fix: circular dependencies error when there are none

[browniebroke]

I have the same issue as the one reported in #1397. I'm not sure I can fix it, but I thought it would be helpful to at least write a test reproducing the issue.

Fix #1397

Implementation note

I initially had:

• chained1 depends on chained2, chained3
• chained2 depends on chained3
• chained3 depends on nothing

But this worked fine, there was no problem. It looks like the problem depends on the plugin names, I can reproduce with:

• chained3 depends on chained2 and chained1
• chained2 depends on chained1
• chained1 depends on nothing

Checklist

• Add a new test case reproducing the problem reported in Circular Dependencies when there are none #1397
• Fix the problem

[sijis]

I really appreciate you putting this together.

Could you elaborate what you mean by

It looks like the problem depends on the plugin names

Maybe its late but I'm missing but both scenarios looks similar if not identical to me.

[browniebroke]

I agree, the 2 cases should be equivalent, but one passes the test I wrote while the other doesn't. Since the only difference is with the names I assumed that it's playing a role into the problem.

I guess the plugin discovery system order plugins somehow related to their names. If the name ordering matches the dependency ordering, they can start, otherwise they can't.

[browniebroke]

This new error happens because this line returns None:

https://github.com/browniebroke/errbot/blob/c81c78ec29592cb17d29f3aaa4b954f23f9a77ce/errbot/plugin_manager.py#L431

Which cause an attribute error down here:

https://github.com/browniebroke/errbot/blob/c81c78ec29592cb17d29f3aaa4b954f23f9a77ce/errbot/plugin_manager.py#L439

Open to suggestions on how to fix it better.

[tmcevoy14]

Hi @browniebroke any idea when this fix will be merged?

[browniebroke]

No idea, no, it's not really up to me at this point. I think the next step would be for a maintainer to assess whether they are happy with my code of if they have any suggestions. This is probably not the only thing on their plate, though...

In the meantime, if you want to help, I'm sure they would appreciate if you could try my version out and see if it maybe has a bug in it. You can install from source with pip:

pip install -e git+https://github.com/browniebroke/errbot.git@36920efa7818d71d4d9dc839100385f384d4c665#egg=errbot

You can put the part after pip install in your requirements file too. If you find any problem or if it works like a charm, please report back here.

[sijis]

@browniebroke @tmcevoy14 Would you folks be able to see if this issue persist with the latest changes on master branch?