[RFC PATCH 0/8] Get rid of "git --super-prefix"

An RFC alternative to Glen's [1], and what I *thought* he might be be going for in the earlier discussion[2].

The difference is that in Glen's there's no "git --super-prefix", but rather each set of commands still using it ("submodule--helper", "read-tree" etc.) geit their own command-level option.

But it still works substantially the same, in that we're juggling a global variable that we set, and read out later somewhere down the stack.

Whereas here there's no renaming of the option, but:

 * For "submodule--helper" only the sub-commands that need it take the
   option, it's not an option to "submodule--helper" itself.

 * There's no passing of the "super_prefix" as a global, instead we
   pass it all the way along until we recurse to ourselves. For
   "submodule--helper" this is quite straightforward.

 * Then in 8/8 we're left with just "read-tree" needing the remaining
   "--super-prefix", and we likewise don't pass it as a global, but
   instead add it to the "struct unpack_trees_options", which will
   pass it all the way down into unpack-trees.c and entry.c, until
   we're going to recursively invoke another "read-tree".

This is on top of my "ab/submodule-helper-prep-only" which is now in "next", and can make use of (but doesn't need) the better test coverage for "absorbgitdirs" that I submitted in [3].

A non-RFC version of this should really steal Glen's tests, in particular the "partial clone" one from [4]. That test passes with this series.

1. https://lore.kernel.org/git/20221109004708.97668-1-chooglen@google.com/
2. https://lore.kernel.org/git/kl6l8rkqy7no.fsf@chooglen-macbookpro.roam.corp.google.com/
3. https://lore.kernel.org/git/patch-1.1-34b54fdd9bb-20221109T020347Z-avarab@gmail.com/
4. https://lore.kernel.org/git/20221109004708.97668-4-chooglen@google.com/.

Ævar Arnfjörð Bjarmason (8):
  submodule--helper: don't use global --super-prefix in "absorbgitdirs"
  submodule--helper: "deinit" has never used "--super-prefix"
  submodule--helper: convert "foreach" to its own "--super-prefix"
  submodule--helper: convert "sync" to its own "--super-prefix"
  submodule--helper: convert "status" to its own "--super-prefix"
  submodule--helper: convert "{update,clone}" to their own
    "--super-prefix"
  submodule tests: test "git branch -t" output and stderr
  read-tree: add "--super-prefix" option, eliminate global

 Documentation/git.txt       |  8 +--
 builtin.h                   |  4 --
 builtin/checkout.c          |  2 +-
 builtin/read-tree.c         |  1 +
 builtin/submodule--helper.c | 95 ++++++++++++++++++++---------------
 cache.h                     |  2 -
 entry.c                     | 12 ++---
 entry.h                     |  6 ++-
 environment.c               | 13 -----
 git.c                       | 37 ++------------
 parse-options.h             |  4 ++
 submodule.c                 | 47 ++++++++----------
 submodule.h                 | 12 +++--
 t/lib-submodule-update.sh   | 98 +++++++++++++++++++++----------------
 t/t1001-read-tree-m-2way.sh |  2 +-
 unpack-trees.c              | 23 +++++----
 unpack-trees.h              |  1 +
 17 files changed, 177 insertions(+), 190 deletions(-)