When performing a fetch with an object filter, we mark the resulting
packfile as a promisor pack. An object part of such a pack may miss any
of its referenced objects, and Git knows to handle this case by fetching
any such missing objects from the promisor remote.
The "promisor" property needs to be retained going forward. So every
time we pack a promisor object, the resulting pack must be marked as a
promisor pack. git-repack(1) does this already: when a repository has a
promisor remote, it knows to pass "--exclude-promisor-objects" to the
git-pack-objects(1) child process. Promisor packs are written separately
when doing an all-into-one repack via `repack_promisor_objects()`.
But we don't support promisor objects when doing a geometric repack yet.
Promisor packs do not get any special treatment there, as we simply
merge promisor and non-promisor packs. The resulting pack is not even
marked as a promisor pack, which essentially corrupts the repository.
This corruption couldn't happen in the real world though: we pass both
"--exclude-promisor-objects" and "--stdin-packs" to git-pack-objects(1)
if a repository has a promisor remote, but as those options are mutually
exclusive we always end up dying. And while we made those flags
compatible with one another in a preceding commit, we still end up dying
in case git-pack-objects(1) is asked to repack a promisor pack.
There's multiple ways to fix this:
- We can exclude promisor packs from the geometric progression
altogether. This would have the consequence that we never repack
promisor packs at all. But in a partial clone it is quite likely
that the user generates a bunch of promisor packs over time, as
every backfill fetch would create another one. So this doesn't
really feel like a sensible option.
- We can adapt git-pack-objects(1) to support repacking promisor packs
and include them in the normal geometric progression. But this would
mean that the set of promisor objects expands over time as the packs
are merged with normal packs.
- We can use a separate geometric progression to repack promisor
packs.
The first two options both have significant downsides, so they aren't
really feasible. But the third option fixes both of these downsides: we
make sure that promisor packs get merged, and at the same time we never
expand the set of promisor objects beyond the set of objects that are
already marked as promisor objects.
Implement this strategy so that geometric repacking works in partial
clones.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We're about to add a second caller that wants to remove redundant packs
after a geometric repack. Split out the function which does this to
prepare for that.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We're about to add a second caller that wants to compute the repacking
split for a set of packfiles. Split out the function that computes this
split to prepare for that.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We have a bunch of different sites that want to iterate through all
packs of a given `struct packfile_store`. This pattern is somewhat
verbose and repetitive, which makes it somewhat cumbersome.
Introduce a new macro `repo_for_each_pack()` that removes some of the
boilerplate.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "pack_kept_objects" variable is defined as static to the repack
builtin, but is inherently related to the pack-objects arguments that
the builtin uses when generating new packs.
Move that field into the "struct pack_objects_args", and shuffle around
where we append the corresponding command-line option when preparing a
pack-objects process. Specifically:
- `write_cruft_pack()` always wants to pass "--honor-pack-keep", so
explicitly set the `pack_kept_objects` field to "0" when initializing
the `write_pack_opts` struct before calling `write_cruft_pack()`.
- `write_filtered_pack()` no longer needs to handle writing the
command-line option "--honor-pack-keep" when preparing a pack-objects
process, since its call to `prepare_pack_objects()` will have already
taken care of that.
`write_filtered_pack()` also reads the `pack_kept_objects` field to
determine whether to write the existing kept packs with a leading "^"
character, so update that to read through the `po_args` pointer
instead.
- `cmd_repack()` also no longer has to write the "--honor-pack-keep"
flag explicitly, since this is also handled via its call to
`prepare_pack_objects()`.
Since there is a default value for "pack_kept_objects" that relies on
whether or not we are writing a bitmap (and not writing a MIDX), extract
a default initializer for `struct pack_objects_args` that keeps this
conditional default behavior.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that the pack_geometry API is fully factored and isolated from the
rest of the builtin, declare it within repack.h and move its
implementation to "repack-geometry.c" as a separate component.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
