builtin/refs: new command to migrate ref storage formats

Introduce a new command that allows the user to migrate a repository
between ref storage formats. This new command is implemented as part of
a new git-refs(1) executable. This is due to two reasons:

  - There is no good place to put the migration logic in existing
    commands. git-maintenance(1) felt unwieldy, and git-pack-refs(1) is
    not the correct place to put it, either.

  - I had it in my mind to create a new low-level command for accessing
    refs for quite a while already. git-refs(1) is that command and can
    over time grow more functionality relating to refs. This should help
    discoverability by consolidating low-level access to refs into a
    single executable.

As mentioned in the preceding commit that introduces the ref storage
format migration logic, the new `git refs migrate` command still has a
bunch of restrictions. These restrictions are documented accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/builtin.h b/builtin.h
index 28280636da..7eda9b2486 100644
--- a/builtin.h
+++ b/builtin.h
@@ -207,6 +207,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix);
 int cmd_rebase__interactive(int argc, const char **argv, const char *prefix);
 int cmd_receive_pack(int argc, const char **argv, const char *prefix);
 int cmd_reflog(int argc, const char **argv, const char *prefix);
+int cmd_refs(int argc, const char **argv, const char *prefix);
 int cmd_remote(int argc, const char **argv, const char *prefix);
 int cmd_remote_ext(int argc, const char **argv, const char *prefix);
 int cmd_remote_fd(int argc, const char **argv, const char *prefix);