On Sun, Apr 29, 2018 at 10:53 PM, Johannes Schindelin <Johannes.Schindelin@xxxxxx> wrote: >> > @@ -1412,12 +1422,13 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options >> > WRITE_TREE_SILENT | >> > WRITE_TREE_REPAIR); >> > } >> > - move_index_extensions(&o->result, o->dst_index); >> > + move_index_extensions(&o->result, o->src_index); >> >> While this looks like the right thing to do on paper, I believe it's >> actually broken for a specific case of untracked cache. In short, >> please do not touch this line. I will send a patch to revert >> edf3b90553 (unpack-trees: preserve index extensions - 2017-05-08), >> which essentially deletes this line, with proper explanation and >> perhaps a test if I could come up with one. >> >> When we update the index, we depend on the fact that all updates must >> invalidate the right untracked cache correctly. In this unpack >> operations, we start copying entries over from src to result. Since >> 'result' (at least from the beginning) does not have an untracked >> cache, it has nothing to invalidate when we copy entries over. By the >> time we have done preparing 'result', what's recorded in src's (or >> dst's for that matter) untracked cache may or may not apply to >> 'result' index anymore. This copying only leads to more problems when >> untracked cache is used. > > Is there really no way to invalidate just individual entries? Grr.... the short answer is the current code (i.e. without Elijah's changes) works but in a twisted way. So you get to keep untracked cache in the end. I was right about the invalidation stuff. I knew about invalidate_ce_path() in this file. What I didn't remember was this function actually invalidates entries from the _source_ index, not the result one. What kind of logic is that? You copy/move entries from source to result than you go invalidate the source. Since the original move_index_extensions() call moves extensions from the source, these are already properly invalidated (both untracked cache and cache tree), it it looks like it does the right thing. Two wrongs make a right, I guess. Sorry for venting. I was not happy with what I found. And sorry for wasting your time making this move_index.. change then remove it. > I have a couple of worktrees which are *huge*. And edf3b90553 really > helped relieve the pain a bit when running `git status`. Now you say that > even a `git checkout -b new-branch` would blow the untracked cache away > again? > > It would be *really* nice if we could prevent that performance regression > somehow. > > Ciao, > Dscho -- Duy
