Alright that test seems a bit ridiculous now that I'm looking at it in the diff, but it's at least thorough? :)

Why wouldn't we want automated, non-interactive tools to have the benefits of watchman? There are plenty of use cases where complex Mercurial operations are scripted and would benefit from watchman.

This new config knob defaults to off and we're therefore changing the behavior to not warn when watchman is unavailable. This is a bit concerning to me because someone could have fsmonitor enabled and I don't think they'd ever get an error if watchman isn't working correctly.

In D5496#82671, @yuja wrote:

> `[, samebranch]` or [, samebranch=False]`.
I guess that means:
@predicate('merge([withbranch [, samebranch=None]])', safe=True)
Right? (I realized that it is incorrect to say that samebranch's default value is False).

Okay, I didn't notice that. And it's tricky to map samebranch=False to
"different branch" constraint. I would read it as "I don't care whether
the branches are the same or not."

In D5602#82808, @pulkit wrote:

It's weird that print works as a function too in Python 2.

It's weird that print works as a function too in Python 2.

In D5599#82802, @pulkit wrote:

Let's use pycompat.queue() for consistency.

Let's use pycompat.queue() for consistency.

In D5510#82651, @yuja wrote:

Fixed pyflakes warnings in flight.

hgext/narrow/narrowcommands.py:13: 'mercurial.merge' imported but unused
hgext/narrow/narrowcommands.py:262: local variable 'newmatch' is assigned to but never used

@yuja the doc you're linking is about integration tests, so it wouldn't apply to these tests which are really unitary in my mind. Usually the main difference would be the access to the private constructs that the integration tests can't perform, but it's true that most of these implementations are public anyway.

I haven't handled your other remark,

> `[, samebranch]` or [, samebranch=False]`.
I guess that means:
@predicate('merge([withbranch [, samebranch=None]])', safe=True)
Right? (I realized that it is incorrect to say that samebranch's default value is False).