Re: Git Submodules ref setting

[Philippe Blain <levraiphilippeblain@gmail.com>]

Hi, 

Le 2022-05-12 à 16:01, Вадим Цветков a écrit :
> Hello,
> 
> I've started a small project which involves several git repositories, which depends on each other.
> For dealing with these repos I wanted to use git submodules as a simple package manager.
> However, it seems impossible to lock a submodule to particular ref, only to a branch.

Submodules are recorded in the superproject *at a specific commit*.
That's the data model. There is no other options.

There is a 'branch' setting that you can put in '.gitmodules'.
This *only* affects the command 'git submodule update --remote', nothing else.

If you mean that you would like to have a non-branch ref recorded in '.gitmodules'
i.e. something like refs/other-refs/example instead of 'some-branch' that corresponds
to 'refs/heads/some-branch', then no this is not possible either.

> I would like to ask if this is deliberate design choice?

Yes, it was a deliberate design choice to have a deterministic state
of a repository using submodules upon 'git clone'. Recording a submodule
at a specific branch instead of at a specific commit would make this design
choice impossible to achieve.

> And if it's not, may I contribute this feature?
> 

It depends on what you mean by 'lock submodule to a specific ref'.

I encourage you to read the "Git Submodules" chapter of the Pro Git book [1]
for an in-depth overview of how submodules work. And after that, for reference
the Git documentation:

- git-submodule(1): https://git-scm.com/docs/git-submodule
- gitsubmodules(7): https://git-scm.com/docs/gitsubmodules
- gitmodules(5): https://git-scm.com/docs/gitmodules

I hope that helps,

Philippe.

[1] https://git-scm.com/book/en/v2/Git-Tools-Submodules