The mechanism to register in-memory alternate object sources has
been removed, as submodule object databases are now accessed
natively via their own repository structures. This simplifies
object database management and prepares the codebase for migrating
alternate tracking into the files backend.
* ps/odb-stop-registering-in-memory-sources:
odb: remove the ability to link sources ad-hoc
t/helper: stop registering alternates in "ref-store" command
t/helper: adapt read-midx to not link ad-hoc source anymore
builtin/multi-pack-index: refuse unknown sources with "--object-dir="
odb/packed: fix memory leaks when freeing source
tmp-objdir: drop unused function to register alternate
odb: remove infrastructure to register submodule sources
builtin/grep: stop registering submodule ODB as source
submodule-config: stop registering submodule sources
submodule-config: stop using `the_hash_algo`
submodule-config: remove uses of `the_repository`
cache-tree: remove dependency on `the_repository`
cache-tree: drop `the_repository` in `cache_tree_fully_valid()`
4ee3b87aaa