I also think having multiple names for the same thing is quite confusing. I would love seeing bt/bt2 just decide for one wording and be consistent with it. I actually think data and datas[0] might be the only duplication I might see a benefit in.

I see to ways:

1. Daniel expresses his plans how to continue with backtrader and then find a way how either he keeps doing it alone or give others also access to contribute to it
2. backtrader2 becomes a project independent from original backtrader (including website, forum etc. etc.). This would be big step of course which means alot of effort and dedication.

No bad feelings but I am personally think in the long run there won't be a vivid collaboration between backtrader2 and backtrader without any form of agreement or approval with Daniel.

Nice to see original backtrader getting an update. As I understand the future situation about original backtrader, backtrader2 or possible contributions by other people to original backtrader is not decided yet.

I joined the backtrader2 orginazation (thank you) and updated its master branch to match original backtrader's master branch. Was basically a test but it worked and I think it was not wrong. I hope that was ok for you guys? I don't real know who is supposed to do/to be allowed to do stuff like this.

I have set up Travis CI on my fork to automatically run tests upon commit. Maybe it will help you:
https://travis-ci.com/github/verybadsoldier/backtrader

Both of the above has its own problems:

1. Most of the existing tests seems to be developed for manual run and inspection.

Hm, not sure. Which ones do you mean?
The ones that I am aware of can be run automatically, e.g.:
https://travis-ci.com/github/verybadsoldier/backtrader/jobs/295673688

2. Some parts of the code is hard to automatically test since interactions with external API could be required and there is no any mock interfaces or simulators available yet

Python's unittest package has quite good mocking features. So writing tests for external APIs shouldn't be hard. I think that is the standard way.

Thanks @vladisld, really nice! Looking forward to this!
Regarding the name: Might backtrader2 lead people into thinking that it is v2 of the official project? Maybe the name should indicate more that is is a fork of the official backtrader? Some people seem to already expect some sort of a version 2 of the offical project, e.g. https://community.backtrader.com/topic/2210/backtrader-2-0

I would be happy to contribute what I have to a new backtrader project. Doing the fork is easy I guess. But it needs someone to step up willing to bring the needed commitment to lead a new project.
Also maybe better keep the discussion in the existing thread?

I agree the situation is not ideal. But I totally respect that people move on and don't enjoy maintaining projects forever. So yeah, the usual flow of things is that someone steps up willing to either get commit rights to the official repo or establish a fork which is considered as a new "official" repo (bt-next? bt-ng anyone?) :)

It looks like there are several open bugs in the code since some time which I guess won't be fixed anymore. So when you plan to get into BT then be ready to work with the code to be able to cope with bugs/problems. It surely is worth it though. You can find some fixes/improvements in other people's BT forks.

E.g. when using live mode and resampling live ticks to M1 bars then you get gaps in the data lines when in a given minute no tick arrived. I am unsure how to handle this properly and I think I have read about backtrader being able to forward fill those gaps when data is missing.

Currently I fail to find any definite information about this topic. What I found is this which involves using data filters:
https://www.backtrader.com/blog/posts/2016-04-19-sync-different-markets/sync-different-markets/

Not sure if something similar could be used to handle the situation mentioned above. I am sure this topic has been discussed already. So maybe someone could point me in the right direction?
Thank you.

I guess you are trying to instantiate your strategy with an argument size which is unknown to your strategy?
But still, debugging code is alot easier when you actually can see the code in question :)