Avoid calling 'cache_tree_update()' when doing so would be redundant.
* vd/skip-cache-tree-update:
rebase: use 'skip_cache_tree_update' option
read-tree: use 'skip_cache_tree_update' option
reset: use 'skip_cache_tree_update' option
unpack-trees: add 'skip_cache_tree_update' option
cache-tree: add perf test comparing update and prime
Update the credential-cache documentation to provide a more realistic
example.
* mh/increase-credential-cache-timeout:
Documentation: increase example cache timeout to 1 hour
`git rebase --update-refs` would delete references when all `update-ref`
commands in the sequencer were removed, which has been corrected.
* vd/update-refs-delete:
rebase --update-refs: avoid unintended ref deletion
"git repack" learns to send cruft objects out of the way into
packfiles outside the repository.
* tb/repack-expire-to:
builtin/repack.c: implement `--expire-to` for storing pruned objects
builtin/repack.c: write cruft packs to arbitrary locations
builtin/repack.c: pass "cruft_expiration" to `write_cruft_pack`
builtin/repack.c: pass "out" to `prepare_pack_objects`
Makefile comments updates and reordering to clarify knobs used to
choose SHA implementations.
* ab/sha-makefile-doc:
Makefile: discuss SHAttered in *_SHA{1,256} discussion
Makefile: document default SHA-1 backend on OSX
Makefile & test-tool: replace "DC_SHA1" variable with a "define"
Makefile: document SHA-1 and SHA-256 default and selection order
Makefile: document default SHA-256 backend
Makefile: rephrase the discussion of *_SHA1 knobs
Makefile: create and use sections for "define" flag listing
Makefile: correct DC_SHA1 documentation
INSTALL: remove discussion of SHA-1 backends
Makefile: always (re)set DC_SHA1 on fallback
Various test updates.
* ab/misc-hook-submodule-run-command:
run-command tests: test stdout of run_command_parallel()
submodule tests: reset "trace.out" between "grep" invocations
hook tests: fix redirection logic error in 96e7225b31
Add trace2 counters to the region to clear skip worktree bits in a
sparse checkout.
* al/trace2-clearing-skip-worktree:
index: raise a bug if the index is materialised more than once
index: add trace2 region for clear skip worktree
It was previously unclear how unrecognised attributes are handled.
Signed-off-by: M Hickford <mirth.hickford@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Remotes are considered "promisor" if extensions.partialClone and some
other configuration variables are set. The casing for this in
Documentation/technical/repository-version.txt is not proper and may
cause confusion. This change corrects this casing.
Signed-off-by: Kousik Sanagavarapu <five231003@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Enable the 'skip_cache_tree_update' option in both 'do_reset()'
('sequencer.c') and 'reset_head()' ('reset.c'). Both of these callers invoke
'prime_cache_tree()' after 'unpack_trees()', so we can remove an unnecessary
cache tree rebuild by skipping 'cache_tree_update()'.
When testing with 'p3400-rebase.sh' and 'p3404-rebase-interactive.sh', the
performance change of this update was negligible, likely due to the
operation being dominated by more expensive operations (like checking out
trees). However, since the change doesn't harm performance, it's worth
keeping this 'unpack_trees()' usage consistent with others that subsequently
invoke 'prime_cache_tree()'.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
When running 'read-tree' with a single tree and no prefix,
'prime_cache_tree()' is called after the tree is unpacked. In that
situation, skip a redundant call to 'cache_tree_update()' in
'unpack_trees()' by enabling the 'skip_cache_tree_update' unpack option.
Removing the redundant cache tree update provides a substantial performance
improvement to 'git read-tree <tree-ish>', as shown by a test added to
'p0006-read-tree-checkout.sh':
Test before after
----------------------------------------------------------------------
read-tree br_ballast_plus_1 3.94(1.80+1.57) 3.00(1.14+1.28) -23.9%
Note that the 'read-tree' in 't1022-read-tree-partial-clone.sh' is updated
to read two trees, rather than one. The test was first introduced in
d3da223f22 (cache-tree: prefetch in partial clone read-tree, 2021-07-23) to
exercise the 'cache_tree_update()' code path, as used in 'git merge'. Since
this patch drops the call to 'cache_tree_update()' in single-tree 'git
read-tree', change the test to use the two-tree variant so that
'cache_tree_update()' is called as intended.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Enable the 'skip_cache_tree_update' option in the variants that call
'prime_cache_tree()' after 'unpack_trees()' (specifically, 'git reset
--mixed' and 'git reset --hard'). This avoids redundantly rebuilding the
cache tree in both 'cache_tree_update()' at the end of 'unpack_trees()' and
in 'prime_cache_tree()', resulting in a small (but consistent) performance
improvement. From the newly-added 'p7102-reset.sh' test:
Test before after
--------------------------------------------------------------------
7102.1: reset --hard (...) 2.11(0.40+1.54) 1.97(0.38+1.47) -6.6%
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Add (disabled by default) option to skip the 'cache_tree_update()' at the
end of 'unpack_trees()'. In many cases, this cache tree update is redundant
because the caller of 'unpack_trees()' immediately follows it with
'prime_cache_tree()', rebuilding the entire cache tree from scratch. While
these operations aren't the most expensive part of operations like 'git
reset', the duplicate calls still create a minor unnecessary slowdown.
Introduce an option for callers to skip the 'cache_tree_update()' in
'unpack_trees()' if it is redundant (that is, if 'prime_cache_tree()' is
called afterwards). At the moment, no 'unpack_trees()' callers use the new
option; they will be updated in subsequent patches.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Add a performance test comparing the execution times of 'prime_cache_tree()'
and 'cache_tree_update(_, WRITE_TREE_SILENT | WRITE_TREE_REPAIR)'. The goal
of comparing these two is to identify which is the faster method for
rebuilding an invalid cache tree, ultimately to remove one when both are
(reundantly) called in immediate succession.
Both methods are fast, so the new tests in 'p0090-cache-tree.sh' must call
each tested function multiple times to ensure the reported times (to 0.01s
resolution) convey the differences between them.
The tests compare the timing of a 'test-tool cache-tree' run as a no-op (to
capture a baseline for the overhead associated with running the tool),
'cache_tree_update()', and 'prime_cache_tree()' on four scenarios:
- A completely valid cache tree
- A cache tree with 2 invalid paths
- A cache tree with 50 invalid paths
- A completely empty cache tree
Example results:
Test this tree
-----------------------------------------------------------
0090.2: no-op, clean 1.27(0.48+0.52)
0090.3: prime_cache_tree, clean 2.02(0.83+0.85)
0090.4: cache_tree_update, clean 1.30(0.49+0.54)
0090.5: no-op, invalidate 2 1.29(0.48+0.54)
0090.6: prime_cache_tree, invalidate 2 1.98(0.81+0.83)
0090.7: cache_tree_update, invalidate 2 2.12(0.94+0.86)
0090.8: no-op, invalidate 50 1.32(0.50+0.55)
0090.9: prime_cache_tree, invalidate 50 2.10(0.86+0.89)
0090.10: cache_tree_update, invalidate 50 2.35(1.14+0.90)
0090.11: no-op, empty 1.33(0.50+0.54)
0090.12: prime_cache_tree, empty 2.04(0.84+0.87)
0090.13: cache_tree_update, empty 2.51(1.27+0.92)
These timings show that, while 'cache_tree_update()' is faster when the
cache tree is completely valid, it is equal to or slower than
'prime_cache_tree()' when there are any invalid paths. Since the redundant
calls are mostly in scenarios where the cache tree will be at least
partially invalid (e.g., 'git reset --hard'), 'prime_cache_tree()' will
likely perform better than 'cache_tree_update()' in typical cases.
Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
When deleting a branch, "git branch -d" has a safety check that ensures
the branch is merged to its upstream (if any), or to HEAD. To do that,
naturally we try to resolve HEAD to a commit object. If we're on an
orphan branch (i.e., HEAD points to a branch that does not yet exist),
that will fail, and we'll bail with an error:
$ git branch -d to-delete
fatal: Couldn't look up commit object for HEAD
This usually isn't that big of a deal. The deletion would fail anyway,
since the branch isn't merged to HEAD, and you'd need to use "-D" (or
"-f"). And doing so skips the HEAD resolution, courtesy of 67affd5173
(git-branch -D: make it work even when on a yet-to-be-born branch,
2006-11-24).
But there are still two problems:
1. The error message isn't very helpful. We should give the usual "not
fully merged" message, which points the user at "branch -D". That
was a problem even back in 67affd5173.
2. Even without a HEAD, these days it's still possible for the
deletion to succeed. After 67affd5173, commit 99c419c915 (branch
-d: base the "already-merged" safety on the branch it merges with,
2009-12-29) made it OK to delete a branch if it is merged to its
upstream.
We can fix both by removing the die() in delete_branches() completely,
leaving head_rev NULL in this case. It's tempting to stop there, as it
appears at first glance that the rest of the code does the right thing
with a NULL. But sadly, it's not quite true.
We end up feeding the NULL to repo_is_descendant_of(). In the
traditional code path there, we call repo_in_merge_bases_many(). It
feeds the NULL to repo_parse_commit(), which is smart enough to return
an error, and we immediately return "no, it's not a descendant".
But there's an alternate code path: if we have a commit graph with
generation numbers, we end up in can_all_from_reach(), which does
eventually try to set a flag on the NULL commit and segfaults.
So instead, we'll teach the local branch_merged() helper to treat a NULL
as "not merged". This would be a little more elegant in in_merge_bases()
itself, but that function is called in a lot of places, and it's not
clear that quietly returning "not merged" is the right thing everywhere
(I'd expect in many cases, feeding a NULL is a sign of a bug).
There are four tests here:
a. The first one confirms that deletion succeeds with an orphaned HEAD
when the branch is merged to its upstream. This is case (2) above.
b. Same, but with commit graphs enabled. Even if it is merged to
upstream, we still check head_rev so that we can say "deleting
because it's merged to upstream, even though it's not merged to
HEAD". Without the second hunk in branch_merged(), this test would
segfault in can_all_from_reach().
c. The third one confirms that we correctly say "not merged to HEAD"
when we can't resolve HEAD, and reject the deletion.
d. Same, but with commit graphs enabled. Without the first hunk in
branch_merged(), this one would segfault.
Reported-by: Martin von Zweigbergk <martinvonz@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Previously, the example *decreased* the cache timeout compared to the
default, making it less user friendly.
Instead, nudge users to make cache more usable. Many users choose
store over cache.
https://lore.kernel.org/git/CAGJzqskRYN49SeS8kSEN5-vbB_Jt1QvAV9QhS6zNuKh0u8wxPQ@mail.gmail.com/
The default timeout remains 15 minutes. A stronger nudge would
be to increase that.
Signed-off-by: M Hickford <mirth.hickford@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Simplify the run-command API.
* rs/no-more-run-command-v:
replace and remove run_command_v_opt()
replace and remove run_command_v_opt_cd_env_tr2()
replace and remove run_command_v_opt_tr2()
replace and remove run_command_v_opt_cd_env()
use child_process members "args" and "env" directly
use child_process member "args" instead of string array variable
sequencer: simplify building argument list in do_exec()
bisect--helper: factor out do_bisect_run()
bisect: simplify building "checkout" argument list
am: simplify building "show" argument list
run-command: fix return value comment
merge: remove always-the-same "verbose" arguments
"git archive" mistakenly complained twice about a missing executable,
which has been corrected.
* rs/archive-filter-error-once:
archive-tar: report filter start error only once
A redundant diagnostic message is dropped from test_path_is_missing().
* ma/drop-redundant-diagnostic:
test-lib-functions: drop redundant diagnostic print
Various tests exercising the transfer.credentialsInUrl configuration
are taught to avoid making requests which require resolving localhost
to reduce CI-flakiness.
* jk/ref-filter-parsing-bugs:
ref-filter: fix parsing of signatures with CRLF and no body
ref-filter: fix parsing of signatures without blank lines
The glossary entries for "commit-graph file" and "reachability
bitmap" have been added.
* po/glossary-around-traversal:
glossary: add reachability bitmap description
glossary: add "commit graph" description
doc: use 'object database' not ODB or abbreviation
doc: use "commit-graph" hyphenation consistently
The adjust_shared_perm() helper function learned to refrain from
setting the "g+s" bit on directories when it is not necessary.
* jc/set-gid-bit-less-aggressively:
adjust_shared_perm(): leave g+s alone when the group does not matter
Enable gc.cruftpacks by default for those who opt into
feature.experimental setting.
* es/mark-gc-cruft-as-experimental:
config: let feature.experimental imply gc.cruftPacks=true
gc: add tests for --cruft and friends
Git asks for a "password", but the user might use a
personal access token or OAuth access token instead.
Example:
Password for 'https://AzureDiamond@github.com':
Signed-off-by: M Hickford <mirth.hickford@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Have the REV_INFO_INIT macro added in [1] declare more members of
"struct rev_info" that we can initialize statically, and have
repo_init_revisions() do so with the memcpy(..., &blank) idiom
introduced in [2].
As the comment for the "REV_INFO_INIT" macro notes this still isn't
sufficient to initialize a "struct rev_info" for use yet. But we are
getting closer to that eventual goal.
Even though we can't fully initialize a "struct rev_info" with
REV_INFO_INIT it's useful for readability to clearly separate those
things that we can statically initialize, and those that we can't.
This change could replace the:
list_objects_filter_init(&revs->filter);
In the repo_init_revisions() with this line, at the end of the
REV_INFO_INIT deceleration in revisions.h:
.filter = LIST_OBJECTS_FILTER_INIT, \
But doing so would produce a minor conflict with an outstanding
topic[3]. Let's skip that for now. I have follow-ups to initialize
more of this statically, e.g. changes to get rid of grep_init(). We
can initialize more members with the macro in a future series.
1. f196c1e908 (revisions API users: use release_revisions() needing
REV_INFO_INIT, 2022-04-13)
2. 5726a6b401 (*.c *_init(): define in terms of corresponding *_INIT
macro, 2021-07-01)
3. https://lore.kernel.org/git/265b292ed5c2de19b7118dfe046d3d9d932e2e89.1667901510.git.ps@pks.im/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
The old version we currently use runs in node.js v12.x, which is being
deprecated in GitHub Actions. The new version uses node.js v16.x.
Incidentally, this also avoids the warning about the deprecated
`::set-output::` workflow command because the newer version of the
`github-script` Action uses the recommended new way to specify outputs.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Let's mention the SHAttered attack and more generally why we use the
sha1collisiondetection backend by default, and note that for SHA-256
the user should feel free to pick any of the supported backends as far
as hashing security is concerned.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Since [1] the default SHA-1 backend on OSX has been
APPLE_COMMON_CRYPTO. Per [2] we'll skip using it on anything older
than Mac OS X 10.4 "Tiger"[3].
When "DC_SHA1" was made the default in [4] this interaction between it
and APPLE_COMMON_CRYPTO seems to have been missed in. Ever since
DC_SHA1 was "made the default" we've still used Apple's CommonCrypto
instead of sha1collisiondetection on modern versions of Darwin and
OSX.
1. 61067954ce (cache.h: eliminate SHA-1 deprecation warnings on Mac
OS X, 2013-05-19)
2. 9c7a0beee0 (config.mak.uname: set NO_APPLE_COMMON_CRYPTO on older
systems, 2014-08-15)
3. We could probably drop "NO_APPLE_COMMON_CRYPTO", as nobody's likely
to care about such on old version of OSX anymore. But let's leave that
for now.
4. e6b07da278 (Makefile: make DC_SHA1 the default, 2017-03-17)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Address the root cause of technical debt we've been carrying since
sha1collisiondetection was made the default in [1]. In a preceding
commit we narrowly fixed a bug where the "DC_SHA1" variable would be
unset (in combination with "NO_APPLE_COMMON_CRYPTO=" on OSX), even
though we had the sha1collisiondetection library enabled.
But the only reason we needed to have such a user-exposed knob went
away with [1], and it's been doing nothing useful since then. We don't
care if you define DC_SHA1=*, we only care that you don't ask for any
other SHA-1 implementation. If it turns out that you didn't, we'll use
sha1collisiondetection, whether you had "DC_SHA1" set or not.
As a result of this being confusing we had e.g. [2] for cmake and the
recent [3] for ci/lib.sh setting "DC_SHA1" explicitly, even though
this was always a NOOP.
A much simpler way to do this is to stop having the Makefile and
CMakeLists.txt set "DC_SHA1" to be picked up by the test-lib.sh, let's
instead add a trivial "test-tool sha1-is-sha1dc". It returns zero if
we're using sha1collisiondetection, non-zero otherwise.
1. e6b07da278 (Makefile: make DC_SHA1 the default, 2017-03-17)
2. c4b2f41b5f (cmake: support for testing git with ctest, 2020-06-26)
3. 1ad5c3df35 (ci: use DC_SHA1=YesPlease on osx-clang job for CI,
2022-10-20)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
For the *_SHA1 and *_SHA256 flags we've discussed the various flags,
but not the fact that when you define multiple flags we'll pick one.
Which one we pick depends on the order they're listed in the Makefile,
which differed from the order we discussed them in this documentation.
Let's be explicit about how we select these, and re-arrange the
listings so that they're listed in the priority order we've picked.
I'd personally prefer that the selection was more explicit, and that
we'd error out if conflicting flags were provided, but per the
discussion downhtread of[1] the consensus was to keep theses semantics.
This behavior makes it easier to e.g. integrate with autoconf-like
systems, where the configuration can provide everything it can
support, and Git is tasked with picking the first one it prefers.
1. https://lore.kernel.org/git/220710.86mtdh81ty.gmgdl@evledraar.gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Since 27dc04c545 (sha256: add an SHA-256 implementation using
libgcrypt, 2018-11-14) we've claimed to support a BLK_SHA256 flag, but
there's no such SHA-256 backend.
Instead we fall back on adding "sha256/block/sha256.o" to "LIB_OBJS"
and adding "-DSHA256_BLK" to BASIC_CFLAGS.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
In the preceding commit the discussion of the *_SHA1 knobs was left
as-is to benefit from a smaller diff, but since we're changing these
let's use the same phrasing we use for most other knobs. E.g. "define
X", not "define X environment variable", and get rid of the "when
running make to link with" entirely.
Furthermore the discussion of DC_SHA1* options is now under a "Options
for the sha1collisiondetection implementation" heading, so we don't
need to clarify that these options go along with DC_SHA1=Y, so let's
rephrase them accordingly.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Since the "Define ..." template of comments at the top of the Makefile
was started in 5bdac8b326 ([PATCH] Improve the compilation-time
settings interface, 2005-07-29) we've had a lot more flags added,
including flags that come in "groups". Not having any obvious
structure to the >500 line comment at the top of the Makefile has made
it hard to follow.
This change is almost entirely a move-only change, the two paragraphs
at the start of the first two sections are new, and so are the added
sections themselves, but other than that no lines are changed, only
moved.
We now list Makefile-only flags at the start, followed by stand-alone
flags, and then cover "optional library" flags in their respective
groups, followed by SHA-1 and SHA-256 flags, and finally
DEVELOPER-specific flags.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
The claim that DC_SHA1 takes priority over other *_SHA1 knobs was true
when it was added in [1], But that hasn't been the case since it was
made the fallback default in [2].
We should be making it not only the default, but something that takes
priority over other *_SHA1 knobs, but that's outside the scope of this
change. For now let's correct the documentation to match reality.
Let's also remove the "unconditionally enable" wording, per the above
the enabling of "DC_SHA1" is conditional on these other flags.
The "Define DC_SHA1" here is also a lie, actually it's "we don't care
if you define DC_SHA1, just don't define anything else", but that's a
more general issue that'll be addressed in a subsequent commit. Let's
first stop pretending that this setting (which we actually don't even
use) takes priority over anything else.
1. 8325e43b82 (Makefile: add DC_SHA1 knob, 2017-03-16)
2. e6b07da278 (Makefile: make DC_SHA1 the default, 2017-03-17)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
The claim that OpenSSL is the default SHA-1 backend hasn't been true
since e6b07da278 (Makefile: make DC_SHA1 the default, 2017-03-17),
but more importantly tweaking the SHA-1 backend isn't something that's
common enough to warrant discussing in the INSTALL document, so let's
remove this paragraph.
This discussion was originally added in c538d2d34a (Add some
installation notes in INSTALL, 2005-06-17) when tweaking the default
backend was more common. The current wording was added in
5beb577db8 (INSTALL: Describe dependency knobs from Makefile,
2009-09-10).
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Fix an edge case introduced in in e6b07da278 (Makefile: make DC_SHA1
the default, 2017-03-17), when DC_SHA1 was made the default fallback
we started unconditionally adding to BASIC_CFLAGS and LIB_OBJS, so
we'd use the sha1collisiondetection by default.
But the "DC_SHA1" variable remained unset, so e.g.:
make test DC_SHA1= T=t0013*.sh
Would skip the sha1collisiondetection tests, as we'd write
"DC_SHA1=''" to "GIT-BUILD-OPTIONS", but if we manually removed that
test prerequisite we'd pass the test (which we couldn't if we weren't
using sha1collisiondetection).
So let's have the fallback assignment use the 'override' directive
instead of the ":=" simply expanded variable introduced in
e6b07da278. In this case we explicitly want to override the user's
choice.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Taylor Blau
Vlad-Stefan Harbuz
M Hickford
Kousik Sanagavarapu
Victoria Dye
Jeff King
Ævar Arnfjörð Bjarmason
Johannes Schindelin