ThreadedHistory: invoke Buffer.new_history_item() on event loop from background thread

[bobhy]

Fixes issue #1158, and seems to work in Xonsh as well.

Depends on ThreadedHistory and Application being able to rendezvous on same event loop. While this may not be possible for history in general, I think it is an acceptable restriction on ThreadedHistory.

[bobhy]

Oh noes! many errors from mypy for code I haven't touched! Has there been a recent change to project build or is there some other trick I need to use to get the PR to pass?

OTOH, this check did find some nits in code I did touch, and I will push fixes for those...

[bobhy]

Resolved remaining mypy complaints, but why was this necessary?

[jonathanslenders]

Thanks for this. The Mypy errors are probably because of a new recent mypy release. I look into that.
(It's intentional that we use the latest mypy all the time, because it helps us discovering new possible bugs.)

Thanks again for the fix! I review it ASAP.

[jonathanslenders]

Hi @bobhy,

The mypy issues were solved in this PR: #1167 (comment) (slightly differently - I don't like to ignore errors.)

Can you rebase this branch on master, and squash the remaining changes?

[bobhy]

My git fu is weak. I have merged from master and will work on the rebase next.

[bobhy]

.. have rebased on master, but still cannot get rebase to squash my subsequent interim commits, need advise or help!

[bobhy]

I have successfully squashed all the commits, but now cannot merge that tree into this branch (error is "error: failed to push some refs, hint: Updates were rejected because the tip of squashed branch is behind its remote counterpart")

Will push nice, clean PR to new branch and close this one.