`jupytext --execute` causes `NameError: name __session__ is not defined`

[ctcjab]

When I execute Jupytext py:percent formatted notebooks in Jupyter Lab that use the __session__ variable to resolve the path to the notebook, it works.

When I execute such notebooks via jupytext --execute, it fails with NameError: name __session__ is not defined.

repro.py:

# ---
# jupyter:
#   jupytext:
#     cell_metadata_filter: -all
#     formats: py:percent
#     text_representation:
#       extension: .py
#       format_name: percent
#       format_version: '1.3'
#       jupytext_version: 1.16.7
#   kernelspec:
#     display_name: base
#     language: python
#     name: python3
# ---

# %%
print(f"{__session__=}")

Works in Jupyter Lab:

Fails when run via jupytext CLI:

❯ jupytext --execute ~/repro.py
[jupytext] Reading /home/jovyan/repro.py in format py
[jupytext] Executing notebook with kernel python3
Traceback (most recent call last):
  File "/opt/conda/bin/jupytext", line 10, in <module>
    sys.exit(jupytext())
             ^^^^^^^^^^
  File "/opt/conda/lib/python3.12/site-packages/jupytext/cli.py", line 497, in jupytext
    exit_code += jupytext_single_file(nb_file, args, log)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.12/site-packages/jupytext/cli.py", line 734, in jupytext_single_file
    exec_proc.preprocess(notebook, resources=resources)
  File "/opt/conda/lib/python3.12/site-packages/nbconvert/preprocessors/execute.py", line 103, in preprocess
    self.preprocess_cell(cell, resources, index)
  File "/opt/conda/lib/python3.12/site-packages/nbconvert/preprocessors/execute.py", line 124, in preprocess_cell
    cell = self.execute_cell(cell, index, store_history=True)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.12/site-packages/jupyter_core/utils/__init__.py", line 165, in wrapped
    return loop.run_until_complete(inner)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.12/asyncio/base_events.py", line 691, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.12/site-packages/nbclient/client.py", line 1062, in async_execute_cell
    await self._check_raise_for_error(cell, cell_index, exec_reply)
  File "/opt/conda/lib/python3.12/site-packages/nbclient/client.py", line 918, in _check_raise_for_error
    raise CellExecutionError.from_cell_and_msg(cell, exec_reply_content)
nbclient.exceptions.CellExecutionError: An error occurred while executing the following cell:
------------------
print(f"{__session__=}")
------------------


---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[1], line 1
----> 1 print(f"{__session__=}")

NameError: name '__session__' is not defined

In the meantime, is there some other way that a notebook can resolve its own path at runtime? I checked and the __file__ variable is not set either. Thanks in advance for any help!

[mwouts]

Hi @ctcjab , I am afraid this has to do with a difference in how notebooks are executed in Jupyter Lab or nbconvert, which Jupytext uses (see the stack trace above).

Can I suggest that you confirm that the issue is there with the command line jupyter nbconvert (with an .ipynb notebook), and if so, raise an issue at https://github.com/jupyter/nbconvert ?

[ctcjab]

Thanks @mwouts, done in https://github.com/jupyter/nbconvert/issues/2213