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From: Eric Sunshine <sunshine@sunshineco.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Git List <git@vger.kernel.org>, Duy Nguyen <pclouds@gmail.com>,
	Mark Levedahl <mlevedahl@gmail.com>,
	Mikael Magnusson <mikachu@gmail.com>
Subject: Re: [PATCH 00/16] worktree: use "git reset --hard" to populate worktree
Date: Wed, 15 Jul 2015 02:48:17 -0400	[thread overview]
Message-ID: <CAPig+cTXAdGFmq+QkNAgmHJuZgM6-Ckg_-StrTQUxmJSpX4=Qg@mail.gmail.com> (raw)
In-Reply-To: <xmqqsi8rzyzo.fsf@gitster.dls.corp.google.com>

On Mon, Jul 13, 2015 at 2:36 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Eric Sunshine <sunshine@sunshineco.com> writes:
>> This series eliminates git-checkout from the picture by instead
>> employing "git reset --hard"[2] to populate the new worktree initially.
>
> 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?

The placement of the comment in the original code wasn't bad, but
after patch 3/16 moves code around, the comment does become somewhat
confusing, so moving it to the callee seems a reasonable idea.

>  - 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.

Hmm, I wasn't aware of SYMLINK_HEAD (and don't know if Duy was). The
related code in resolve_ref_unsafe() is fairly involved, worrying
about race conditions and such, however, I guess
check_linked_checkout()'s implementation can perhaps be simpler, as
it's probably far less catastrophic for it to give the wrong answer
(or just die) under such a race?

>  - 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.

After sending the series, I was realized that this could be done more
cleanly with -C, but that would have to be repeated for each command,
so cp.env[] might indeed be a better choice.

> 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).

I'll see if the commit messages can be reworded a bit without becoming
too wordy. ("git reset --hard" has a nice conciseness.)

  parent reply	other threads:[~2015-07-15  6:48 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-11  0:05 [PATCH 00/16] worktree: use "git reset --hard" to populate worktree Eric Sunshine
2015-07-11  0:05 ` [PATCH 01/16] checkout: avoid resolving HEAD unnecessarily Eric Sunshine
2015-07-11  0:05 ` [PATCH 02/16] checkout: name check_linked_checkouts() more meaningfully Eric Sunshine
2015-07-11  0:05 ` [PATCH 03/16] checkout: improve die_if_checked_out() robustness Eric Sunshine
2015-07-11  0:05 ` [PATCH 04/16] checkout: die_if_checked_out: simplify strbuf management Eric Sunshine
2015-07-11  0:05 ` [PATCH 05/16] checkout: generalize die_if_checked_out() branch name argument Eric Sunshine
2015-07-11  0:05 ` [PATCH 06/16] branch: publish die_if_checked_out() Eric Sunshine
2015-07-11  0:05 ` [PATCH 07/16] worktree: simplify new branch (-b/-B) option checking Eric Sunshine
2015-07-11  0:05 ` [PATCH 08/16] worktree: introduce options container Eric Sunshine
2015-07-11  0:05 ` [PATCH 09/16] worktree: make --detach mutually exclusive with -b/-B Eric Sunshine
2015-07-11  0:05 ` [PATCH 10/16] worktree: make branch creation distinct from worktree population Eric Sunshine
2015-07-12  1:20   ` Duy Nguyen
2015-07-12  2:36     ` Eric Sunshine
2015-07-12  2:48       ` Duy Nguyen
2015-07-12  3:10         ` Eric Sunshine
2015-07-12  3:14           ` Eric Sunshine
2015-07-12  3:27             ` Eric Sunshine
2015-07-12 10:03               ` Duy Nguyen
     [not found]               ` <CACsJy8BTTdWrCZNz=y686pgju5X8-2mPrNNQ-+z4ByeKD6O5Uw@mail.gmail.com>
2015-07-12 19:20                 ` Eric Sunshine
2015-07-11  0:05 ` [PATCH 11/16] worktree: add_worktree: construct worktree-population command locally Eric Sunshine
2015-07-11  0:05 ` [PATCH 12/16] worktree: detect branch symref/detach and error conditions locally Eric Sunshine
2015-07-11  0:05 ` [PATCH 13/16] worktree: make setup of new HEAD distinct from worktree population Eric Sunshine
2015-07-11  0:05 ` [PATCH 14/16] worktree: avoid resolving HEAD unnecessarily Eric Sunshine
2015-07-11  0:05 ` [PATCH 15/16] worktree: populate via "git reset --hard" rather than "git checkout" Eric Sunshine
2015-07-11  0:05 ` [PATCH 16/16] checkout: drop intimate knowledge of new worktree initial population Eric Sunshine
2015-07-13 18:36 ` [PATCH 00/16] worktree: use "git reset --hard" to populate worktree Junio C Hamano
2015-07-14  9:53   ` Michael J Gruber
2015-07-14 10:09     ` Duy Nguyen
2015-07-14 16:40     ` Eric Sunshine
2015-07-15  6:48   ` Eric Sunshine [this message]
2015-07-15  9:59     ` Duy Nguyen

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