Re: Fwd: Re: git checkout -f branch doesn't remove extra files

Dear diary, on Sat, Aug 13, 2005 at 02:10:53PM CEST, I got a letter
where Sergey Vlasov [off-list ref] told me that...

However, cg-export is buggy - if you use the second argument
(cg-export DESTFILE TREE_ID), the resulting tar file is different
from what git-tar-tree produces for the same TREE_ID (unless that
TREE_ID actually points to a tree - but in practice a commit or even
tag ID is typically used).

The problem is in this line:

id=$(tree-id "$2")

This converts the passed commit or tag to the underlying tree, which
is then passed to git-tar-tree.  However, git-tar-tree can follow
such links itself, and, what's more important, it actually uses some
information from the passed commit (it writes the commit ID to the
tar file as an extended header, and sets timestamp of all archive
members to the time of the commit).  Therefore reducing the ID
passed to git-tar-tree to a plain tree ID is wrong - if a commit ID
is available, it should be used.

Aha! Good catch, fixed, thanks.

BTW, I also changed cg-export usage to be more consistent and flexible,
by changing it from

	cg-export DESTFILE [TREE_ID]

to

	cg-export [-r TREE_ID] DESTFILE

since I think not many people are using cg-export anyway and much less
of them passing it TREE_ID explicitly.

-- 
				Petr "Pasky" Baudis
Stuff: http://pasky.or.cz/
If you want the holes in your knowledge showing up try teaching
someone.  -- Alan Cox