Re: [PATCH 00/23] Preliminary pack v4 support

On Wed, 28 Aug 2013, Duy Nguyen wrote:

On Tue, Aug 27, 2013 at 11:44 PM, Junio C Hamano [off-list ref] wrote:

quoted

As you have "0-index" escape hatch for SHA-1 table, but no similar
escape hatch for the people's name table, I can see why it may be
cumbersome to fix a thin pack by only appending to a received
packfile and updating a few header fields, though.

We also need an escape hatch for path name table.

Well, right. I think this is probably the cleanest solution if we don't 
want to update the commit/tree dictionary table with new entries (they 
could simply be appended at the end).  That wouldn't work for the SHA1 
table though, so perhaps a secondary table for the appended objects 
could then be carried into the pack index file.

But what if we store
appended objects in OBJ_REF_DELTA format where base ref is empty
tree/commit and cached by sha1_file.c?

I don't follow you here.  Missing objects need to be added to the pack, 
they can't be cached anywhere.

We won't need to update
dictionary tables. Parsing is a bit ugly though (e.g. v3 tree with v2
base) but we have to deal with that anyway because people can have v2
and v3 packs mixed in.

Absolutely.


Nicolas