Re: [PATCH 00/16] worktree: use "git reset --hard" to populate worktree

> Eric Sunshine <sunshine@sunshineco.com> writes:
> 
>> This is a follow-on series to [1], which migrated "git checkout --to"
>> functionality to "git worktree add". That series continued using "git
>> checkout" for the initial population of the new worktree, which required
>> git-checkout to have too intimate knowledge that it was operating in a
>> newly created worktree.
>>
>> This series eliminates git-checkout from the picture by instead
>> employing "git reset --hard"[2] to populate the new worktree initially.
>>
>> It is built atop 1eb07d8 (worktree: add: auto-vivify new branch when
>> <branch> is omitted, 2015-07-06), currently in 'next', which is
>> es/worktree-add except for the final patch (which retires
>> --ignore-other-worktrees) since the intention[3] was to drop that patch.
> 
> A few comments on things I noticed while reading (mostly coming from
> the original before this patch series):
> 
>  - What does this comment apply to?
> 
>         /*
>          * $GIT_COMMON_DIR/HEAD is practically outside
>          * $GIT_DIR so resolve_ref_unsafe() won't work (it
>          * uses git_path). Parse the ref ourselves.
>          */
> 
>    It appears in front of a call to check-linked-checkout, but I
>    think the comment attempts to explain why it manually decides
>    what the path should be in that function, so perhaps move it to
>    the callee from the caller?
> 
>  - check_linked_checkout() when trying to decide what branch is
>    checked out assumes HEAD is always a regular file, but I do not
>    think we have dropped the support of SYMLINK_HEAD yet.  It needs
>    to check st_mode and readlink(2), like resolve_ref_unsafe() does.
> 
>  - After a new skelton worktree is set up, the code runs a few
>    commands to finish populating it, under a different pair of
>    GIT_DIR/GIT_WORK_TREE, but the function does so with setenv(); it
>    may be cleaner to use cp.env[] for it, as the process we care
>    about using the updated environment is not "worktree add" command
>    we are running ourselves, but "update-ref/symbolic-ref" and
>    "reset" commands that run in the new worktree.
> 
> Other than that, looks nicely done.
> 
> I however have to wonder if the stress on "reset --hard" on log
> messages of various commits (and in the endgame) is somewhat
> misplaced.
> 
> The primary thing we wanted to see, which this series nicely brings
> us, is to remove "new-worktree-mode" hack from "checkout" (in other
> words, instead of "reset --hard", "checkout -f" would also have been
> a satisfactory endgame).
> 
> Thanks.
>