Re: [RFC] Clone repositories recursive with depth 1

[Stefan Beller <sbeller@google.com>]

On Wed, Nov 11, 2015 at 6:09 AM, Lars Schneider
<larsxschneider@gmail.com> wrote:
> Hi,
>
> I have a clean build machine and I want to clone my source code to this machine while transferring only the minimal necessary amount of data. Therefore I use this command:
>
> git clone --recursive --depth 1 --single-branch <url>

That *should* work, actually.
However looking at the code it does not.

citing from builtin/clone.c:

    static struct option builtin_clone_options[] = {
        ...
        OPT_BOOL(0, "recursive", &option_recursive,
           N_("initialize submodules in the clone")),
        OPT_BOOL(0, "recurse-submodules", &option_recursive,
          N_("initialize submodules in the clone")),
        ...
    };
    ...
    static const char *argv_submodule[] = {
        "submodule", "update", "--init", "--recursive", NULL
    };

    if (!err && option_recursive)
        err = run_command_v_opt(argv_submodule, RUN_GIT_CMD);

So the --depth argument is not passed on, although "git submodule update"
definitely supports --depth.

In an upcoming series (next version of origin/sb/submodule-parallel-update),
this will slightly change, such it will be even easier to add the
depth argument in
there as we construct the argument list in code instead of hard coding
argv_submodule.

This may require some discussion whether you expect --depth to be recursed.
(What if you only want a top level shallow thing?, What if you want to have only
submodules shallow? What is the user expectation here?)

>
> Apparently this does not clone the submodules with "--depth 1" (using Git 2.4.9). As a workaround I tried:
>
> git clone --depth 1 --single-branch <url>
> cd <repo-name>
> git submodule update --init --recursive --depth 1
>
> However, this does not work either as I get:
> fatal: reference is not a tree: <correct sha1 of the submodule referenced by the main project>
> Unable to checkout <correct sha1 of the submodule referenced by the main project> in submodule path <submodule path>

That seems like another bug to me.

I just tried to clone a project and populate with submodules later and
it works as expected without these error messages.
(I am running some kind of xxx.dirty development version, most likely
origin/sb/submodule-parallel-update,
I'll check some other versions, too)