In a previous patch, pack-objects learned how to generate a cruft pack
so long as no objects are dropped.
This patch teaches pack-objects to handle the case where a non-never
`--cruft-expiration` value is passed. This case is slightly more
complicated than before, because we want pack-objects to save
unreachable objects which would have been pruned when there is another
recent (i.e., non-prunable) unreachable object which reaches the other.
We'll call these objects "unreachable but reachable-from-recent".
Here is how pack-objects handles `--cruft-expiration`:
- Instead of adding all objects outside of the kept pack(s) into the
packing list, only handle the ones whose mtime is within the grace
period.
- Construct a reachability traversal whose tips are the
unreachable-but-recent objects.
- Then, walk along that traversal, stopping if we reach an object in
the kept pack. At each step along the traversal, we add the object
we are visiting to the packing list.
In the majority of these cases, any object we visit in this traversal
will already be in our packing list. But we will sometimes encounter
reachable-from-recent cruft objects, which we want to retain even if
they aged out of the grace period.
The most subtle point of this process is that we actually don't need to
bother to update the rescued object's mtime. Even though we will write
an .mtimes file with a value that is older than the expiration window,
it will continue to survive cruft repacks so long as any objects which
reach it haven't aged out.
That is, a future repack will also exclude that object from the initial
packing list, only to discover it later on when doing the reachability
traversal.
Finally, stopping early once an object is found in a kept pack is safe
to do because the kept packs ordinarily represent which packs will
survive after repacking. Assuming that it _isn't_ safe to halt a
traversal early would mean that there is some ancestor object which is
missing, which implies repository corruption (i.e., the complete set of
reachable objects isn't present).
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When generating a cruft pack, the caller within pack-objects will want
to know the precise timestamps of cruft objects (i.e., their
corresponding values in the .mtimes table) rather than the mtime of the
cruft pack itself.
Teach add_recent_packed() to lookup each object's precise mtime from the
.mtimes file if one exists (indicated by the is_cruft bit on the
packed_git structure).
A couple of small things worth noting here:
- load_pack_mtimes() needs to be called before asking for
nth_packed_mtime(), and that call is done lazily here. That function
exits early if the .mtimes file has already been opened and parsed,
so only the first call is slow.
- Checking the is_cruft bit can be done without any extra work on the
caller's behalf, since it is set up for us automatically as a
side-effect of calling add_packed_git() (just like the 'pack_keep'
and 'pack_promisor' bits).
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function behaves very similarly to what we will need in
pack-objects in order to implement cruft packs with expiration. But it
is lacking a couple of things. Namely, it needs:
- a mechanism to communicate the timestamps of individual recent
objects to some external caller
- and, in the case of packed objects, our future caller will also want
to know the originating pack, as well as the offset within that pack
at which the object can be found
- finally, it needs a way to skip over packs which are marked as kept
in-core.
To address the first two, add a callback interface in this patch which
reports the time of each recent object, as well as a (packed_git,
off_t) pair for packed objects.
Likewise, add a new option to the packed object iterators to skip over
packs which are marked as kept in core. This option will become
implicitly tested in a future patch.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach `pack-objects` how to generate a cruft pack when no objects are
dropped (i.e., `--cruft-expiration=never`). Later patches will teach
`pack-objects` how to generate a cruft pack that prunes objects.
When generating a cruft pack which does not prune objects, we want to
collect all unreachable objects into a single pack (noting and updating
their mtimes as we accumulate them). Ordinary use will pass the result
of a `git repack -A` as a kept pack, so when this patch says "kept
pack", readers should think "reachable objects".
Generating a non-expiring cruft packs works as follows:
- Callers provide a list of every pack they know about, and indicate
which packs are about to be removed.
- All packs which are going to be removed (we'll call these the
redundant ones) are marked as kept in-core.
Any packs the caller did not mention (but are known to the
`pack-objects` process) are also marked as kept in-core. Packs not
mentioned by the caller are assumed to be unknown to them, i.e.,
they entered the repository after the caller decided which packs
should be kept and which should be discarded.
Since we do not want to include objects in these "unknown" packs
(because we don't know which of their objects are or aren't
reachable), these are also marked as kept in-core.
- Then, we enumerate all objects in the repository, and add them to
our packing list if they do not appear in an in-core kept pack.
This results in a new cruft pack which contains all known objects that
aren't included in the kept packs. When the kept pack is the result of
`git repack -A`, the resulting pack contains all unreachable objects.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A new caller in the next commit will want to immediately modify the
object_entry structure created by create_object_entry(). Instead of
forcing that caller to wastefully look-up the entry we just created,
return it from create_object_entry() instead.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the next patch, we will implement and test support for writing a
cruft pack via a special mode of `git pack-objects`. To make sure that
objects are written with the correct timestamps, and a new test-tool
that can dump the object names and corresponding timestamps from a given
`.mtimes` file.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that the `.mtimes` format is defined, supplement the pack-write API
to be able to conditionally write an `.mtimes` file along with a pack by
setting an additional flag and passing an oidmap that contains the
timestamps corresponding to each object in the pack.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are three definitions of an identical function which converts
`the_hash_algo` into either 1 (for SHA-1) or 2 (for SHA-256). There is a
copy of this function for writing both the commit-graph and
multi-pack-index file, and another inline definition used to write the
.rev header.
Consolidate these into a single definition in chunk-format.h. It's not
clear that this is the best header to define this function in, but it
should do for now.
(Worth noting, the .rev caller expects a 4-byte unsigned, but the other
two callers work with a single unsigned byte. The consolidated version
uses the latter type, and lets the compiler widen it when required).
Another caller will be added in a subsequent patch.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This structure will be used to communicate the per-object mtimes when
writing a cruft pack. Here, we need the full packing_data structure
because the mtime information is stored in an array there, not on the
individual object_entry's themselves (to avoid paying the overhead in
structure width for operations which do not generate a cruft pack).
We haven't passed this information down before because one of the two
callers (in bulk-checkin.c) does not have a packing_data structure at
all. In that case (where no cruft pack will be generated), NULL is
passed instead.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To store the individual mtimes of objects in a cruft pack, introduce a
new `.mtimes` format that can optionally accompany a single pack in the
repository.
The format is defined in Documentation/technical/pack-format.txt, and
stores a 4-byte network order timestamp for each object in name (index)
order.
This patch prepares for cruft packs by defining the `.mtimes` format,
and introducing a basic API that callers can use to read out individual
mtimes.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create a technical document to explain cruft packs. It contains a brief
overview of the problem, some background, details on the implementation,
and a couple of alternative approaches not considered here.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A couple of work around for CI breaking warnings from gcc 12.
* cb/buggy-gcc-12-workaround:
config.mak.dev: alternative workaround to gcc 12 warning in http.c
config.mak.dev: workaround gcc 12 bug affecting "pedantic" CI job
This provides a "no code change needed" option to the "fix" currently
queued as part of ab/http-gcc-12-workaround and therefore should be
reverted once that gets merged.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Originally noticed by Peff[1], but yet to be corrected[2] and planned to
be released with Fedora 36 (scheduled for Apr 19).
dir.c: In function ‘git_url_basename’:
dir.c:3085:13: error: ‘memchr’ specified bound [9223372036854775808, 0] exceeds maximum object size 9223372036854775807 [-Werror=stringop-overread]
3085 | if (memchr(start, '/', end - start) == NULL
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fedora is used as part of the CI, and therefore that release will trigger
failures, unless the version of the image used is locked to an older
release, as an alternative.
Restricting the flag to the affected source file, as well as implementing
an independent facility to track these workarounds was specifically punted
to minimize the risk of introducing problems so close to a release.
This change should be reverted once the underlying gcc bug is solved and
which should be visible by NOT triggering a warning, otherwise.
[1] https://lore.kernel.org/git/YZQhLh2BU5Hquhpo@coredump.intra.peff.net/
[2] https://bugzilla.redhat.com/show_bug.cgi?id=2075786
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Revert the "deletion of a ref should not trigger transaction events
for loose and packed ref backends separately" that regresses the
behaviour when a ref is not modified since it was packed.
* jc/revert-ref-transaction-hook-changes:
RelNotes: revert the description on the reverted topics
Revert "fetch: increase test coverage of fetches"
Revert "Merge branch 'ps/avoid-unnecessary-hook-invocation-with-packed-refs'"
* update the following words translations: commit, untracked, stage,
cache, stash, work..., index, reset, label, check..., tags, graft,
alternate object, amend, ancestor, cherry-pick, bisect, blame, chain,
cache, bug, chunk, branch, bundle, clean, clone, commit-graph, commit
object, commit-ish, committer, cover letter, conflict, dangling,
detach, dir, dumb, fast-forward, file system, fixup, fork, fetch, Git
archive, gitdir, graft, replace ref
* correct some mispellings
* git-po-helper update
* remove some obsolete lines
* unfuzzy entries
* random translation updates
* update contact in pt_PT.po
* add the following words to the translation table: override, recurse,
print, offset, unbundle, mirror repository, multi-pack, bad,
whitespace, batch
* remove the following words of the translation table: core Git
* change the following words on the translation table: dry-run, apply,
patch, replay, blame, chain, gitdir, file system, fork, unset, handle
* some translation to the first person
* update copyright text
* word 'utilização:' to 'uso:'
* word 'pai' to 'parente'
Signed-off-by: Daniel Santos <dacs.git@brilhante.top>
We do not have to guess how common the mistake the change targets is
when describing it. Such an argument may be good while proposing a
change, but does not quite belong in the record of what has already
happened, i.e. a release note.
Helped-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit 2a0cafd464,
as it expects a working "a ref deletion must produce a single
transaction, not one for loose and another for packed" topic,
which we do not have.
With the addition of the safe.directory in 8959555ce
(setup_git_directory(): add an owner check for the top-level directory,
2022-03-02) released in v2.35.2, we are receiving feedback from a
variety of users about the feature.
Some users have a very large list of shared repositories and find it
cumbersome to add this config for every one of them.
In a more difficult case, certain workflows involve running Git commands
within containers. The container boundary prevents any global or system
config from communicating `safe.directory` values from the host into the
container. Further, the container almost always runs as a different user
than the owner of the directory in the host.
To simplify the reactions necessary for these users, extend the
definition of the safe.directory config value to include a possible '*'
value. This value implies that all directories are safe, providing a
single setting to opt-out of this protection.
Note that an empty assignment of safe.directory clears all previous
values, and this is already the case with the "if (!value || !*value)"
condition.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It seems that nothing is ever checking to make sure the safe directories
in the configs actually have the key safe.directory, so some unrelated
config that has a value with a certain directory would also make it a
safe directory.
Signed-off-by: Matheus Valadares <me@m28.io>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is difficult to change the ownership on a directory in our test
suite, so insert a new GIT_TEST_ASSUME_DIFFERENT_OWNER environment
variable to trick Git into thinking we are in a differently-owned
directory. This allows us to test that the config is parsed correctly.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* 'master' of github.com:git/git: (25 commits)
Git 2.36-rc2
i18n: fix some badly formatted i18n strings
Git 2.36-rc1
t9902: split test to run on appropriate systems
ls-tree doc: document interaction with submodules
Documentation: add --batch-command to cat-file synopsis
git-ls-tree.txt: fix the name of "%(objectsize:padded)"
submodule-helper: fix usage string
doc: replace "--" with {litdd} in credential-cache/fsmonitor
contrib/scalar: fix 'all' target in Makefile
Documentation/Makefile: fix "make info" regression in dad9cd7d51
configure.ac: fix HAVE_SYNC_FILE_RANGE definition
git-compat-util: really support openssl as a source of entropy
ls-tree: `-l` should not imply recursive listing
Git 2.35.2
Git 2.34.2
Git 2.33.2
Git 2.32.1
Git 2.31.2
Git 2.30.3
...
