Re: git bugs

On Tue, 10 Jun 2008, Ben Lynn wrote:

Am I going crazy? All of a sudden I think I can get away without a
size zero hack. How about this smudging routine:

if (!ce_match_stat_basic(ce, &st)) {
  recompute_sha1_and_update_index();  // no other checks required
}

No.

You can't recompute the sha1. That SHA1 is what the user asked us to 
remember - whether smudged or not. So you mustn't change it, until the 
user does a "git add" or "git update-index" (or anything that implicitly 
does the same).

You can change the _stat_ information, since that is only used for 
matching the tree (positively or negatively), but the SHA1 itself is not 
just a cache, it's the "pending state" in the index.

So smudging must change some piece of data that is only about the stat 
cache - the st_size, the mtime, anything like that.

			Linus