Add except declaration in Cython interface for regex_program::create

[davidwendt]

Description

Add the except + declaration to the cudf::strings::regex_program::create() function in the Cython regex_program.pxd interface since invalid regex patterns are thrown by this call. This allows the normal Cython exception handling to pass the exception to the Python logic without aborting the process.

Closes #13052

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[bdice]

Changes look good. Should we add a test?

[bdice]

Proposed test:

def test_invalid_regex():
    s = cudf.Series(["a"])
    with pytest.raises(RuntimeError):    # Might be the wrong error class, please verify
        s.str.extract("{\}")    # Should this be a raw string like `r"{\}"`?

[davidwendt]

Changes look good. Should we add a test?

Yes, thanks.
Also, I was wondering about changing the libcudf exception to something more specific like std::invalid_argument for poorly formed regex pattern. I could do that in a follow up PR. Just requesting opinions.

[shwina]

LGTM, pending @bdice's suggestions for testing

[bdice]

Also, I was wondering about changing the libcudf exception to something more specific like std::invalid_argument for poorly formed regex pattern. I could do that in a follow up PR. Just requesting opinions.

I think that’d be fine. I am not up to date on the latest guidelines / changes for exception types so I don’t know exactly what to recommend. I know we’ve been pushing to improve that recently.

[davidwendt]

/merge