput(data);

    /*server.listen(socketPath, () => {
      console.log(`Server listening on ${socketPath}`);
      socket = net.createConnection({ path: socketPath });
      socket.setEncoding('utf8');
      socket.writable = true;
    });
    server.on('connection', (socket) => {
      console.log('Client connected');
      startWrite();
      socket.on('data', (data) => {
        process.stdout.write(data);
      });
      socket.on('end', () => {
        console.log('Client disconnected');
      });
      socket.on('error', (err) => {
        console.error('Socket error:', err);
      });
    });*/
    startWrite();
  } catch (error) {
    console.error(`Error reading file: ${error.message}`);
    process.exit(1);
  }
}

// Get file path from command line arguments
const filePath = process.argv[2];
const resolvedPath = path.resolve(filePath);
chunkFile(resolvedPath);

test.py

import time

time.sleep(1)

def longfunction():
    '''
    Contains 200 print('hello') statements,
    each on a new line. Nothing else.
    '''
    
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')
    print('hello')