Scenario: clone-from-submodule, without a branch

The submodule names no branch in .gitmodules, as in the parent scenario: it stays at its commit until someone moves it. The splice stays too: default-pin pins that commit (default-pin).

Monorepo, on main: vendor/a/ is a submodule of the upstream, checked out at seed.
Upstream ($UPSTREAM, reached as https://git.example.com/a.git): seed, then newer on main.

Output

setup.bash builds this state:

$ build_scenario scenario_submodule_without_branch https://git.example.com/a.git

$ git splice clone --from-submodule vendor/a
===  vendor/a: fetching https://git.example.com/a.git
ok   vendor/a: cloned bde4164 from the submodule
===  vendor/a: pinned at bde4164, as the submodule was -- pull brings in nothing and push refuses on main until it follows a branch: git config --file vendor/a/.splice --unset upstream.origin.default-pin
===  vendor/a: the submodule's repository stays in .*/monorepo/\.git/modules/vendor/a -- remove it once you don't need it (regex)

$ cat vendor/a/.splice
[splice]
	id = e4779bec163bd89d
	commit = bde416459fbcc09c9b585f3b65a94cab3f68bfcd
[upstream "origin"]
	url = https://git.example.com/a.git
	default-pin = bde416459fbcc09c9b585f3b65a94cab3f68bfcd

The upstream's newer doesn't count: main syncs with the pinned commit, which the splice matches.

$ git splice status
On branch main

  up to date  vendor/a -> bde4164

To follow main instead, remove the pin and commit that:

$ git config --file vendor/a/.splice --unset upstream.origin.default-pin &&
>   git commit -q -m "vendor/a: follow main" vendor/a/.splice

Now newer is there to pull:

$ git splice status
On branch main

  behind 1  vendor/a

Output​

Output