As reported in https://github.com/git-for-windows/git/issues/3688, calling
git fetch -h outside a repository now results in a very ugly

 BUG: repo-settings.c:23: Cannot add settings for uninitialized repository

The reason is that the prepare_repo_settings() calls (that we introduced to
support sparse index) assume that there is a gitdir, but the hack to allow
parse_options() to handle -h even outside a repository invalidates that
assumption.

One strategy I considered was to move the prepare_repo_settings() calls
after parse_options(). This would work because when parse_options() handles
-h, it exits without returning.

However, this strategy failed in my tests because e.g. cmd_unpack_objects()
does need the pack_use_sparse to be populated correctly before even parsing
the options so that it can be overridden via --sparse/--no-sparse.

Hence the current strategy where the code that prepares the repo settings
and then accesses them is guarded behind the condition that we must have a
gitdir to do so.

Note: There are other instances where prepare_repo_settings() is called
before parse_options(), e.g. in cmd_status(), in seen there are even more
instances (e.g. cmd_checkout_index()). All of those instances that are not
touched by this here patch do have special code to handle -h early, though,
before calling prepare_repo_settings() let alone parse_options().

Johannes Schindelin (2):
  checkout/fetch/pull/pack-objects: allow `-h` outside a repository
  t0012: verify that built-ins handle `-h` even without gitdir

 builtin/checkout.c     | 7 ++++---
 builtin/fetch.c        | 6 ++++--
 builtin/pack-objects.c | 8 +++++---
 builtin/pull.c         | 6 ++++--
 t/t0012-help.sh        | 7 ++++++-
 5 files changed, 23 insertions(+), 11 deletions(-)

base-commit: 4c53a8c20f8984adb226293a3ffd7b88c3f4ac1a

Submitted-As: https://lore.kernel.org/git/pull.1139.v2.git.1644319314.gitgitgadget@gmail.com
In-Reply-To: https://lore.kernel.org/git/pull.1139.git.1644277797.gitgitgadget@gmail.com