Queued with some typo fixes, thanks.

Queued, thanks. We'll probably need selector.close() somewhere.

if pycompat.isposix or pycompat.iswindows:
    _STARTUP_COST = 0.01

+ # The Windows worker is thread based. If tasks are CPU bound, threads
+ # in the presence of the GIL result in excessive context switching and
+ # this overhead can slow down execution.
+ _DISALLOW_THREAD_UNSAFE = True

In D3964#61696, @glandium wrote:

This is python code, why is it parsing the version file instead of importing it?

Hmm and nevermind, the weird package name doesn't reproduce on a vanilla hg build, you can go ahead and review.

This is python code, why is it parsing the version file instead of importing it?

Er, actually, let me fix this again - this unbreaks the build but generates packages like 'Mercurial-"4.6.2+674-f83600efa1ca-macosx10.13.dmg'.

And, should we drop the --no-backup option? @pulkit what do you think?

Yep, we should either have this option everywhere or not have it anywhere. I too think that config option is better suited here. Let's drop it and comment on the bug which needed the flag about the config option.

How do we drop a feature? Do I need to remove all the code related to --no-backup option?