[PATCH 1 of 8] localrepo: reverse contexts in status

[Durham Goode]

On 5/6/14, 4:33 PM, Sean Farley wrote:
> # HG changeset patch
> # User Sean Farley <sean.michael.farley at gmail.com>
> # Date 1397684088 18000
> #      Wed Apr 16 16:34:48 2014 -0500
> # Node ID c8586e9a821d8abbc88438f2e78aa564e0b5e87a
> # Parent  0768cda8b5799dc803dc0ee27a832cd64e05f28a
> localrepo: reverse contexts in status
>
> This is a slight tweak to how localrepo.status calculates what files have
> changed. By forcing a changectx to be first operator and anything not a
> changectx to be the second operator, we can later exploit this to allow
> refactoring the status operation as a method of a context object.
>
> Furthermore, this change will speed up 'hg diff --reverse' when used with the
> working directory because the code will now hit a fast path without needing to
> calculate an unneeded second manifest.
>
> diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
> --- a/mercurial/localrepo.py
> +++ b/mercurial/localrepo.py
> @@ -1518,10 +1518,17 @@ class localrepository(object):
>               return mf
>   
>           ctx1 = self[node1]
>           ctx2 = self[node2]
>   
> +        # check if contexts are sent in reversed
> +        reversed = False
> +        if (not isinstance(ctx1, context.changectx)
> +            and isinstance(ctx2, context.changectx)):
> +            reversed = True
> +            ctx1, ctx2 = ctx2, ctx1
> +
>           working = ctx2.rev() is None
>           parentworking = working and ctx1 == self['.']
>           match = match or matchmod.always(self.root, self.getcwd())
>           listignored, listclean, listunknown = ignored, clean, unknown
>   
> @@ -1620,10 +1627,14 @@ class localrepository(object):
>                                         ' "%s"\n' % f)
>                           continue
>                   sane.append(f)
>               modified = sane
>   
> +        if reversed:
> +            added, removed = removed, added
> +            deleted, unknown = unknown, deleted
> +
>           r = modified, added, removed, deleted, unknown, ignored, clean
>   
>
This is pretty subtle.  Probably warrants in-code comments.

It also seems a little fragile (what if other people introduce other 
things that need to be reversed).  Will it still be here once all your 
patches are landed?