On Thu, 21 Feb 2019 04:27:21 -0500 Eric Sunshine <sunshine@xxxxxxxxxxxxxx> wrote: > On Wed, Feb 20, 2019 at 1:35 PM Eric Sunshine <sunshine@xxxxxxxxxxxxxx> wrote: > > On Wed, Feb 20, 2019 at 12:16 PM Michal Suchánek <msuchanek@xxxxxxx> wrote: > > > On Wed, 20 Feb 2019 11:55:46 -0500 > > > Eric Sunshine <sunshine@xxxxxxxxxxxxxx> wrote: > > > > On Wed, Feb 20, 2019 at 11:17 AM Michal Suchanek <msuchanek@xxxxxxx> wrote: > > > > > Another even rarer issue is that the file might be zero size because another > > > > > process initializing a worktree opened the file but has not written is content > > > > > yet. > > > > > > > > Based upon the explanation thus far, I'm having trouble understanding > > > > under what circumstances these race conditions can arise. Are you > > > > trying to invoke Git commands in a particular worktree even as the > > > > worktree itself is being created? > > > > > > It's explained in the following paragraph. If you have multiple > > > worktrees some *other* worktreee may be uninitialized. > > > > I understand that, but setup.c:get_common_dir_noenv() is concerned > > only with _this_ worktree -- the one in which the Git command is being > > run -- so it's not clear if or how some other partially-initialized > > worktree could have any impact. (And, I'm having trouble fathoming how > > it could, which is why I'm asking these questions). > > I still can't see how setup.c:get_common_dir_noenv() could be > responsible for the behavior you're describing of _any_ Git command > erroring out due to _any_ worktree being incompletely-initialized. > However, I can imagine "git worktree add" itself being racy and > failing due to a missing or empty "commondir" file for some other > worktree since that command _does_ consult other worktree entries when > validating the "add" operation via > builtin/worktree.c:validate_worktree_add() which calls > get_worktrees(). If get_worktrees() is subject to that raciness > problem, then "git worktree add" will inherit that undesirable > raciness behavior (as will other "git worktree" commands which call > get_worktrees(), such as "git worktree list"). > > > Is it possible that when you saw that error message, it actually arose > > from some code other than setup.c:get_common_dir_noenv()? > > So, I'm suspecting get_worktrincludes both itees() or some function it calls (and so > on) as the racy culprit. Yes, that's my explanation for the situation as well. Thanks Michal
