Fix suite freeze on non-existent xtrigger - 7.8.x

[dwsutherland]

Port of pull/3056

[kinow]

Travis is unhappy because of an error with pycodestyle I believe.

lib/cylc/config.py:2107:33: E128 continuation line under-indented for visual indent
lib/cylc/config.py:2110:29: E128 continuation line under-indented for visual indent
The command "pycodestyle --ignore=E402,W503,W504 lib/cylc lib/Jinja2Filters/*.py lib/parsec/*.py $(grep -l '#!.*\<python\>' bin/*)" exited with 1.

(this error appears near the top of the output, which is misleading, as you normally expect the error near the bottom of the file/output)

[dwsutherland]

(this error appears near the top of the output, which is misleading, as you normally expect the error near the bottom of the file/output)

I couldn't see that log detail at all, was just the working info.. anyways fixed.

[matthewrmshin]

Given the final comments under #3056, do we need to raise a new PR against master for a test and back port that here?

[matthewrmshin]

Happy to merge this otherwise, and have separate back port PR for test.

[matthewrmshin]

Is that #3060?

[dwsutherland]

Given the final comments under #3056, do we need to raise a new PR against master for a test and back port that here?

correct

Not here sorry; New test PR port of 3060 to come post merge of this one.

[kinow]

Not here sorry; New test PR port of 3060 to come post merge of this one.

Yup, I merged it too quickly, sorry. So now we will have yet another backport pull request. Mea culpa 😞 I'll submit it once both get merged.

[dwsutherland]

Not here sorry; New test PR port of 3060 to come post merge of this one.

Yup, I merged it too quickly, sorry. So now we will have yet another backport pull request. Mea culpa 😞 I'll submit it once this gets merged.

Worked out well, since your test construction > mine ATM (>.<) ... Gave me a chance to use yours as a tutorial.

[kinow]

Hmmm, just realized you have ModuleNotFoundError on master, and the parent class ImportError on 7.8.x. I think we better use the parent ImportError on master too @dwsutherland . WDYT?

[dwsutherland]

@kinow - Yes, as python3 gave me ModuleNotFoundError, but python2 produced ImportError and the former is not recognised. I didn't try ImportError in python3 (Is it back compat?), and figured both have diverged anyway.. Is this ok?

[hjoliver]

Interesting (another hole in my Python 3 knowledge!).

[kinow]

I believe ImportError is the parent class of ModuleNotFoundError.

Interesting (another hole in my Python 3 knowledge!).

Me too! I thought at least this part was consistent in both. But catching the parent class should be fine, though better to confirm if that works. Perhaps the unit tests could be used to validate that it works?

[dwsutherland]

I believe ImportError is the parent class of ModuleNotFoundError.

Well I guess the child doesn't exist in python2 ... Consistency aside, would it have been better to use the parent?

Also does consistency matter between 7.8.x and 8? at some point we'll stop back porting changes? (as I guess it matters for that)

[kinow]

Good point. If that works as-is, all good then I think