The "path" argument must be of type string. Received undefined

[andresgutgon]

Describe the bug

What?

I'm aware that there is already this issue #180 in that issue the solution is to update NodeJS to v22. But this is my situation

Error

The "path" argument must be of type string. Received undefined
Almost all bash operations like cd, ls, cat are failing for me

## System Report
macOS:       26.1 (25B78)
iTerm2:      3.5.13
tmux:        tmux 3.4
Node.js:     v22.14.0
Copilot CLI: 0.0.358

I'm using pnpm for managing the install of copilot. And nvm for nodejs version

 which node
/Users/andres/.nvm/versions/node/v22.14.0/bin/node

Affected version

0.0.358

Steps to reproduce the behavior

 ✗ Check if Preview module exists
   $ cd /Some/path/in/my/machine && find 
   packages/some/path/lib -name "*preview*.ex" -type f
   The "path" argument must be of type string. Received undefined

Expected behavior

No response

Additional context

No response

[andresgutgon]

It's very frustrating. Makes the CLI almost useless :/

[JuanCS-Dev]

🔬 Investigation: This is NOT the same as #180

I've analyzed this issue and it's fundamentally different from the closed issue #180.

❌ Issue #180 (Closed)

• Cause: Node.js < 22
• Solution: Upgrade to Node 22+
• Status: Fixed with version check

🚨 Issue #581 (THIS ONE)

• Environment: Already has Node v22.14.0 ✅
• Cause: Unknown (different root cause)
• Status: Active bug affecting latest CLI version

---

Root Cause Hypotheses

H1: tmux + CWD Resolution Failure ⭐⭐⭐⭐ (Most Likely)

Evidence:

• You're running in tmux 3.4
• Error: The "path" argument must be of type string. Received undefined
• This suggests process.cwd() returns undefined

Why tmux breaks it:

// Copilot's bash tool likely does:
const cwd = process.cwd();  // Returns undefined in tmux!
fs.someOperation(cwd, ...); // ❌ Throws: path must be string

tmux can break Node.js process.cwd() in certain configurations because it doesn't properly inherit the working directory from the parent shell.

---

H2: pnpm + nvm Interaction ⭐⭐

Evidence:

• Using pnpm (not npm) to install
• Using nvm for Node version management
• pnpm has different symlink/module resolution

Possible issue:

• pnpm's global install path might conflict with nvm
• Node binary path resolution fails
• Working directory context gets lost

---

H3: macOS Sequoia (26.1) API Changes ⭐

Evidence:

• macOS 26.1 is very recent (latest Sequoia)
• New security restrictions on file system access
• process.cwd() might be blocked by new security model

---

Test 1: Verify tmux is the culprit

# Exit tmux completely
tmux detach

# Run copilot in regular iTerm2 (no tmux)
copilot --allow-all-tools -p "run command: pwd"

Expected: If it works outside tmux → tmux is confirmed culprit

---

Test 2: Check Node environment inside tmux

# Inside your tmux session
node -e "console.log('cwd:', process.cwd())"
node -e "console.log('env.PWD:', process.env.PWD)"

Expected: If cwd is undefined or throws error → confirms hypothesis

---

Test 3: Try npm instead of pnpm

pnpm uninstall -g @github/copilot
npm install -g @github/copilot@0.0.358

# Try again in tmux
copilot --allow-all-tools -p "run: pwd"

---

Test 4: Try regular Terminal.app

# Open Terminal.app (not iTerm2)
# Start copilot
copilot --allow-all-tools -p "run: pwd"

---

⚡ Immediate Workarounds

Workaround 1: Set explicit PWD before running

# In your tmux session, before running copilot:
export PWD=$(pwd)
copilot

Workaround 2: Use copilot outside tmux

# Just use iTerm2 directly
copilot

Workaround 3: tmux attach with proper env

# When attaching to tmux, preserve environment
tmux attach-session -t <session> -E PWD=$(pwd)

---

🔧 Proposed CLI Fixes

Fix 1: Defensive CWD Resolution

function getCurrentWorkingDirectory(): string {
  try {
    const cwd = process.cwd();
    if (typeof cwd === 'string' && cwd.length > 0) {
      return cwd;
    }
  } catch (error) {
    // process.cwd() failed
  }
  
  // Fallback chain
  return process.env.PWD || process.env.HOME || '/tmp';
}

Fix 2: Better Error Message

function executeBash(command: string, options: any) {
  const cwd = getCurrentWorkingDirectory();
  
    throw new Error(
      'Cannot determine current working directory.\n' +
      'This is often caused by running in tmux.\n' +
      'Workaround: export PWD=$(pwd) before running copilot'
    );
  }
  
  // ... rest of implementation
}

Fix 3: Environment Validation at Startup

// Check environment on CLI startup
  console.warn('⚠️  Warning: Running in tmux with invalid working directory');
  console.warn('💡 Workaround: export PWD=$(pwd)');
}

---

📊 Information Needed

To help resolve this, please provide:

1. Result of Test 1: Does it work outside tmux?
2. Output of Test 2: What does process.cwd() return in tmux?
3. tmux config: Can you share your .tmux.conf?
4. Installation method: Output of which copilot and which node

---

Impact Assessment

Severity: High
Scope: macOS + tmux users (likely affects many developers)
Workaround: Available (export PWD=$(pwd))
Root Cause: Environment variable handling in bash tool

---

I believe this is a fixable bug in the CLI's bash tool implementation. The fix should add defensive CWD resolution with proper fallbacks.

Would you be able to run the diagnostic tests and report back? This will help confirm the root cause and guide the fix.

[andresgutgon]

❌ Not working outside tmux
❌ Not working in native Mac Terminal

# Run copilot in regular iTerm2 (no tmux)
copilot --allow-all-tools -p "run command: pwd"

It's PNPM 🎉
I installed with npm and it works