Re: [PATCH 2/2] setup: don't fail if commondir reference is deleted.

On Thu, Feb 21, 2019 at 8:50 PM Michal Suchánek [off-list ref] wrote:

On Thu, 21 Feb 2019 17:50:38 +0700
Duy Nguyen [off-list ref] wrote:

quoted

On Tue, Feb 19, 2019 at 12:05 AM Michal Suchanek [off-list ref] wrote:

quoted

When adding wotktrees git can die in get_common_dir_noenv while
examining existing worktrees because the commondir file does not exist.
Rather than testing if the file exists before reading it handle ENOENT.

I don't think we could go around fixing every access to incomplete
worktrees like this. If this is because of racy 'worktree add', then
perhaps a better solution is make it absolutely clear it's not ready
for anybody to access.

For example, we can suffix the worktree directory name with ".lock"
and make sure get_worktrees() ignores entries ending with ".lock".
That should protect other commands while 'worktree add' is still
running. Only when the worktree is complete that 'worktree add' should
rename the directory to lose ".lock" and run external commands like
git-checkout to populate the worktree.

The problem is we don't forbid worktree names ending with ".lock".
Which means that if we start to forbid them now existing worktrees
might become inaccessible.

Worktrees ending with .lock will not work well now anyway. While [1]
reports the problem with worktree names having a whitespace, ".lock"
is in the same class (not a valid refname) and will result the same
error. So if you have "*.lock" worktrees now you're already in
trouble.

[1] https://public-inbox.org/git/1550673274.30738.0@yandex.ru/T/#m9d86e0a388fd4961bc102c2c69e8bc3b2db07a42
-- 
Duy