Re: [PATCH] fast-import: Allow filemodify to set the root

[Jonathan Nieder <jrnieder@gmail.com>]

Johannes Sixt wrote:
> Am 10/7/2010 22:28, schrieb Jonathan Nieder:

>> | For a command (like filter-branch --subdirectory-filter) that wants
>> | to commit a lot of trees that already exist in the object db, writing
>> | undeltified objects as loose files only to repack them later can
>> | involve a significant amount[*] of overhead.
>
> 1. But when an object already exists in the db, it won't be written again,
> will it?

In David's application, the trees already exist, but the commits are new.

> 2. Even though fast-import puts all (new) objects into a pack file, the
> pack is heavily sub-optimal, and you should repack -f anyway. So what's
> the point? Only to avoid a loose object?

To avoid thousands of loose objects.

> (I'm not saying that the patch is unwanted, but only that the
> justification is still not sufficiently complete.)

No problem - these questions are useful.  If the result is learning
that something else is responsible for the speedup David observed in
his script, that would not be a bad outcome after all.

I suppose supporting M 040000 <tree> "" and C <path> "" could still
be a good idea in that case anyway, for the convenience of front-end
authors.

Jonathan
who still hasn't reviewed the patch (sorry)