We're currently creating the reference database with a potentially
incorrect object format when the remote repository's object format is
different from the local default object format. This works just fine for
now because the files backend never records the object format anywhere.
But this logic will fail with any new reference backend that encodes
this information in some form either on-disk or in-memory.
The preceding commits have reshuffled code in git-clone(1) so that there
is no code path that will access the reference database before we have
detected the remote's object format. With these refactorings we can now
defer initialization of the reference database until after we have
learned the remote's object format and thus initialize it with the
correct format from the get-go.
These refactorings are required to make git-clone(1) work with the
upcoming reftable backend when cloning repositories with the SHA256
object format.
This change breaks a test in "t5550-http-fetch-dumb.sh" when cloning an
empty repository with `GIT_TEST_DEFAULT_HASH=sha256`. The test expects
the resulting hash format of the empty cloned repository to match the
default hash, but now we always end up with a sha1 repository. The
problem is that for dumb HTTP fetches, we have no easy way to figure out
the remote's hash function except for deriving it based on the hash
length of refs in `info/refs`. But as the remote repository is empty we
cannot rely on this detection mechanism.
Before the change in this commit we already initialized the repository
with the default hash function and then left it as-is. With this patch
we always use the hash function detected via the remote, where we fall
back to "sha1" in case we cannot detect it.
Neither the old nor the new behaviour are correct as we second-guess the
remote hash function in both cases. But given that this is a rather
unlikely edge case (we use the dumb HTTP protocol, the remote repository
uses SHA256 and the remote repository is empty), let's simply adapt the
test to assert the new behaviour. If we want to properly address this
edge case in the future we will have to extend the dumb HTTP protocol so
that we can properly detect the hash function for empty repositories.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow callers to skip creation of the reference database via a new flag
`INIT_DB_SKIP_REFDB`, which is required for git-clone(1) so that we can
create it at a later point once the object format has been discovered
from the remote repository.
Note that we also uplift the call to `create_reference_database()` into
`init_db()`, which makes it easier to handle the new flag for us. This
changes the order in which we do initialization so that we now set up
the Git configuration before we create the reference database. In
practice this move should not result in any change in behaviour.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are many reasons why discovering a Git directory may fail. In
particular, 8959555cee (setup_git_directory(): add an owner check for
the top-level directory, 2022-03-02) added ownership checks as a
security precaution.
Callers attempting to set up a Git directory may want to inform the user
about the reason for the failure. For that, expose the enum
discovery_result from within setup.c and move it into cache.h where
discover_git_directory() is defined.
I initially wanted to change the return type of discover_git_directory()
to be this enum, but several callers rely upon the "zero means success".
The two problems with this are:
1. The zero value of the enum is actually GIT_DIR_NONE, so nonpositive
results are errors.
2. There are multiple successful states; positive results are
successful.
It is worth noting that GIT_DIR_NONE is not returned, so we remove this
option from the enum. We must be careful to keep the successful reasons
as positive values, so they are given explicit positive values.
Instead of updating all callers immediately, add a new method,
discover_git_directory_reason(), and convert discover_git_directory() to
be a thin shim on top of it.
One thing that is important to note is that discover_git_directory()
previously returned -1 on error, so let's continue that into the future.
There is only one caller (in scalar.c) that depends on that signedness
instead of a non-zero check, so clean that up, too.
Because there are extra checks that discover_git_directory_reason() does
after setup_git_directory_gently_1(), there are other modes that can be
returned for failure states. Add these modes to the enum, but be sure to
explicitly add them as BUG() states in the switch of
setup_git_directory_gently().
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The functions init_db() and initialize_repository_version() were shared
by builtin/init-db.c and builtin/clone.c, and declared in cache.h.
Move these functions, plus their several helpers only used by these
functions, to setup.[ch].
Diff best viewed with `--color-moved`.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
