Re: What's cooking in git.git (Jul 2017, #01; Wed, 5)

From: Stefan Beller <sbeller@google.com>
Date: Jul 10, 2017, 17:27 UTC
Message-ID: <CAGZ79kZMC4DcnF-6nT49uZT8NtiWWkKyUm44BHRBPt98idj_Pw@mail.gmail.com>
In-Reply-To: <xmqqbmoxdmea.fsf@gitster.mtv.corp.google.com>

On Thu, Jul 6, 2017 at 7:13 PM, Junio C Hamano <gitster@pobox.com> wrote:

Show 13 quoted lines

> Stefan Beller <sbeller@google.com> writes:
>
>> Speaking of submodules, It's not just features, but I also send bug fixes. ;)
>> https://public-inbox.org/git/20170630003851.17288-1-sbeller@google.com/
>> (That patch is not related to this series, except for working in the submodule
>> area, but I consider that patch more important than e.g. this series.)
>
> I did not see the patch as fixing a bug, though.
>
> I do agree that overwriting the branch tips in the submodule
> repositories, possibly rewinding and discarding user's work done on
> the local branches, is indeed a problem.  It however is unclear why
> detaching HEAD is a good solution to solve that problem.

I am not saying detaching a HEAD is a good solution, but I am saying it is a better solution than corrupting the submodule branch, such that commits are lost in the submodule, only to be recorvered via the reflog.

Show 10 quoted lines

> After all, there must have been a reason why the user had checked
> out a branch and had pointed it at a specific commit (presumably,
> so that further work would be done while on the branch, to make it
> easier and safer to eventually push the result back to the upstream
> of the submodule's project).  So another solution that seems equally
> viable, if not even more so, could be to fail the recursive checkout
> saying why the checkout cannot be done, just like we fail a checkout
> when a local change interferes with updating the contents in the
> working tree and the index with an error message explaining which
> paths are problematic.

That seems like a better model to me for now.

> I am *not* saying which one among the above two is better; I am not
> even saying that there could be only these two possible solutions.
> I just found the posted patch unsatisfactory because it did not make
> it clear why the chosen solution is a good one.

ok. My long term plan is to introduce another type of symbolic ref, which references a gitlink in another repository, such that the submodule can have a clear distinction between "follows the superproject", "has its own authoritative branch" and "its detached HEAD can mean anything, e.g. historical submodule behavior"

> Perhaps I misread the description; but that would mean the
> description was prone to be misread and has room for improvement ;-)

ok.