Some users (myself included) would prefer to have this feature off by
default because it can silently drop commits.
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When writing a commit-graph, a progress meter is shown which indicates
the number of pieces of data to write (one per commit in each chunk).
In 47410aa837 (commit-graph: use chunk-format write API, 2021-02-18),
the number of chunks became tracked by the new chunk-format API. But a
stray local variable was left behind from when write_commit_graph_file()
used to keep track of the same.
Since this was no longer updated after 47410aa837, the progress meter
appeared broken:
$ git commit-graph write --reachable
Expanding reachable commits in commit graph: 837569, done.
Writing out commit graph in 3 passes: 166% (4187845/2512707), done.
Drop the local variable and rely instead on the chunk-format API to tell
us the correct number of chunks.
Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we added a syntax sugar "git push remote --delete <ref>" to
"git push" as a synonym to the canonical "git push remote :<ref>"
syntax at f517f1f2 (builtin-push: add --delete as syntactic sugar
for :foo, 2009-12-30), we weren't careful enough to make sure that
<ref> is not empty.
Blindly rewriting "--delete <ref>" to ":<ref>" means that an empty
string <ref> results in refspec ":", which is the syntax to ask for
"matching" push that does not delete anything.
Worse yet, if there were matching refs that can be fast-forwarded,
they would have been published prematurely, even if the user feels
that they are not ready yet to be pushed out, which would be a real
disaster.
Noticed-by: Tilman Vogel <tilman.vogel@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We describe the more strict date formats accepted by GIT_COMMITTER_DATE,
etc, but the --date option also allows the looser approxidate formats,
as well. Unfortunately we don't have a good or complete reference for
this format, but let's at least mention that it _is_ looser, and give a
few examples.
If we ever write separate, more complete date-format documentation, we
should refer to it from here.
Based-on-a-patch-by: Utku Gultopu <ugultopu@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When an error message informs the user about an incorrect command
invocation, it should refer to "arguments", not "parameters".
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This adds yet another vimdiff/gvimdiff variant and presents conflicts as
a two-way diff between 'LOCAL' and 'REMOTE'. 'MERGED' is not opened
which deviates from the norm so usage text is echoed as a Vim message on
startup that instructs the user with how to proceed and how to abort.
Vimdiff is well-suited to two-way diffs so this is an option for a more
simple, more streamlined conflict resolution. For example: it is
difficult to communicate differences across more than two files using
only syntax highlighting; default vimdiff commands to get and put
changes between buffers do not need the user to manually specify
a source or destination buffer when only using two buffers.
Like other merge tools that directly compare 'LOCAL' with 'REMOTE', this
tool will benefit when paired with the new `mergetool.hideResolved`
setting.
Signed-off-by: Seth House <seth@eseth.com>
Tested-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On Windows we can't delete or overwrite files opened by other processes. Here we
sketch how to handle this situation.
We propose to use a random element in the filename. It's possible to design an
alternate solution based on counters, but that would assign semantics to the
filenames that complicates implementation.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add targets to compile the various *.o files we declared in commonly
used *_OBJS variables. This is useful for debugging purposes, to
e.g. get to the point where we can compile a git.o. See [1] for a
use-case for this target.
https://lore.kernel.org/git/YBCGtd9if0qtuQxx@coredump.intra.peff.net/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a new GIT_OBJS variable, with the objects sufficient to get to a
git.o or common-main.o.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the order of the OBJECTS assignment, this makes a follow-up
change where we split it up into two variables smaller.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Split up the long OBJECTS line into multiple lines using the "+="
assignment we commonly use elsewhere in the Makefile when these lines
get unwieldy.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add TEST_OBJS to the list of other *_OBJS variables we reset. We had
already established this pattern when TEST_OBJS was introduced in
daa99a9172 (Makefile: make sure test helpers are rebuilt when headers
change, 2010-01-26), but it wasn't added to the list in that commit
along with the rest.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The periodic maintenance tasks configured by `git maintenance start`
invoke `git for-each-repo` to run `git maintenance run` on each path
specified by the multi-value global configuration variable
`maintenance.repo`. Because `git for-each-repo` will likely be run
outside of the repositories which require periodic maintenance, it is
mandatory that the repository paths specified by `maintenance.repo` are
absolute.
Unfortunately, however, `git maintenance register` does nothing to
ensure that the paths it assigns to `maintenance.repo` are indeed
absolute, and may in fact -- especially in the case of a bare repository
-- assign a relative path to `maintenance.repo` instead. Fix this
problem by converting all paths to absolute before assigning them to
`maintenance.repo`.
While at it, also fix `git maintenance unregister` to convert paths to
absolute, as well, in order to ensure that it can correctly remove from
`maintenance.repo` a path assigned via `git maintenance register`.
Reported-by: Clement Moyroud <clement.moyroud@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Often it is useful to both:
- have relatively few packfiles in a repository, and
- avoid having so few packfiles in a repository that we repack its
entire contents regularly
This patch implements a '--geometric=<n>' option in 'git repack'. This
allows the caller to specify that they would like each pack to be at
least a factor times as large as the previous largest pack (by object
count).
Concretely, say that a repository has 'n' packfiles, labeled P1, P2,
..., up to Pn. Each packfile has an object count equal to 'objects(Pn)'.
With a geometric factor of 'r', it should be that:
objects(Pi) > r*objects(P(i-1))
for all i in [1, n], where the packs are sorted by
objects(P1) <= objects(P2) <= ... <= objects(Pn).
Since finding a true optimal repacking is NP-hard, we approximate it
along two directions:
1. We assume that there is a cutoff of packs _before starting the
repack_ where everything to the right of that cut-off already forms
a geometric progression (or no cutoff exists and everything must be
repacked).
2. We assume that everything smaller than the cutoff count must be
repacked. This forms our base assumption, but it can also cause
even the "heavy" packs to get repacked, for e.g., if we have 6
packs containing the following number of objects:
1, 1, 1, 2, 4, 32
then we would place the cutoff between '1, 1' and '1, 2, 4, 32',
rolling up the first two packs into a pack with 2 objects. That
breaks our progression and leaves us:
2, 1, 2, 4, 32
^
(where the '^' indicates the position of our split). To restore a
progression, we move the split forward (towards larger packs)
joining each pack into our new pack until a geometric progression
is restored. Here, that looks like:
2, 1, 2, 4, 32 ~> 3, 2, 4, 32 ~> 5, 4, 32 ~> ... ~> 9, 32
^ ^ ^ ^
This has the advantage of not repacking the heavy-side of packs too
often while also only creating one new pack at a time. Another wrinkle
is that we assume that loose, indexed, and reflog'd objects are
insignificant, and lump them into any new pack that we create. This can
lead to non-idempotent results.
Suggested-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a recent patch we added a function 'find_kept_pack_entry()' to look
for an object only among kept packs.
While this function avoids doing any lookup work in non-kept packs, it
is still linear in the number of packs, since we have to traverse the
linked list of packs once per object. Let's cache a reduced version of
that list to save us time.
Note that this cache will last the lifetime of the program. We could
invalidate it on reprepare_packed_git(), but there's not much point in
being rigorous here:
- we might already fail to notice new .keep packs showing up after the
program starts. We only reprepare_packed_git() when we fail to find
an object. But adding a new pack won't cause that to happen.
Somebody repacking could add a new pack and delete an old one, but
most of the time we'd have a descriptor or mmap open to the old
pack anyway, so we might not even notice.
- in pack-objects we already cache the .keep state at startup, since
56dfeb6263 (pack-objects: compute local/ignore_pack_keep early,
2016-07-29). So this is just extending that concept further.
- we don't have to worry about any packed_git being removed; we always
keep the old structs around, even after reprepare_packed_git()
We do defensively invalidate the cache in case the set of kept packs
being asked for changes (e.g., only in-core kept packs were cached, but
suddenly the caller also wants on-disk kept packs, too). In theory we
could build all three caches and switch between them, but it's not
necessary, since this patch (and series) never changes the set of kept
packs that it wants to inspect from the cache.
So that "optimization" is more about being defensive in the face of
future changes than it is about asking for multiple kinds of kept packs
in this patch.
Here are p5303 results (as always, measured against the kernel):
Test HEAD^ HEAD
-----------------------------------------------------------------------------------------------
5303.5: repack (1) 57.34(54.66+10.88) 56.98(54.36+10.98) -0.6%
5303.6: repack with kept (1) 57.38(54.83+10.49) 57.17(54.97+10.26) -0.4%
5303.11: repack (50) 71.70(88.99+4.74) 71.62(88.48+5.08) -0.1%
5303.12: repack with kept (50) 72.58(89.61+4.78) 71.56(88.80+4.59) -1.4%
5303.17: repack (1000) 217.19(491.72+14.25) 217.31(490.82+14.53) +0.1%
5303.18: repack with kept (1000) 246.12(520.07+14.93) 217.08(490.37+15.10) -11.8%
and the --stdin-packs case, which scales a little bit better (although
not by that much even at 1,000 packs):
5303.7: repack with --stdin-packs (1) 0.00(0.00+0.00) 0.00(0.00+0.00) =
5303.13: repack with --stdin-packs (50) 3.43(11.75+0.24) 3.43(11.69+0.30) +0.0%
5303.19: repack with --stdin-packs (1000) 130.50(307.15+7.66) 125.13(301.36+8.04) -4.1%
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that we have find_kept_pack_entry(), we don't have to manually keep
hunting through every pack to find a possible "kept" duplicate of the
object. This should be faster, assuming only a portion of your total
packs are actually kept.
Note that we have to re-order the logic a bit here; we can deal with the
disqualifying situations first (e.g., finding the object in a non-local
pack with --local), then "kept" situation(s), and then just fall back to
other "--local" conditions.
Here are the results from p5303 (measurements again taken on the
kernel):
Test HEAD^ HEAD
-----------------------------------------------------------------------------------------------
5303.5: repack (1) 57.26(54.59+10.84) 57.34(54.66+10.88) +0.1%
5303.6: repack with kept (1) 57.33(54.80+10.51) 57.38(54.83+10.49) +0.1%
5303.11: repack (50) 71.54(88.57+4.84) 71.70(88.99+4.74) +0.2%
5303.12: repack with kept (50) 85.12(102.05+4.94) 72.58(89.61+4.78) -14.7%
5303.17: repack (1000) 216.87(490.79+14.57) 217.19(491.72+14.25) +0.1%
5303.18: repack with kept (1000) 665.63(938.87+15.76) 246.12(520.07+14.93) -63.0%
and the --stdin-packs timings:
5303.7: repack with --stdin-packs (1) 0.01(0.01+0.00) 0.00(0.00+0.00) -100.0%
5303.13: repack with --stdin-packs (50) 3.53(12.07+0.24) 3.43(11.75+0.24) -2.8%
5303.19: repack with --stdin-packs (1000) 195.83(371.82+8.10) 130.50(307.15+7.66) -33.4%
So our repack with an empty .keep pack is roughly as fast as one without
a .keep pack up to 50 packs. But the --stdin-packs case scales a little
better, too.
Notably, it is faster than a repack of the same size and a kept pack. It
looks at fewer objects, of course, but the penalty for looking at many
packs isn't as costly.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add two new tests to measure repack performance. Both tests split the
repository into synthetic "pushes", and then leave the remaining objects
in a big base pack.
The first new test marks an empty pack as "kept" and then passes
--honor-pack-keep to avoid including objects in it. That doesn't change
the resulting pack, but it does let us compare to the normal repack case
to see how much overhead we add to check whether objects are kept or
not.
The other test is of --stdin-packs, which gives us a sense of how that
number scales based on the number of packs we provide as input. In each
of those tests, the empty pack isn't considered, but the residual pack
(objects that were left over and not included in one of the synthetic
push packs) is marked as kept.
(Note that in the single-pack case of the --stdin-packs test, there is
nothing do since there are no non-excluded packs).
Here are some timings on a recent clone of the kernel:
5303.5: repack (1) 57.26(54.59+10.84)
5303.6: repack with kept (1) 57.33(54.80+10.51)
in the 50-pack case, things start to slow down:
5303.11: repack (50) 71.54(88.57+4.84)
5303.12: repack with kept (50) 85.12(102.05+4.94)
and by the time we hit 1,000 packs, things are substantially worse, even
though the resulting pack produced is the same:
5303.17: repack (1000) 216.87(490.79+14.57)
5303.18: repack with kept (1000) 665.63(938.87+15.76)
That's because the code paths around handling .keep files are known to
scale badly; they look in every single pack file to find each object.
Our solution to that was to notice that most repos don't have keep
files, and to make that case a fast path. But as soon as you add a
single .keep, that part of pack-objects slows down again (even if we
have fewer objects total to look at).
Likewise, the scaling is pretty extreme on --stdin-packs (but each
subsequent test is also being asked to do more work):
5303.7: repack with --stdin-packs (1) 0.01(0.01+0.00)
5303.13: repack with --stdin-packs (50) 3.53(12.07+0.24)
5303.19: repack with --stdin-packs (1000) 195.83(371.82+8.10)
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
These are in a helper function, so the usual chain-lint doesn't notice
them. This function is still not perfect, as it has some git invocations
on the left-hand-side of the pipe, but it's primary purpose is timing,
not finding bugs or correctness issues.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In an upcoming commit, 'git repack' will want to create a pack comprised
of all of the objects in some packs (the included packs) excluding any
objects in some other packs (the excluded packs).
This caller could iterate those packs themselves and feed the objects it
finds to 'git pack-objects' directly over stdin, but this approach has a
few downsides:
- It requires every caller that wants to drive 'git pack-objects' in
this way to implement pack iteration themselves. This forces the
caller to think about details like what order objects are fed to
pack-objects, which callers would likely rather not do.
- If the set of objects in included packs is large, it requires
sending a lot of data over a pipe, which is inefficient.
- The caller is forced to keep track of the excluded objects, too, and
make sure that it doesn't send any objects that appear in both
included and excluded packs.
But the biggest downside is the lack of a reachability traversal.
Because the caller passes in a list of objects directly, those objects
don't get a namehash assigned to them, which can have a negative impact
on the delta selection process, causing 'git pack-objects' to fail to
find good deltas even when they exist.
The caller could formulate a reachability traversal themselves, but the
only way to drive 'git pack-objects' in this way is to do a full
traversal, and then remove objects in the excluded packs after the
traversal is complete. This can be detrimental to callers who care
about performance, especially in repositories with many objects.
Introduce 'git pack-objects --stdin-packs' which remedies these four
concerns.
'git pack-objects --stdin-packs' expects a list of pack names on stdin,
where 'pack-xyz.pack' denotes that pack as included, and
'^pack-xyz.pack' denotes it as excluded. The resulting pack includes all
objects that are present in at least one included pack, and aren't
present in any excluded pack.
To address the delta selection problem, 'git pack-objects --stdin-packs'
works as follows. First, it assembles a list of objects that it is going
to pack, as above. Then, a reachability traversal is started, whose tips
are any commits mentioned in included packs. Upon visiting an object, we
find its corresponding object_entry in the to_pack list, and set its
namehash parameter appropriately.
To avoid the traversal visiting more objects than it needs to, the
traversal is halted upon encountering an object which can be found in an
excluded pack (by marking the excluded packs as kept in-core, and
passing --no-kept-objects=in-core to the revision machinery).
This can cause the traversal to halt early, for example if an object in
an included pack is an ancestor of ones in excluded packs. But stopping
early is OK, since filling in the namehash fields of objects in the
to_pack list is only additive (i.e., having it helps the delta selection
process, but leaving it blank doesn't impact the correctness of the
resulting pack).
Even still, it is unlikely that this hurts us much in practice, since
the 'git repack --geometric' caller (which is introduced in a later
commit) marks small packs as included, and large ones as excluded.
During ordinary use, the small packs usually represent pushes after a
large repack, and so are unlikely to be ancestors of objects that
already exist in the repository.
(I found it convenient while developing this patch to have 'git
pack-objects' report the number of objects which were visited and got
their namehash fields filled in during traversal. This is also included
in the below patch via trace2 data lines).
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A future caller will want to be able to perform a reachability traversal
which terminates when visiting an object found in a kept pack. The
closest existing option is '--honor-pack-keep', but this isn't quite
what we want. Instead of halting the traversal midway through, a full
traversal is always performed, and the results are only trimmed
afterwords.
Besides needing to introduce a new flag (since culling results
post-facto can be different than halting the traversal as it's
happening), there is an additional wrinkle handling the distinction
in-core and on-disk kept packs. That is: what kinds of kept pack should
stop the traversal?
Introduce '--no-kept-objects[=<on-disk|in-core>]' to specify which kinds
of kept packs, if any, should stop a traversal. This can be useful for
callers that want to perform a reachability analysis, but want to leave
certain packs alone (for e.g., when doing a geometric repack that has
some "large" packs which are kept in-core that it wants to leave alone).
Note that this option is not guaranteed to produce exactly the set of
objects that aren't in kept packs, since it's possible the traversal
order may end up in a situation where a non-kept ancestor was "cut off"
by a kept object (at which point we would stop traversing). But, we
don't care about absolute correctness here, since this will eventually
be used as a purely additive guide in an upcoming new repack mode.
Explicitly avoid documenting this new flag, since it is only used
internally. In theory we could avoid even adding it rev-list, but being
able to spell this option out on the command-line makes some special
cases easier to test without promising to keep it behaving consistently
forever. Those tricky cases are exercised in t6114.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Future callers will want a function to fill a 'struct pack_entry' for a
given object id but _only_ from its position in any kept pack(s).
In particular, an new 'git repack' mode which ensures the resulting
packs form a geometric progress by object count will mark packs that it
does not want to repack as "kept in-core", and it will want to halt a
reachability traversal as soon as it visits an object in any of the kept
packs. But, it does not want to halt the traversal at non-kept, or
.keep packs.
The obvious alternative is 'find_pack_entry()', but this doesn't quite
suffice since it only returns the first pack it finds, which may or may
not be kept (and the mru cache makes it unpredictable which one you'll
get if there are options).
Short of that, you could walk over all packs looking for the object in
each one, but it scales with the number of packs, which may be
prohibitive.
Introduce 'find_kept_pack_entry()', a function which is like
'find_pack_entry()', but only fills in objects in the kept packs.
Handle packs which have .keep files, as well as in-core kept packs
separately, since certain callers will want to distinguish one from the
other. (Though on-disk and in-core kept packs share the adjective
"kept", it is best to think of the two sets as independent.)
There is a gotcha when looking up objects that are duplicated in kept
and non-kept packs, particularly when the MIDX stores the non-kept
version and the caller asked for kept objects only. This could be
resolved by teaching the MIDX to resolve duplicates by always favoring
the kept pack (if one exists), but this breaks an assumption in existing
MIDXs, and so it would require a format change.
The benefit to changing the MIDX in this way is marginal, so we instead
have a more thorough check here which is explained with a comment.
Callers will be added in subsequent patches.
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Test framework clean-up.
* ab/test-lib:
test-lib-functions: assert correct parameter count
test-lib-functions: remove bug-inducing "diagnostics" helper param
test libs: rename "diff-lib" to "lib-diff"
t/.gitattributes: sort lines
test-lib-functions: move function to lib-bitmap.sh
test libs: rename gitweb-lib.sh to lib-gitweb.sh
test libs: rename bundle helper to "lib-bundle.sh"
test-lib-functions: remove generate_zero_bytes() wrapper
test-lib-functions: move test_set_index_version() to its user
test lib: change "error" to "BUG" as appropriate
test-lib: remove check_var_migration
A small memleak in "diff -I<regexp>" has been corrected.
* ab/diff-deferred-free:
diff: plug memory leak from regcomp() on {log,diff} -I
diff: add an API for deferred freeing
When a pager spawned by us exited, the trace log did not record its
exit status correctly, which has been corrected.
* ab/pager-exit-log:
pager: properly log pager exit code when signalled
run-command: add braces for "if" block in wait_or_whine()
pager: test for exit code with and without SIGPIPE
pager: refactor wait_for_pager() function
Update formatting and grammar of the hash transition plan
documentation, plus some updates.
* ta/hash-function-transition-doc:
doc: use https links
doc hash-function-transition: move rationale upwards
doc hash-function-transition: fix incomplete sentence
doc hash-function-transition: use upper case consistently
doc hash-function-transition: use SHA-1 and SHA-256 consistently
doc hash-function-transition: fix asciidoc output
Signed commits and tags now allow verification of objects, whose
two object names (one in SHA-1, the other in SHA-256) are both
signed.
* bc/signed-objects-with-both-hashes:
gpg-interface: remove other signature headers before verifying
ref-filter: hoist signature parsing
commit: allow parsing arbitrary buffers with headers
gpg-interface: improve interface for parsing tags
commit: ignore additional signatures when parsing signed commits
ref-filter: switch some uses of unsigned long to size_t
Documentation, code and test clean-up around "git stash".
* dl/stash-cleanup:
stash: declare ref_stash as an array
t3905: use test_cmp() to check file contents
t3905: replace test -s with test_file_not_empty
t3905: remove nested git in command substitution
t3905: move all commands into test cases
t3905: remove spaces after redirect operators
git-stash.txt: be explicit about subcommand options
write_commit_graph initialises topo_levels using init_topo_level_slab(),
next it calls compute_topological_levels() which can cause the slab to
grow, we therefore need to clear the slab again using
clear_topo_level_slab() when we're done.
First introduced in 72a2bfca (commit-graph: add a slab to store
topological levels, 2021-01-16).
LeakSanitizer output:
==1026==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 8 byte(s) in 1 object(s) allocated from:
#0 0x498ae9 in realloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0xafbed8 in xrealloc /src/git/wrapper.c:126:8
#2 0x7966d1 in topo_level_slab_at_peek /src/git/commit-graph.c:71:1
#3 0x7965e0 in topo_level_slab_at /src/git/commit-graph.c:71:1
#4 0x78fbf5 in compute_topological_levels /src/git/commit-graph.c:1472:12
#5 0x78c5c3 in write_commit_graph /src/git/commit-graph.c:2456:2
#6 0x535c5f in graph_write /src/git/builtin/commit-graph.c:299:6
#7 0x5350ca in cmd_commit_graph /src/git/builtin/commit-graph.c:337:11
#8 0x4cddb1 in run_builtin /src/git/git.c:453:11
#9 0x4cabe2 in handle_builtin /src/git/git.c:704:3
#10 0x4cd084 in run_argv /src/git/git.c:771:4
#11 0x4ca424 in cmd_main /src/git/git.c:902:19
#12 0x707fb6 in main /src/git/common-main.c:52:11
#13 0x7fee4249383f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
Indirect leak of 524256 byte(s) in 1 object(s) allocated from:
#0 0x498942 in calloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
#1 0xafc088 in xcalloc /src/git/wrapper.c:140:8
#2 0x796870 in topo_level_slab_at_peek /src/git/commit-graph.c:71:1
#3 0x7965e0 in topo_level_slab_at /src/git/commit-graph.c:71:1
#4 0x78fbf5 in compute_topological_levels /src/git/commit-graph.c:1472:12
#5 0x78c5c3 in write_commit_graph /src/git/commit-graph.c:2456:2
#6 0x535c5f in graph_write /src/git/builtin/commit-graph.c:299:6
#7 0x5350ca in cmd_commit_graph /src/git/builtin/commit-graph.c:337:11
#8 0x4cddb1 in run_builtin /src/git/git.c:453:11
#9 0x4cabe2 in handle_builtin /src/git/git.c:704:3
#10 0x4cd084 in run_argv /src/git/git.c:771:4
#11 0x4ca424 in cmd_main /src/git/git.c:902:19
#12 0x707fb6 in main /src/git/common-main.c:52:11
#13 0x7fee4249383f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
SUMMARY: AddressSanitizer: 524264 byte(s) leaked in 2 allocation(s).
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`git difftool` only allow us to select file to view in turn.
If there is a commit with many files and we exit in the middle,
we will have to traverse list again to get the file diff which
we want to see. Therefore,teach the command an option
`--skip-to=<path>` to allow the user to say that diffs for earlier
paths are not interesting (because they were already seen in an
earlier session) and start this session with the named path.
Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The remove_redundant_with_gen() algorithm performs a depth-first-search
to find commits in the 'array' list, starting at the parents of each
commit in 'array'. The result is that commits in 'array' are marked
STALE when they are reachable from another commit in 'array'.
This depth-first-search is fast when commits lie on or near the
first-parent history of the higher commits. The search terminates early
if all but one commit becomes marked STALE.
However, it is possible that there are two independent commits with high
generation number. In that case, the depth-first-search might languish
by searching in lower generations due to the fixed min_generation used
throughout the method.
With the expectation that commits with lower generation are expected to
become STALE more often, we can optimize further by increasing that
min_generation boundary upon discovery of the commit with minimum
generation.
We must first sort the commits in 'array' by generation. We cannot sort
'array' itself since it must preserve relative order among the returned
results (see revision.c:mark_redundant_parents() for an example).
This simplifies the initialization of min_generation, but it also allows
us to increase the new min_generation when we find the commit with
smallest generation remaining.
This requires more than two commits in order to test, so I used the
Linux kernel repository with a few commits that are slightly off of the
first-parent history. I timed the following command:
git merge-base --independent 2ecedd756908 d2360a398f0b \
1253935ad801 160bab43419e 0e2209629fec 1d0e16ac1a9e
The first two commits have similar generation and are near the v5.10
tag. Commit 160bab43419e is off of the first-parent history behind v5.5,
while the others are scattered somewhere reachable from v5.9. This is
designed to demonstrate the optimization, as that commit within v5.5
would normally cause a lot of extra commit walking.
Since remove_redundant_with_alg() is called only when at least one of
the input commits has a finite generation number, this algorithm is
tested with a commit-graph generated starting at a number of different
tags, the earliest being v5.5.
commit-graph at v5.5:
| Method | Time |
|-----------------------+-------|
| *_no_gen() | 864ms |
| *_with_gen() (before) | 858ms |
| *_with_gen() (after) | 810ms |
commit-graph at v5.7:
| Method | Time |
|-----------------------+-------|
| *_no_gen() | 625ms |
| *_with_gen() (before) | 572ms |
| *_with_gen() (after) | 517ms |
commit-graph at v5.9:
| Method | Time |
|-----------------------+-------|
| *_no_gen() | 268ms |
| *_with_gen() (before) | 224ms |
| *_with_gen() (after) | 202ms |
commit-graph at v5.10:
| Method | Time |
|-----------------------+-------|
| *_no_gen() | 72ms |
| *_with_gen() (before) | 37ms |
| *_with_gen() (after) | 9ms |
Note that these are only modest improvements for the case where the two
independent commits are not in the commit-graph (not until v5.10). All
algorithms get faster as more commits are indexed, which is not a
surprise. However, the cost of walking extra commits is more and more
prevalent in relative terms as more commits are indexed. Finally, the
last case allows us to jump to the minimum generation between the last
two commits (that are actually independent) so we greatly reduce the
cost in that case.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reachability algorithms in commit-reach.c frequently benefit from using
the first-parent history as a heuristic for satisfying reachability
queries. The most obvious example was implemented in 4fbcca4e
(commit-reach: make can_all_from_reach... linear, 2018-07-20).
Update the walk in remove_redundant() to use this same heuristic. Here,
we are walking starting at the parents of the input commits. Sort those
parents and walk from the highest generation to lower. Each time, use
the heuristic of searching the first parent history before continuing to
expand the walk.
The order in which we explore the commits matters, so update
compare_commits_by_gen to break generation number ties with commit date.
This has no effect when the commits are in a commit-graph file with
corrected commit dates computed, but it will assist when the commits are
in the region "above" the commit-graph with "infinite" generation
number. Note that we cannot shift to use
compare_commits_by_gen_then_commit_date as the method prototype is
different. We use compare_commits_by_gen for QSORT() as opposed to as a
priority function.
The important piece is to ensure we short-circuit the walk when we find
that there is a single non-redundant commit. This happens frequently
when looking for merge-bases or comparing several tags with 'git
merge-base --independent'. Use a new count 'count_still_independent' and
if that hits 1 we can stop walking.
To update 'count_still_independent' properly, we add use of the RESULT
flag on the input commits. Then we can detect when we reach one of these
commits and decrease the count. We need to remove the RESULT flag at
that moment because we might re-visit that commit when popping the
stack.
We use the STALE flag to mark parents that have been added to the new
walk_start list, but we need to clear that flag before we start walking
so those flags don't halt our depth-first-search walk.
On my copy of the Linux kernel repository, the performance of 'git
merge-base --independent <all-tags>' goes from 1.1 seconds to 0.11
seconds.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move this earlier in the file so it can be used by more methods.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The current implementation of remove_redundant() uses several calls to
paint_down_to_common() to determine that commits are independent of each
other. This leads to quadratic behavior when many inputs are passed to
commands such as 'git merge-base'.
For example, in the Linux kernel repository, I tested the performance
by passing all tags:
git merge-base --independent $(git for-each-ref refs/tags --format="$(refname)")
(Note: I had to delete the tags v2.6.11-tree and v2.6.11 as they do
not point to commits.)
Here is the performance improvement introduced by this change:
Before: 16.4s
After: 1.1s
This performance improvement requires the commit-graph file to be
present. We keep the old algorithm around as remove_redundant_no_gen()
and use it when generation_numbers_enabled() is false. This is similar
to other algorithms within commit-reach.c. The new algorithm is
implemented in remove_redundant_with_gen().
The basic approach is to do one commit walk instead of many. First, scan
all commits in the list and mark their _parents_ with the STALE flag.
This flag will indicate commits that are reachable from one of the
inputs, except not including themselves. Then, walk commits until
covering all commits up to the minimum generation number pushing the
STALE flag throughout.
At the end, we need to clear the STALE bit from all of the commits
we walked. We move the non-stale commits in 'array' to the beginning of
the list, and this might overwrite stale commits. However, we store an
array of commits that started the walk, and use clear_commit_marks() on
each of those starting commits. That method will walk the reachable
commits with the STALE bit and clear them all. This makes the algorithm
safe for re-entry or for other uses of those commits after this walk.
This logic is covered by tests in t6600-test-reach.sh, so the behavior
does not change. This is tested both in the case with a commit-graph and
without.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Knowing about the core.bigFileThreshold configuration variable is
helpful when examining pack file size differences between repositories.
Add a reference to it to the manpages a user is likely to read in this
situation.
Capitalize CONFIGURATION for consistency with other pages having such a
section.
Signed-off-by: Christian Walther <cwalther@gmx.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach index-pack to print dangling .gitmodules links after its "keep" or
"pack" line instead of declaring an error, and teach fetch-pack to check
such lines printed.
This allows the tree side of the .gitmodules link to be in one packfile
and the blob side to be in another without failing the fsck check,
because it is now fetch-pack which checks such objects after all
packfiles have been downloaded and indexed (and not index-pack on an
individual packfile, as it is before this commit).
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Unify the index-pack arguments used when processing the inline pack and
when downloading packfiles referenced by URIs. This is done by teaching
get_pack() to also store the index-pack arguments whenever at least one
packfile URI is given, and then when processing the packfile URI(s),
using the stored arguments.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is the next step in teaching fetch-pack to pass its index-pack
arguments when processing packfiles referenced by URIs.
The "--keep" in fetch-pack.c will be replaced with a full message in a
subsequent commit.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently, when fetching, packfiles referenced by URIs are run through
index-pack without any arguments other than --stdin and --keep, no
matter what arguments are used for the packfile that is inline in the
fetch response. As a preparation for ensuring that all packs (whether
inline or not) use the same index-pack arguments, teach the http
subsystem to allow custom index-pack arguments.
http-fetch has been updated to use the new API. For now, it passes
--keep alone instead of --keep with a process ID, but this is only
temporary because http-fetch itself will be taught to accept index-pack
parameters (instead of using a hardcoded constant) in a subsequent
commit.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use git-stripspace to remove comment lines from the commit message. Also
use it to clean up whitespace instead of rolling our own logic.
* py/commit-comments:
git-gui: remove lines starting with the comment character
f4ed0af6 (Merge branch 'nd/columns', 2012-05-03) brought in three
cut-and-pasted copies of malformatted descriptions. Let's fix them
all the same way by marking the configuration variable names up as
monospace just like the command line option `--column` is typeset.
While we are at it, correct a missing space after the full stop that
ends the sentence.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The chunk-based file format is now an API in the code, but we should
also take time to document it as a file format. Specifically, it matches
the CHUNK LOOKUP sections of the commit-graph and multi-pack-index
files, but there are some commonalities that should be grouped in this
document.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before refactoring into the chunk-format API, the commit-graph parsing
logic included checks for duplicate chunks. It is unlikely that we would
desire a chunk-based file format that allows duplicate chunk IDs in the
table of contents, so add duplicate checks into
read_table_of_contents().
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When calculating the sizes of certain chunks, we should use 64-bit
multiplication always. This allows us to properly predict the chunk
sizes without risk of overflow.
Other possible overflows were discovered by evaluating each
multiplication in midx.c and ensuring that at least one side of the
operator was of type size_t or off_t.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of parsing the table of contents directly, use the chunk-format
API methods read_table_of_contents() and pair_chunk(). In particular, we
can use the return value of pair_chunk() to generate an error when a
required chunk is missing.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of parsing the table of contents directly, use the chunk-format
API methods read_table_of_contents() and pair_chunk(). While the current
implementation loses the duplicate-chunk detection, that will be added
in a future change.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add the capability to read the table of contents, then pair the chunks
with necessary logic using read_chunk_fn pointers. Callers will be added
in future changes, but the typical outline will be:
1. initialize a 'struct chunkfile' with init_chunkfile(NULL).
2. call read_table_of_contents().
3. for each chunk to parse,
a. call pair_chunk() to assign a pointer with the chunk position, or
b. call read_chunk() to run a callback on the chunk start and size.
4. call free_chunkfile() to clear the 'struct chunkfile' data.
We are re-using the anonymous 'struct chunkfile' data, as it is internal
to the chunk-format API. This gives it essentially two modes: write and
read. If the same struct instance was used for both reads and writes,
then there would be failures.
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The chunk-format API allows writing the table of contents and all chunks
using the anonymous 'struct chunkfile' type. We only need to convert our
local chunk logic to this API for the multi-pack-index writes to share
that logic with the commit-graph file writes.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most expensive operations in write_midx_internal() use the context
struct's progress member, and these indicate the process of the
expensive operations within the chunk writing methods. However, there is
a competing progress struct that counts the progress over all chunks.
This is not very helpful compared to the others, so drop it.
This also reduces our barriers to combining the chunk writing code with
chunk-format.c.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Alex Henrie
Taylor Blau
Jordi Mas
Junio C Hamano
Jeff King
Johannes Sixt
Seth House
Han-Wen Nienhuys
Ævar Arnfjörð Bjarmason
Eric Sunshine
Andrzej Hunt
ZheNing Hu
Derrick Stolee
Christian Walther
Jonathan Tan
Pratyush Yadav