ImportError: cannot import name 'passwd' from 'IPython.lib'

TL;DR: IPython removed passwd from IPython.lib. Import it from notebook.auth instead.

The error

ImportError: cannot import name 'passwd' from 'IPython.lib'

Fix it

1. Replace the import:

   from notebook.auth import passwd

Expected: no import error.

1. For a version-proof script, gate it:

   try:
       from notebook.auth import passwd
   except ImportError:
       from IPython.lib import passwd

1. Verify:

   python -c "from notebook.auth import passwd; print(passwd('x')[:6])"

Expected: prints the start of a hash like argon2:.

When this applies

Use this when a setup script does from IPython.lib import passwd on modern IPython.

When it does not apply

If the error names a different IPython.lib member, look up its new home. If notebook is not installed, install it; notebook.auth is where the function lives now.

Compatibility

Modern IPython (7+) with notebook installed. Very new jupyterserver-based setups moved it again to jupyterserver.auth; check if notebook.auth is absent.

Root cause

passwd generated the password hash for the classic notebook server. When auth moved with the server code, IPython dropped its copy, and scripts importing the old path break.

Edge cases

If you are hashing passwords for jupyterserver (not classic notebook), import from jupyterserver.auth instead. Never log or print full password hashes; they are secrets.