[PATCH 2 of 3] lfs: prefetch lfs blobs when applying merge updates

[Yuya Nishihara]

On Sun, 04 Feb 2018 01:18:24 -0500, Matt Harbison wrote:
> # HG changeset patch
> # User Matt Harbison <matt_harbison at yahoo.com>
> # Date 1517711172 18000
> #      Sat Feb 03 21:26:12 2018 -0500
> # Node ID e779b0c34d6989e45cabbf8da8cdfeb060134dbd
> # Parent  359c61b92d8b47b866a8b527829643f45bba8970
> lfs: prefetch lfs blobs when applying merge updates

Seems good, but a couple of nits.

> --- a/hgext/lfs/wrapper.py
> +++ b/hgext/lfs/wrapper.py
> @@ -249,6 +249,34 @@
>      if 'lfs' in destrepo.requirements:
>          destrepo.vfs.append('hgrc', util.tonativeeol('\n[extensions]\nlfs=\n'))
>  
> +def mergemodapplyupdates(orig, repo, actions, wctx, mctx, overwrite, labels):

Nit: labels=None for API compatibility.

> +    """Ensure that the required LFS blobs are present before applying updates,
> +    fetching them as a group if needed.
> +
> +    This has the effect of ensuring all necessary LFS blobs are present before
> +    making working directory changes during an update (including after clone and
> +    share) or merge."""
> +
> +    pointers = []
> +    localstore = repo.svfs.lfslocalblobstore
> +
> +    # Skipping 'a', 'am', 'f', 'r', 'dm', 'e', 'k', 'p' and 'pr', because they
> +    # don't touch mctx.  'cd' is skipped, because changed/deleted never resolves
> +    # to something from the remote side.
> +    for a in 'g dc dg m'.split():
> +        l = actions[a]
> +        if len(l) > 0:

Any reason to test the length here?

> +            for f, msg, args in l:
                   ^^^^^^^^^^^^
                   f, args, msg

> +                p = pointerfromctx(mctx, f)
> +                if p and not localstore.has(p.oid()):
> +                    p.filename = f
> +                    pointers.append(p)
> +
> +    if pointers:
> +        repo.svfs.lfsremoteblobstore.readbatch(pointers, localstore)
> +
> +    return orig(repo, actions, wctx, mctx, overwrite, labels)