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Re: Integrating submodules with no side effects

From
Stefan Beller <sbeller@google.com>
Date
Oct 19, 2016, 16:23 UTC
Message-ID
<CAGZ79kYKdHHcfRxCOJwNuqnOGMjBBeMy3Av5U7_ssuOp-to61w@mail.gmail.com>
In-Reply-To
<CAHd499CN3+cHVwjOEirwXVu3DsJwPrmJwEgSJL2CHD5CvoYxxg@mail.gmail.com>
On Wed, Oct 19, 2016 at 6:27 AM, Robert Dailey <rcdailey.lists@gmail.com> wrote:
Show 73 quoted lines
> On Tue, Oct 18, 2016 at 4:17 PM, Stefan Beller <sbeller@google.com> wrote:
>> On Tue, Oct 18, 2016 at 12:35 PM, Robert Dailey
>> <rcdailey.lists@gmail.com> wrote:
>>> Hello git experts,
>>>
>>> I have in the past attempted to integrate submodules into my primary
>>> repository using the same directory name. However, this has always
>>> caused headache when going to and from branches that take you between
>>> when this integration occurred and when it didn't. It's a bit hard to
>>> explain. Basically, if I have a submodule "foo", and I delete that
>>> submodule and physically add its files under the same directory "foo",
>>> when I do a pull to get this change from another clone, it fails
>>> saying:
>>>
>>> error: The following untracked working tree files would be overwritten
>>> by checkout:
>>>         foo/somefile.txt
>>> Please move or remove them before you switch branches.
>>> Aborting
>>> could not detach HEAD
>>>
>>>
>>> Obviously, git can't delete the submodule because the files have also
>>> been added directly. I don't think it is built to handle this
>>> scenario. Here is the series of commands I ran to "integrate" the
>>> submodule (replace the submodule with a directory containing the exact
>>> contents of the submodule itself):
>>>
>>> #!/usr/bin/env bash
>>> mv "$1" "${1}_"
>>> git submodule deinit "$1"
>>
>> This removes the submodule entries from .git/config
>> (and it would remove the contents of that submodule, but they are moved)
>>
>>> git rm "$1"
>>
>> Removing the git link here.
>>
>> So we still have the entries in the .gitmodules file there.
>> Maybe add:
>>
>>     name=$(git submodule-helper name $1)
>>     git config -f .gitmodules --unset submodule.$name.*
>>     git add .gitmodules
>>
>> ? (Could be optional)
>
> Actually I verified that it seems `git rm` is specialized for
> submodules somewhere, because when I run that command on a submodule
> the relevant entries in the .gitmodules file are removed. I did not
> have to do this as a separate step.
>
>>> mv "${1}_" "$1"
>>> git add "$1/**"
>>
>> Moving back into place and adding all files in there.
>>
>>>
>>> The above script is named git-integrate-submodule, I run it like so:
>>>
>>> $ git integrate-submodule foo
>>>
>>> Then I do:
>>>
>>> $ git commit -m 'Integrated foo submodule'
>>>
>>> Is there any way to make this work nicely?
>>
>> I think you can just remove the gitlink from the index and not from the working
>> tree ("git rm --cached $1")
>
> What is the goal of doing it this way? What does this simplify?
You don't have to mv it back and forth with an underscore I would imagine?
Show 11 quoted lines
>
>>> The only solution I've
>>> found is to obviously rename the directory before adding the physical
>>> files, for example name it foo1. Because they're different, they never
>>> "clash".
>>
>> Also look at the difference between plumbing and porcelain commands[1],
>> as plumbing is more stable than the porcelain, so it will be easier to maintain
>> this script.
>
> Which plumbing commands did you have in mind?

None specifically. I write scripts using porcelain all the time for personal use. But if you were planning to publish this seriously then I'd recommend looking at plumbing commands.

Show 9 quoted lines
>
>> I think this would be an actually reasonable feature, which Git itself
>> could support via "git submodule [de]integrate", but then we'd also want
>> to see the reverse, i.e. take a sub directory and make it a submodule.
>
> Integrating this as a feature might be fine, I think when you bring up
> the question of retaining history makes things much harder.
> Fortunately for me that is not a requirement in this case, so I'm able
> to do things with much less effort.

That reminds me of subtree merging, which could be used for this case. (see 'git subtree')

Show 7 quoted lines
>
> However the primary purpose of my post was to find out how to
> integrate the submodule without the error on next pull by other
> collaborators of my repository. It's a real pain to recover your
> working copy when going inbetween commits where the submodule
> integration happened inbetween them. I did quote the exact error
> message I got in my original post.

You could try this patch series: https://github.com/jlehmann/git-submod-enhancements/tree/git-checkout-recurse-submodules (rebased to a newer version; no functional changes:) https://github.com/stefanbeller/git/tree/submodule-co (I'll rebase that later to origin/master)

Show 6 quoted lines
>
> Do you have any info on how I can prevent that error? Ideally I want
> the integration to go smoothly and transparently, not just for the
> person doing the actual transition (me) but for everyone else that
> gets those changes from upstream. They should not even notice that it
> happened (i.e. no failed commands, awkward behavior, or manual steps).

It depends on how long you want to postpone the transition, but I plan to upstream the series referenced above in the near future, which would enable your situation to Just Work (tm). ;)

Previous: Robert DaileyNext: Robert Dailey
Message 4 of 8 in “Integrating submodules with no side effects”
  1. Robert DaileyOct 18, 2016
  2. Stefan BellerOct 18, 2016
  3. Robert DaileyOct 19, 2016
  4. Stefan BellerOct 19, 2016
  5. Robert DaileyOct 19, 2016
  6. Stefan BellerOct 19, 2016
  7. Robert DaileyOct 19, 2016
  8. Robert DaileyOct 25, 2016

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