[PATCH] memctx: fix memctx manifest file hashes

[Sean Farley]

Durham Goode <durham at fb.com> writes:

> # HG changeset patch
> # User Durham Goode <durham at fb.com>
> # Date 1454550251 28800
> #      Wed Feb 03 17:44:11 2016 -0800
> # Node ID 5211c5eee88649263624a82e65dc53e6f3882ba3
> # Parent  01a5143cd25f285f8c745a92986cd7186bb32c90
> memctx: fix memctx manifest file hashes
>
> When memctx is asked for a manifest, it constructs one by merging the p1
> manifest, and the changes that are on top. For the changes on top, it was
> previously using p1.node() as the file entries parent, which actually returns
> the commit node that the p1 linkrev points at! Which is entirely incorrect.
>
> The fix is to use p1.filenode() instead, which returns the parent file node as
> desired.
>
> I don't know how to execute this or make it have a visible effect, so I'm not
> sure how to test it.  It was noticed because asking for the linkrev is an
> expensive operation when using the remotefilelog extension and this was causing
> performance regressions with commit.

Huh. This is almost certainly my fault for misunderstanding node vs
filenode. I just ran this patch against our internal memctx at Bitbucket
and it passed this change seems fine to me.