ipywidgets 8.x fails to install on Windows via Poetry due to path length, but 7.7.0 works

[enricostragiotti]

Description

Installing ipywidgets version 8.1.8 (and likely other 8.x and >7.7.0 releases) on Windows 11 using Poetry (version 2.2.1, Python 3.10.11) results in a failure during dependency installation due to extremely long/nested file paths generated by bundled labextension files. The problematic file is:

share\jupyter\labextensions\@jupyter-widgets\jupyterlab-manager\static\vendors-node_modules_d3-color_src_color_js-node_modules_d3-format_src_defaultLocale_js-node_m-09b215.2643c43f22ad111f4f82.js

The error is:

FileNotFoundError
[Errno 2] No such file or directory: '...\@jupyter-widgets\jupyterlab-manager\static\vendors-node_modules_d3-color_src_color_js-node_modules_d3-format_src_defaultLocale_js-node_m-09b215.2643c43f22ad111f4f82.js'

This is due to Windows default path length restrictions (260 characters). The workaround is to pin ipywidgets==7.7.0, which installs jupyterlab-widget v1.1.11 and works correctly. For users in managed/corporate environments, enabling long-path support is often not feasible without special IT approval.

Reproduce

Environment:

• Windows 11 (default, no long-path enabled)
• Poetry v2.2.1
• Python 3.10.11

Steps:

1. Create a new Python environment/project (e. g., with Poetry)
2. Run poetry add ipywidgets==8.1.8
3. Observe installation failure with path length error on the above file
4. Run poetry add ipywidgets==7.7.0 and observe successful install

[nathanjmcdougall]

Related: astral-sh/uv#16877

[ArthurGW]

Just to note that I encountered this issue, and the issue is specifically in the jupyterlab-widgets dependency.

As a workaround, for now users can pin to jupyterlab-widgets==3.0.15, which does not have the path issue, and is still compatible with ipywidgets==8.1.8 as far as I can tell.