Running a cell which has Bash code with a missing delimiter causes `ValueError: Continuation prompt found - input was incomplete:` in Jupyter log

[ackalker]

Running a cell with some missing delimiter (see screenshot above) produces the following error output in my Jupyter log, and requires interrupting the kernel to be able to continue working:

[I 2022-02-09 11:08:39.046 ServerApp] Creating new notebook in /Documents/JupyterLab
[I 2022-02-09 11:08:39.582 ServerApp] Kernel started: a8654c4f-a53d-49f5-a022-e71746be6b85
[IPKernelApp] ERROR | Exception in message handler:
Traceback (most recent call last):
  File "/home/miki/.pyenv/versions/jupyterlab/lib/python3.10/site-packages/ipykernel/kernelbase.py", line 357, in dispatch_shell
    await result
  File "/home/miki/.pyenv/versions/jupyterlab/lib/python3.10/site-packages/ipykernel/kernelbase.py", line 647, in execute_request
    reply_content = self.do_execute(
  File "/home/miki/.pyenv/versions/jupyterlab/lib/python3.10/site-packages/bash_kernel/kernel.py", line 143, in do_execute
    self.bashwrapper.run_command(code.rstrip(), timeout=None)
  File "/home/miki/.pyenv/versions/jupyterlab/lib/python3.10/site-packages/pexpect/replwrap.py", line 107, in run_command
    raise ValueError("Continuation prompt found - input was incomplete:\n"
ValueError: Continuation prompt found - input was incomplete:
echo "This string is missing a closing quote
[I 2022-02-09 11:10:40.393 ServerApp] Saving file at /Documents/JupyterLab/valueerror_continuation_prompt_found.ipynb

Missing a closing quote, parenthesis or fi, esac or done is a quite common occurrence when writing shell commands. It would be nice if bash_kernel would report the error in the cell output instead of in the Jupyter log.

[takluyver]

Yes, it should probably catch that ValueError and send it to the user as an error message. PRs welcome.