PapermillExecutionError cannot be loaded from picklefile

[Calder-Ty]

🐛 Bug

As part of my team's workflow, we extensively use Papermill to run notebooks as part of our Apache Airflow pipelines. When upgrading Airflow to version 2.X.X we found that our default error handling tools were no longer providing detailed errors from our PapermIll tasks. The cause for this is that Airflow changed the way it handles errors in it's tasks. It temporarily pickles the error message, and then at a later point loads the pickled exception.

Because PapermillExecutionError is called with multiple arguments, but then only passes up a message argument to its superclass, pickle is unable to load it. See this stack overflow question/answer for a general case of this issue.

This error can be recreated with this simple test:

import tempfile
import pickle

from papermill.exceptions import PapermillExecutionError

def test_exceptions_are_unpickleable():
    """Ensure exceptions can be unpickled"""
    temp_file = NamedTemporaryFile()
    err = PapermillExecutionError(1,2, "TestSource", "Exception", Exception(), ["Traceback", "message"])

    with open(temp_file.name, 'wb') as fd:
        pickle.dump(err, fd)
    # Read the Pickled File
    temp_file.seek(0)
    data = temp_file.read()
    pickled_err = pickle.loads(data)
    assert str(pickled_err) == str(err)

[Calder-Ty]

The accompanying pull request resolves this issue.