panel 0.13 JupyterLab preview: 'Resources' object has no attribute 'absolute'

[marcelmindemann]

ALL software version info

I created a minimal virtual environment using:
panel 0.13
jupyterlab 3.3.4
using Python 3.10.

Description of expected behavior and the observed behavior

I am using your unaltered example notebook at https://github.com/holoviz/panel/blob/master/examples/gallery/apis/stocks_altair.ipynb. I open this notebook in JupyterLab.
When using the "Render with Panel" button in JupyterLab, it yields a 500 Internal Server error.

The log of JupyterLab shows this error:

[E 2022-04-22 17:44:28.816 ServerApp] Uncaught exception GET /panel-preview/render/.venv/lib/python3.10/site-packages/panel/examples/gallery/apis/stocks_altair.ipynb (::1)
    HTTPServerRequest(protocol='http', host='localhost:8889', method='GET', uri='/panel-preview/render/.venv/lib/python3.10/site-packages/panel/examples/gallery/apis/stocks_altair.ipynb', version='HTTP/1.1', remote_ip='::1')
    Traceback (most recent call last):
      File "/Users/marcel.mindemann/experiments/panel-clean-install/.venv/lib/python3.10/site-packages/tornado/web.py", line 1704, in _execute
        result = await result
      File "/Users/marcel.mindemann/experiments/panel-clean-install/.venv/lib/python3.10/site-packages/panel/io/jupyter_server_extension.py", line 116, in get
        page = server_html_page_for_session(
      File "/Users/marcel.mindemann/experiments/panel-clean-install/.venv/lib/python3.10/site-packages/bokeh/embed/server.py", line 255, in server_html_page_for_session
        bundle = bundle_for_objs_and_resources(None, resources)
      File "/Users/marcel.mindemann/experiments/panel-clean-install/.venv/lib/python3.10/site-packages/bokeh/embed/bundle.py", line 211, in bundle_for_objs_and_resources
        js_files.extend(js_resources.js_files)
      File "/Users/marcel.mindemann/experiments/panel-clean-install/.venv/lib/python3.10/site-packages/panel/io/resources.py", line 299, in js_files
        dist_dir = self.dist_dir
      File "/Users/marcel.mindemann/experiments/panel-clean-install/.venv/lib/python3.10/site-packages/panel/io/resources.py", line 259, in dist_dir
        if self.absolute:
    AttributeError: 'Resources' object has no attribute 'absolute'

Complete, minimal, self-contained example code that reproduces the issue

I am running the jupyterlab server with

poetry run jupyter lab

[philippjfr]

Thanks for reporting this! This has already been fixed on master here: #3399 and I'll release it as soon as I get a chance in 0.13.1.