Re: [PATCH 2/3] sha1_file: add the ability to parse objects in "pack file format"

Linus Torvalds [off-list ref] writes:

Here's a newer verson of [2/3], with these issues fixed. It actually fixes 
things twice: (a) by parsing the binary version first (which makes sense 
for a totally independent reason - if that is going to be the "default" 
version in the long run, we should just test it first anyway) and (b) by 
making the ASCII version parser stricter too.

Wait a minute.

 read-sha1-file maps sha1-file-internal (for unpacked one), and then
 calls unpack-sha1-file.

 unpack-sha1-file calls unpack-sha1-header to start inflation,
 lets parse-sha1-header to read the header in the inflated
 buffer, and calls unpack-sha1-rest to inflate the rest.

But in packs, we have binary header not deflated, followed by
deflated payload.  If we want to copy things from loose objects
into pack without changing the packfile format, this change
would not help, I suspect.

At least, your updated unpack_sha1_file() needs to check for
binary header first (starting from "map"), and if that starts
with binary header, start inflating after the header to extract
the payload.  Otherwise you would do the traditional.