[PATCH] revset: add the 'subrev' symbol

[Pierre-Yves David]

On 06/24/2015 02:55 PM, Matt Harbison wrote:
> # HG changeset patch
> # User Matt Harbison <matt_harbison at yahoo.com>
> # Date 1435179910 14400
> #      Wed Jun 24 17:05:10 2015 -0400
> # Node ID 74b79bc0f22824f1858750f987915671e3ecf1b9
> # Parent  1de5b35cecd32a4691d0542d03348c13e5813c95
> revset: add the 'subrev' symbol
>
> This finds revisions in the outer repo that track a named revision of a subrepo.
> It allows for a partial match, as long as the named revision is at least as long
> as the 'shortid' form defined by the subrepo.  Allowing shorter strings seems
> risky- the user may specify a "{rev}" value, and not realize it only partially
> matches on a full "{node}".
>
> A more general query is to figure out what revisions in the outer repo track the
> named revision, _or a descendant of it_.  This would make it much easier to
> figure out where a subrepo change becomes visible if there are a series of
> subrepo changes, with one lockin commit to the outer repo.  But that looks much
> more complicated.  If that makes sense to implement in this revset in the
> future, we can probably do so by adding an argument to the revset that controls
> the behavior, similar to the -key arg to sort().

What I would expect from such feature is

   hg log --rev 'subrepo([pattern], revs="anyrevset")'

1) This would allow to select the subrepo we are targeting (which have 
usability and performance benefit).

2) having revset would allow any kind of operation (including revision X 
or descendant to be done).

Doing (1) seems simple. Doing (2) is a bit tricker because as far as I 
know, the subrepo is not necessarly checked out. So we should maybe 
design the API so it could support any revsets but only support hex-node 
for now.
We can probably use revset now if the repo is checkout in the repository 
or if the subrepo cache is operational. But supporting (2) seems a bit 
premature(as this changeset already points).

What do you think about (1) (reusing the subrepo revset?

-- 
Pierre-Yves David