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With the codebase firmly C99 compatible and most compilers supporting
newer versions by default, it could help bring visibility to problems.
Reverse the DEVOPTS=pedantic flag to provide a fallback for people stuck
with gcc < 5 or some other compiler that either doesn't support this flag
or has issues with it, and while at it also enable -Wpedantic which used
to be controversial[1] when Apple compilers and clang had widely divergent
version numbers.
Ideally any compiler found to have issues with these flags will be added
to an exception, and indeed, one was added to safely process windows
headers that would use non standard print identifiers, but it is expected
that more will be needed, so it could be considered a weather balloon.
[1] https://lore.kernel.org/git/20181127100557.53891-1-carenas@gmail.com/
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In preparation to building with pedantic mode enabled, change a couple
of places where the current mingw gcc compiler provided with the SDK
reports issues.
A full fix for the incompatible use of (void *) to store function
pointers has been punted, with the minimal change to instead use a
generic function pointer (FARPROC), and therefore the (hopefully)
temporary need to disable incompatible pointer warnings.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Remove the USE_PARENS_AROUND_GETTEXT_N compile-time option which was
meant to catch an inadvertent mistake which is too obscure to
maintain this facility.
The backstory of how USE_PARENS_AROUND_GETTEXT_N came about is: When I
added the N_() macro in 65784830366 (i18n: add no-op _() and N_()
wrappers, 2011-02-22) it was defined as:
#define N_(msgid) (msgid)
This is non-standard C, as was noticed and fixed in 642f85faab2 (i18n:
avoid parenthesized string as array initializer, 2011-04-07).
I.e. this needed to be defined as:
#define N_(msgid) msgid
Then in e62cd35a3e8 (i18n: log: mark parseopt strings for translation,
2012-08-20) when "builtin_log_usage" was marked for translation the
string concatenation for passing to usage() added in 1c370ea4e51
(Show usage string for 'git log -h', 'git show -h' and 'git diff -h',
2009-08-06) was faithfully preserved:
- "git log [<options>] [<since>..<until>] [[--] <path>...]\n"
- " or: git show [options] <object>...",
+ N_("git log [<options>] [<since>..<until>] [[--] <path>...]\n")
+ N_(" or: git show [options] <object>..."),
This was then fixed to be the expected array of usage strings in
e66dc0cc4b1 (log.c: fix translation markings, 2015-01-06) rather than
a string with multiple "\n"-delimited usage strings, and finally in
290c8e7a3fe (gettext.h: add parentheses around N_ expansion if
supported, 2015-01-11) USE_PARENS_AROUND_GETTEXT_N was added to ensure
this mistake didn't happen again.
I think that even if this was a N_()-specific issue this
USE_PARENS_AROUND_GETTEXT_N facility wouldn't be worth it, the issue
would be too rare to worry about.
But I also think that 290c8e7a3fe which introduced
USE_PARENS_AROUND_GETTEXT_N misattributed the problem. The issue
wasn't with the N_() macro added in e62cd35a3e8, but that before the
N_() macro existed in the codebase the initial migration to
parse_options() in 1c370ea4e51 continued passsing in a "\n"-delimited
string, when the new API it was migrating to supported and expected
the passing of an array.
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When executing git-update-ref(1) with the `--stdin` flag, then the user
can queue updates and, since e48cf33b61 (update-ref: implement
interactive transaction handling, 2020-04-02), interactively drive the
transaction's state via a set of transactional verbs. This interactivity
is somewhat broken though: while the caller can use these verbs to drive
the transaction's state, the status messages which confirm that a verb
has been processed is not flushed. The caller may thus be left hanging
waiting for the acknowledgement.
Fix the bug by flushing stdout after writing the status update. Add a
test which catches this bug.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In make_remote(), we store the return value of hashmap_put() and check
it using assert(), but don't otherwise use it. If Git is compiled with
NDEBUG, then the assert() becomes a noop, and nobody looks at the
variable at all. This causes some compilers to produce warnings.
Let's switch it instead to a BUG(). This accomplishes the same thing,
but is always compiled in (and we don't have to worry about the cost;
the check is cheap, and this is not a hot code path).
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Remove the trailing dot from the warning we emit about gc.log. It's
common for various terminal UX's to allow the user to select "words",
and by including the trailing dot a user wanting to select the path to
gc.log will need to manually remove the trailing dot.
Such a user would also probably need to adjust the path if it e.g. had
spaces in it, but this should address this very common case.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Suggested-by: Jan Judas <snugar.i@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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These new performance tests demonstrate effectively the same behavior as
p5310, but use a multi-pack bitmap instead of a single-pack one.
Notably, p5326 does not create a MIDX bitmap with multiple packs. This
is so we can measure a direct comparison between it and p5310. Any
difference between the two is measuring just the overhead of using MIDX
bitmaps.
Here are the results of p5310 and p5326 together, measured at the same
time and on the same machine (using a Xenon W-2255 CPU):
Test HEAD
------------------------------------------------------------------------
5310.2: repack to disk 96.78(93.39+11.33)
5310.3: simulated clone 9.98(9.79+0.19)
5310.4: simulated fetch 1.75(4.26+0.19)
5310.5: pack to file (bitmap) 28.20(27.87+8.70)
5310.6: rev-list (commits) 0.41(0.36+0.05)
5310.7: rev-list (objects) 1.61(1.54+0.07)
5310.8: rev-list count with blob:none 0.25(0.21+0.04)
5310.9: rev-list count with blob:limit=1k 2.65(2.54+0.10)
5310.10: rev-list count with tree:0 0.23(0.19+0.04)
5310.11: simulated partial clone 4.34(4.21+0.12)
5310.13: clone (partial bitmap) 11.05(12.21+0.48)
5310.14: pack to file (partial bitmap) 31.25(34.22+3.70)
5310.15: rev-list with tree filter (partial bitmap) 0.26(0.22+0.04)
versus the same tests (this time using a multi-pack index):
Test HEAD
------------------------------------------------------------------------
5326.2: setup multi-pack index 78.99(75.29+11.58)
5326.3: simulated clone 11.78(11.56+0.22)
5326.4: simulated fetch 1.70(4.49+0.13)
5326.5: pack to file (bitmap) 28.02(27.72+8.76)
5326.6: rev-list (commits) 0.42(0.36+0.06)
5326.7: rev-list (objects) 1.65(1.58+0.06)
5326.8: rev-list count with blob:none 0.26(0.21+0.05)
5326.9: rev-list count with blob:limit=1k 2.97(2.86+0.10)
5326.10: rev-list count with tree:0 0.25(0.20+0.04)
5326.11: simulated partial clone 5.65(5.49+0.16)
5326.13: clone (partial bitmap) 12.22(13.43+0.38)
5326.14: pack to file (partial bitmap) 30.05(31.57+7.25)
5326.15: rev-list with tree filter (partial bitmap) 0.24(0.20+0.04)
There is slight overhead in "simulated clone", "simulated partial
clone", and "clone (partial bitmap)". Unsurprisingly, that overhead is
due to using the MIDX's reverse index to map between bit positions and
MIDX positions.
This can be reproduced by running "git repack -adb" along with "git
multi-pack-index write --bitmap" in a large-ish repository. Then run:
$ perf record -o pack.perf git -c core.multiPackIndex=false \
pack-objects --all --stdout >/dev/null </dev/null
$ perf record -o midx.perf git -c core.multiPackIndex=true \
pack-objects --all --stdout >/dev/null </dev/null
and compare the two with "perf diff -c delta -o 1 pack.perf midx.perf".
The most notable results are below (the next largest positive delta is
+0.14%):
# Event 'cycles'
#
# Baseline Delta Shared Object Symbol
# ........ ....... .................. ..........................
#
+5.86% git [.] nth_midxed_offset
+5.24% git [.] nth_midxed_pack_int_id
3.45% +0.97% git [.] offset_to_pack_pos
3.30% +0.57% git [.] pack_pos_to_offset
+0.30% git [.] pack_pos_to_midx
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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A new p5326 introduced by the next patch will want these same tests,
interjecting its own setup in between. Move them out so that both perf
tests can reuse them.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Introduce a new 'GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP' environment
variable to also write a multi-pack bitmap when
'GIT_TEST_MULTI_PACK_INDEX' is set.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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A number of these tests are focused only on pack-based bitmaps and need
to be updated to disable 'GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP' where
necessary.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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This test is specifically about generating a midx still respecting a
pack-based bitmap file. Generating a MIDX bitmap would confuse the test.
Let's override the 'GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP' variable to
make sure we don't do so.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Generating a MIDX bitmap confuses many of the tests in t5310, which
expect to control whether and how bitmaps are written. Since the
relevant MIDX-bitmap tests here are covered already in t5326, let's just
disable the flag for the whole t5310 script.
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>
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Generating a MIDX bitmap causes tests which repack in a partial clone to
fail because they are missing objects. Missing objects is an expected
component of tests in t0410, so disable this knob altogether. Graceful
degradation when writing a bitmap with missing objects is tested in
t5326.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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This patch introduces a new test, t5326, which tests the basic
functionality of multi-pack bitmaps.
Some trivial behavior is tested, such as:
- Whether bitmaps can be generated with more than one pack.
- Whether clones can be served with all objects in the bitmap.
- Whether follow-up fetches can be served with some objects outside of
the server's bitmap
These use lib-bitmap's tests (which in turn were pulled from t5310), and
we cover cases where the MIDX represents both a single pack and multiple
packs.
In addition, some non-trivial and MIDX-specific behavior is tested, too,
including:
- Whether multi-pack bitmaps behave correctly with respect to the
pack-reuse machinery when the base for some object is selected from
a different pack than the delta.
- Whether multi-pack bitmaps correctly respect the
pack.preferBitmapTips configuration.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Subsequent tests will want to check for the existence of a multi-pack
bitmap which matches the multi-pack-index stored in the pack directory.
The multi-pack bitmap includes the hex checksum of the MIDX it
corresponds to in its filename (for example,
'$packdir/multi-pack-index-<checksum>.bitmap'). As a result, some tests
want a way to learn what '<checksum>' is.
This helper addresses that need by printing the checksum of the
repository's multi-pack-index.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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We'll soon be adding a test script that will cover many of the same
bitmap concepts as t5310, but for MIDX bitmaps. Let's pull out as many
of the applicable tests as we can so we don't have to rewrite them.
There should be no functional change to t5310; we still run the same
operations in the same order.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Write multi-pack bitmaps in the format described by
Documentation/technical/bitmap-format.txt, inferring their presence with
the absence of '--bitmap'.
To write a multi-pack bitmap, this patch attempts to reuse as much of
the existing machinery from pack-objects as possible. Specifically, the
MIDX code prepares a packing_data struct that pretends as if a single
packfile has been generated containing all of the objects contained
within the MIDX.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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This prepares the code in pack-bitmap to interpret the new multi-pack
bitmaps described in Documentation/technical/bitmap-format.txt, which
mostly involves converting bit positions to accommodate looking them up
in a MIDX.
Note that there are currently no writers who write multi-pack bitmaps,
and that this will be implemented in the subsequent commit. Note also
that get_midx_checksum() and get_midx_filename() are made non-static so
they can be called from pack-bitmap.c.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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try_partial_reuse() is used to mark any bits in the beginning of a
bitmap whose objects can be reused verbatim from the pack they came
from.
Currently this function returns void, and signals nothing to the caller
when bits could not be reused. But multi-pack bitmaps would benefit from
having such a signal, because they may try to pass objects which are in
bounds, but from a pack other than the preferred one.
Any extra calls are noops because of a conditional in
reuse_partial_packfile_from_bitmap(), but those loop iterations can be
avoided by letting try_partial_reuse() indicate when it can't accept any
more bits for reuse, and then listening to that signal.
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>
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In a recent commit, pack-objects learned support for the
'pack.preferBitmapTips' configuration. This patch prepares the
multi-pack bitmap code to respect this configuration, too.
The yet-to-be implemented code will find that it is more efficient to
check whether each reference contains a prefix found in the configured
set of values rather than doing an additional traversal.
Implement a function 'bitmap_is_preferred_refname()' which will perform
that check. Its 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>
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A subsequent patch to support reading MIDX bitmaps will be less noisy
after extracting a generic function to fetch the nth OID contained in
the bitmap.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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A subsequent patch to support reading MIDX bitmaps will be less noisy
after extracting a generic function to return how many objects are
contained in a bitmap.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Opening multiple instance of the same MIDX can lead to problems like two
separate packed_git structures which represent the same pack being added
to the repository's object store.
The above scenario can happen because prepare_midx_pack() checks if
`m->packs[pack_int_id]` is NULL in order to determine if a pack has been
opened and installed in the repository before. But a caller can
construct two copies of the same MIDX by calling get_multi_pack_index()
and load_multi_pack_index() since the former manipulates the
object store directly but the latter is a lower-level routine which
allocates a new MIDX for each call.
So if prepare_midx_pack() is called on multiple MIDXs with the same
pack_int_id, then that pack will be installed twice in the object
store's packed_git pointer.
This can lead to problems in, for e.g., the pack-bitmap code, which does
something like the following (in pack-bitmap.c:open_pack_bitmap()):
struct bitmap_index *bitmap_git = ...;
for (p = get_all_packs(r); p; p = p->next) {
if (open_pack_bitmap_1(bitmap_git, p) == 0)
ret = 0;
}
which is a problem if two copies of the same pack exist in the
packed_git list because pack-bitmap.c:open_pack_bitmap_1() contains a
conditional like the following:
if (bitmap_git->pack || bitmap_git->midx) {
/* ignore extra bitmap file; we can only handle one */
warning("ignoring extra bitmap file: %s", packfile->pack_name);
close(fd);
return -1;
}
Avoid this scenario by not letting write_midx_internal() open a MIDX
that isn't also pointed at by the object store. So long as this is the
case, other routines should prefer to open MIDXs with
get_multi_pack_index() or reprepare_packed_git() instead of creating
instances on their own. Because get_multi_pack_index() returns
`r->object_store->multi_pack_index` if it is non-NULL, we'll only have
one instance of a MIDX open at one time, avoiding these problems.
To encourage this, drop the `struct multi_pack_index *` parameter from
`write_midx_internal()`, and rely instead on the `object_dir` to find
(or initialize) the correct MIDX instance.
Likewise, replace the call to `close_midx()` with
`close_object_store()`, since we're about to replace the MIDX with a new
one and should invalidate the object store's memory of any MIDX that
might have existed beforehand.
Note that this now forbids passing object directories that don't belong
to alternate repositories over `--object-dir`, since before we would
have happily opened a MIDX in any directory, but now restrict ourselves
to only those reachable by `r->objects->multi_pack_index` (and alternate
MIDXs that we can see by walking the `next` pointer).
As far as I can tell, supporting arbitrary directories with
`--object-dir` was a historical accident, since even the documentation
says `<alt>` when referring to the value passed to this option.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When fetching refs, we are doing two connectivity checks:
- The first one is done such that we can skip fetching refs in the
case where we already have all objects referenced by the updated
set of refs.
- The second one verifies that we have all objects after we have
fetched objects.
We always execute both connectivity checks, but this is wasteful in case
the first connectivity check already notices that we have all objects
locally available.
Skip the second connectivity check in case we already had all objects
available. This gives us a nice speedup when doing a mirror-fetch in a
repository with about 2.3M refs where the fetching repo already has all
objects:
Benchmark #1: HEAD~: git-fetch
Time (mean ± σ): 30.025 s ± 0.081 s [User: 27.070 s, System: 4.933 s]
Range (min … max): 29.900 s … 30.111 s 5 runs
Benchmark #2: HEAD: git-fetch
Time (mean ± σ): 25.574 s ± 0.177 s [User: 22.855 s, System: 4.683 s]
Range (min … max): 25.399 s … 25.765 s 5 runs
Summary
'HEAD: git-fetch' ran
1.17 ± 0.01 times faster than 'HEAD~: git-fetch'
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The functions `fetch_refs()` and `consume_refs()` must always be called
together such that we first obtain all missing objects and then update
our local refs to match the remote refs. In a subsequent patch, we'll
further require that `fetch_refs()` must always be called before
`consume_refs()` such that it can correctly assert that we have all
objects after the fetch given that we're about to move the connectivity
check.
Make this requirement explicit by merging both functions into a single
`fetch_and_consume_refs()` function.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Refactor `fetch_refs()` code to make it more extendable by explicitly
handling error cases. The refactored code should behave the same.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In order to negotiate a packfile, we need to dereference refs to see
which commits we have in common with the remote. To do so, we first look
up the object's type -- if it's a tag, we peel until we hit a non-tag
object. If we hit a commit eventually, then we return that commit.
In case the object ID points to a commit directly, we can avoid the
initial lookup of the object type by opportunistically looking up the
commit via the commit-graph, if available, which gives us a slight speed
bump of about 2% in a huge repository with about 2.3M refs:
Benchmark #1: HEAD~: git-fetch
Time (mean ± σ): 31.634 s ± 0.258 s [User: 28.400 s, System: 5.090 s]
Range (min … max): 31.280 s … 31.896 s 5 runs
Benchmark #2: HEAD: git-fetch
Time (mean ± σ): 31.129 s ± 0.543 s [User: 27.976 s, System: 5.056 s]
Range (min … max): 30.172 s … 31.479 s 5 runs
Summary
'HEAD: git-fetch' ran
1.02 ± 0.02 times faster than 'HEAD~: git-fetch'
In case this fails, we fall back to the old code which peels the
objects to a commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The object ID iterator used by the connectivity checks returns the next
object ID via an out-parameter and then uses a return code to indicate
whether an item was found. This is a bit roundabout: instead of a
separate error code, we can just return the next object ID directly and
use `NULL` pointers as indicator that the iterator got no items left.
Furthermore, this avoids a copy of the object ID.
Refactor the iterator and all its implementations to return object IDs
directly. This brings a tiny performance improvement when doing a mirror-fetch of a repository with about 2.3M refs:
Benchmark #1: 328dc58b49919c43897240f2eabfa30be2ce32a4~: git-fetch
Time (mean ± σ): 30.110 s ± 0.148 s [User: 27.161 s, System: 5.075 s]
Range (min … max): 29.934 s … 30.406 s 10 runs
Benchmark #2: 328dc58b49919c43897240f2eabfa30be2ce32a4: git-fetch
Time (mean ± σ): 29.899 s ± 0.109 s [User: 26.916 s, System: 5.104 s]
Range (min … max): 29.696 s … 29.996 s 10 runs
Summary
'328dc58b49919c43897240f2eabfa30be2ce32a4: git-fetch' ran
1.01 ± 0.01 times faster than '328dc58b49919c43897240f2eabfa30be2ce32a4~: git-fetch'
While this 1% speedup could be labelled as statistically insignificant,
the speedup is consistent on my machine. Furthermore, this is an end to
end test, so it is expected that the improvement in the connectivity
check itself is more significant.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When updating local refs after the fetch has transferred all objects, we
do an object existence test as a safety guard to avoid updating a ref to
an object which we don't have. We do so via `oid_object_info()`: if it
returns an error, then we know the object does not exist.
One side effect of `oid_object_info()` is that it parses the object's
type, and to do so it must unpack the object header. This is completely
pointless: we don't care for the type, but only want to assert that the
object exists.
Refactor the code to use `repo_has_object_file()`, which both makes the
code's intent clearer and is also faster because it does not unpack
object headers. In a real-world repo with 2.3M refs, this results in a
small speedup when doing a mirror-fetch:
Benchmark #1: HEAD~: git-fetch
Time (mean ± σ): 33.686 s ± 0.176 s [User: 30.119 s, System: 5.262 s]
Range (min … max): 33.512 s … 33.944 s 5 runs
Benchmark #2: HEAD: git-fetch
Time (mean ± σ): 31.247 s ± 0.195 s [User: 28.135 s, System: 5.066 s]
Range (min … max): 30.948 s … 31.472 s 5 runs
Summary
'HEAD: git-fetch' ran
1.08 ± 0.01 times faster than 'HEAD~: git-fetch'
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When updating our local refs based on the refs fetched from the remote,
we need to iterate through all requested refs and load their respective
commits such that we can determine whether they need to be appended to
FETCH_HEAD or not. In cases where we're fetching from a remote with
exceedingly many refs, resolving these refs can be quite expensive given
that we repeatedly need to unpack object headers for each of the
referenced objects.
Speed this up by opportunistically trying to resolve object IDs via the
commit graph. We only do so for any refs which are not in "refs/tags":
more likely than not, these are going to be a commit anyway, and this
lets us avoid having to unpack object headers completely in case the
object is a commit that is part of the commit-graph. This significantly
speeds up mirror-fetches in a real-world repository with
2.3M refs:
Benchmark #1: HEAD~: git-fetch
Time (mean ± σ): 56.482 s ± 0.384 s [User: 53.340 s, System: 5.365 s]
Range (min … max): 56.050 s … 57.045 s 5 runs
Benchmark #2: HEAD: git-fetch
Time (mean ± σ): 33.727 s ± 0.170 s [User: 30.252 s, System: 5.194 s]
Range (min … max): 33.452 s … 33.871 s 5 runs
Summary
'HEAD: git-fetch' ran
1.67 ± 0.01 times faster than 'HEAD~: git-fetch'
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When a repository has at least one alternate, the MIDX belonging to each
alternate is accessed through the `next` pointer on the main object
store's copy of the MIDX. close_midx() didn't bother to close any
of the linked MIDXs. It likewise didn't free the memory pointed to by
`m`, leaving uninitialized bytes with live pointers to them left around
in the heap.
Clean this up by closing linked MIDXs, and freeing up the memory pointed
to by each of them. When callers call close_midx(), then they can
discard the entire linked list of MIDXs and set their pointer to the
head of that list to NULL.
This isn't strictly required for the upcoming patches, but it makes it
much more difficult (though still possible, for e.g., by calling
`close_midx(m->next)` which leaves `m->next` pointing at uninitialized
bytes) to have pointers to uninitialized memory.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In 9218c6a40c (midx: allow marking a pack as preferred, 2021-03-30), the
multi-pack index code learned how to select a pack which all duplicate
objects are selected from. That is, if an object appears in multiple
packs, select the copy in the preferred pack before breaking ties
according to the other rules like pack mtime and readdir() order.
Not specifying a preferred pack can cause serious problems with
multi-pack reachability bitmaps, because these bitmaps rely on having at
least one pack from which all duplicates are selected. Not having such a
pack causes problems with the code in pack-objects to reuse packs
verbatim (e.g., that code assumes that a delta object in a chunk of pack
sent verbatim will have its base object sent from the same pack).
So why does not marking a pack preferred cause problems here? The reason
is roughly as follows:
- Ties are broken (when handling duplicate objects) by sorting
according to midx_oid_compare(), which sorts objects by OID,
preferred-ness, pack mtime, and finally pack ID (more on that
later).
- The psuedo pack-order (described in
Documentation/technical/pack-format.txt under the section
"multi-pack-index reverse indexes") is computed by
midx_pack_order(), and sorts by pack ID and pack offset, with
preferred packs sorting first.
- But! Pack IDs come from incrementing the pack count in
add_pack_to_midx(), which is a callback to
for_each_file_in_pack_dir(), meaning that pack IDs are assigned in
readdir() order.
When specifying a preferred pack, all of that works fine, because
duplicate objects are correctly resolved in favor of the copy in the
preferred pack, and the preferred pack sorts first in the object order.
"Sorting first" is critical, because the bitmap code relies on finding
out which pack holds the first object in the MIDX's pseudo pack-order to
determine which pack is preferred.
But if we didn't specify a preferred pack, and the pack which comes
first in readdir() order does not also have the lowest timestamp, then
it's possible that that pack (the one that sorts first in pseudo-pack
order, which the bitmap code will treat as the preferred one) did *not*
have all duplicate objects resolved in its favor, resulting in breakage.
The fix is simple: pick a (semi-arbitrary, non-empty) preferred pack
when none was specified. This forces that pack to have duplicates
resolved in its favor, and (critically) to sort first in pseudo-pack
order. Unfortunately, testing this behavior portably isn't possible,
since it depends on readdir() order which isn't guaranteed by POSIX.
(Note that multi-pack reachability bitmaps have yet to be implemented;
so in that sense this patch is fixing a bug which does not yet exist.
But by having this patch beforehand, we can prevent the bug from ever
materializing.)
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The soon-to-be-implemented multi-pack bitmap treats object in the first
bit position specially by assuming that all objects in the pack it was
selected from are also represented from that pack in the MIDX. In other
words, the pack from which the first object was selected must also have
all of its other objects selected from that same pack in the MIDX in
case of any duplicates.
But this assumption relies on the fact that there is at least one object
in that pack to begin with; otherwise the object in the first bit
position isn't from a preferred pack, in which case we can no longer
assume that all objects in that pack were also selected from the same
pack.
Guard this assumption by checking the number of objects in the given
preferred pack, and failing if the given pack is empty.
To make sure we can safely perform this check, open any packs which are
contained in an existing MIDX via prepare_midx_pack(). The same is done
for new packs via the add_pack_to_midx() callback, but packs picked up
from a previous MIDX will not yet have these opened.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When writing a new multi-pack index, write_midx_internal() attempts to
clean up any auxiliary files (currently just the MIDX's `.rev` file, but
soon to include a `.bitmap`, too) corresponding to the MIDX it's
replacing.
This step should happen after the new MIDX is written into place, since
doing so beforehand means that the old MIDX could be read without its
corresponding .rev file.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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If using --object-dir to point into an object directory which belongs to
a different repository than the one in the current working directory,
such as:
git init repo
git -C repo ... # add some objects
cd alternate
git multi-pack-index --object-dir ../repo/.git/objects write
the binary will segfault trying to access the object-dir via the repo it
found, but that's not fully initialized. Worse, if we later call
clear_midx_files_ext(), we will use `the_repository` and remove files
out of the wrong object directory.
Fix this by using the given object_dir (or the object directory of
`the_repository` if `--object-dir` wasn't given) to properly to clean up
the *.rev files, avoiding the crash.
Original-patch-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The multi-pack-index command supports working with arbitrary object
directories via the `--object-dir` flag. Though this has historically
worked in arbitrary repositories (including when the command itself was
run outside of a Git repository), this has been somewhat of an accident.
For example, running:
git multi-pack-index write --object-dir=/path/to/repo/objects
outside of a Git repository causes a BUG(). This is because the
top-level `cmd_multi_pack_index()` function stops parsing when it sees
"write", and then fills in the default object directory (the result of
calling `get_object_directory()`) before handing off to
`cmd_multi_pack_index_write()`. But there is no repository to
initialize, and so calling `get_object_directory()` results in a BUG()
(indicating that the current repository is not initialized).
Another case where this doesn't quite work as expected is when operating
in a SHA-256 repository. To see the failure, try this in your shell:
git init --object-format=sha256 repo
git -C repo commit --allow-empty base
git -C repo repack -d
git multi-pack-index --object-dir=$(pwd)/repo/.git/objects write
and observe that we cannot open the `.idx` file in "repo", because the
outermost process assumes that any repository that it works in also uses
the default value of `the_hash_algo` (at the time of writing, SHA-1).
There may be compelling reasons for trying to work around these bugs,
but working in arbitrary `--object-dir`'s is non-standard enough (and
likewise, these bugs prevalent enough) that I don't think any workflows
would be broken by abandoning this behavior.
Accordingly, restrict the `multi-pack-index` builtin to only work when
inside of a Git repository (i.e., its main utility becomes selecting
which alternate to operate in), which avoids both of the bugs above.
(Note that you can still trigger a bug when writing a MIDX in an
alternate which does not use the same object format as the repository
which it is an alternate of, but that is an unrelated bug to this one).
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In both protocol v0 and v2, upload-pack writes one pktline packet per
advertised ref to stdout. That means one or two write(2) syscalls per
ref. This is problematic if these writes become network sends with
high overhead.
This commit changes both send_ref callbacks to use buffered IO using
stdio.
To give an example of the impact: I set up a single-threaded loop that
calls ls-remote (with HTTP and protocol v2) on a local GitLab
instance, on a repository with 11K refs. When I switch from Git
v2.32.0 to this patch, I see a 40% reduction in CPU time for Git, and
65% for Gitaly (GitLab's Git RPC service).
So using buffered IO not only saves syscalls in upload-pack, it also
saves time in things that consume upload-pack's output.
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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This adds three new functions to pkt-line.c: packet_fwrite,
packet_fwrite_fmt and packet_fflush. Besides writing a pktline flush
packet, packet_fflush also flushes the stdio buffer of the stream.
Helped-by: Patrick Steinhardt <ps@pks.im>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Expand the section about namespaces in the documentation of
`transfer.hideRefs` to point out the subtle differences between
`upload-pack` and `receive-pack`.
ffcfb68176 (upload-pack.c: treat want-ref relative to namespace,
2021-07-30) taught `upload-pack` to reject `want-ref`s for hidden refs,
which is now mentioned. It is clarified that at no point the name of a
hidden ref is revealed, but the object id it points to may.
Signed-off-by: Kim Altintop <kim@eagain.st>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When 'upload-pack' runs within the context of a git namespace, treat any
'want-ref' lines the client sends as relative to that namespace.
Also check if the wanted ref is hidden via 'hideRefs'. If it is hidden,
respond with an error as if the ref didn't exist.
Helped-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Kim Altintop <kim@eagain.st>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Assembling a "raw" fetch command to be fed directly to "test-tool serve-v2"
is extracted into a test helper.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Kim Altintop <kim@eagain.st>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In the free_mailmap_entry() code added in 0925ce4d49 (Add map_user()
and clear_mailmap() to mailmap, 2009-02-08) the intent was clearly to
clear the "me" structure, but while we freed parts of the
mailmap_entry structure, we didn't free the structure itself. The same
goes for the "mailmap_info" structure.
This brings the number of SANITIZE=leak failures in t4203-mailmap.sh
down from 50 to 49. Not really progress as far as the number of
failures is concerned, but as far as I can tell this fixes all leaks
in mailmap.c itself. There's still users of it such as builtin/log.c
that call read_mailmap() without a clear_mailmap(), but that's on
them.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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"enum" keyword will be introduced in PHP 8.1.
https://wiki.php.net/rfc/enumerations
Signed-off-by: USAMI Kenta <tadsan@zonu.me>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Commit 7f4075949686 (fast-export: tighten anonymize_mem() interface to
handle only strings, 2020-06-23) changed the interface used in anonymizing
strings, but failed to update the size of annotated tag messages to match
the new anonymized string.
As a result, exporting tags having messages longer than 13 characters
would create output that couldn't be parsed by fast-import,
as the data length indicated was larger than the data output.
Reset the message size when anonymizing, and add a tag with a "long"
message to the test.
Signed-off-by: Tal Kelrich <hasturkun@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Fix a memory leak in a2ba162cda (object-info: support for retrieving
object info, 2021-04-20) which appears to have been based on a
misunderstanding of how the pkt-line.c API works. There is no need to
strdup() input to packet_writer_write(), it's just a printf()-like
format function.
This fixes a potentially large memory leak, since the number of OID
lines the "object-info" call can be arbitrarily large (or a small one
if the request is small).
This makes t5701-git-serve.sh pass again under SANITIZE=leak, as it
did before a2ba162cda2.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Bruno Albuquerque <bga@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When we fail to start a diff command inside a submodule, immediately
exit the routine rather than trying to finish the command and printing
a second message.
Signed-off-by: David Turner <dturner@twosigma.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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If you have ever initialized a submodule, open_submodule will open it.
If you then delete the submodule's worktree directory (but don't
remove it from .gitmodules), git diff --submodule=diff would error out
as it attempted to chdir into the now-deleted working tree directory.
This only matters if the submodules git dir is absorbed. If not, then
we no longer have anywhere to run the diff. But that case does not
trigger this error, because in that case, open_submodule fails, so we
don't resolve a left commit, so we exit early, which is the only thing
we could do.
If absorbed, then we can run the diff from the submodule's absorbed
git dir (.git/modules/sm2). In practice, that's a bit more
complicated, because `git diff` expects to be run from inside a
working directory, not a git dir. So it looks in the config for
core.worktree, and does chdir("../../../sm2"), which is the very dir
that we're trying to avoid visiting because it's been deleted. We
work around this by setting GIT_WORK_TREE (and GIT_DIR) to ".". It is
little weird to set GIT_WORK_TREE to something that is not a working
tree just to avoid an unnecessary chdir, but it works.
Signed-off-by: David Turner <dturner@twosigma.com
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Bring the "commit-graph" command in line with the error output and
general pattern in cmd_multi_pack_index().
Let's test for that output, and also cover the same potential bug as
was fixed in the multi-pack-index command in
88617d11f9d (multi-pack-index: fix potential segfault without
sub-command, 2021-07-19).
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Change the parse_options() invocation in the commit-graph code to
error on unknown leftover argv elements, in addition to the existing
and implicit erroring via parse_options() on unknown options.
We'd already error in cmd_commit_graph() on e.g.:
git commit-graph unknown verify
git commit-graph --unknown verify
But here we're calling parse_options() twice more for the "write" and
"verify" subcommands. We did not do the same checking for leftover
argv elements there. As a result we'd silently accept garbage in these
subcommands, let's not do that.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Rather than guarding all of the !argc with an additional "if" arm
let's do an early goto to "usage". This also makes it clear that
"save_commit_buffer" is not needed in this case.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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