Introduce an optional configuration to allow the trailing hash that
protects the index file from bit flipping.
* ds/omit-trailing-hash-in-index:
features: feature.manyFiles implies fast index writes
test-lib-functions: add helper for trailing hash
read-cache: add index.skipHash config option
hashfile: allow skipping the hash function
The logic to see if we are using the "cone" mode by checking the
sparsity patterns has been tightened to avoid mistaking a pattern
that names a single file as specifying a cone.
* ws/single-file-cone:
dir: check for single file cone patterns
"git diff --relative" did not mix well with "git diff --ext-diff",
which has been corrected.
* jk/ext-diff-with-relative:
diff: drop "name" parameter from prepare_temp_file()
diff: clean up external-diff argv setup
diff: use filespec path to set up tempfiles for ext-diff
Conditionally skip the pre-applypatch and applypatch-msg hooks when
applying patches with 'git am'.
* tr/am--no-verify:
am: allow passing --no-verify flag
Test fixes.
* es/t1509-root-fixes:
t1509: facilitate repeated script invocations
t1509: make "setup" test more robust
t1509: fix failing "root work tree" test due to owner-check
CI updates. We probably want a clean-up to move the long shell
script embedded in yaml file into a separate file, but that can
come later.
* cw/ci-whitespace:
ci (check-whitespace): move to actions/checkout@v3
ci (check-whitespace): add links to job output
ci (check-whitespace): suggest fixes for errors
Use `git diff --no-index` as a test_cmp on Windows.
We'd probably need to revisit "do we really want to, and have to,
lose CRLF vs LF?" later, at which time we may be able to further
clean this up by replacing "git diff --no-index" with "diff -u".
* js/drop-mingw-test-cmp:
tests(mingw): avoid very slow `mingw_test_cmp`
Fix typos in code comments which repeat various words. Most of the
cases are simple in that they repeat a word that usually cannot be
repeated in a grammatically correct sentence. Just remove the
incorrectly duplicated word in these cases and rewrap text, if needed.
A tricky case is usage of "that that", which is sometimes grammatically
correct. However, an instance of this in "t7527-builtin-fsmonitor.sh"
doesn't need two words "that", because there is only one daemon being
discussed, so replace the second "that" with "the".
Reword code comment "entries exist on on-disk index" in function
update_one in file cache-tree.c, by replacing incorrect preposition "on"
with "in".
Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The recent addition of the index.skipHash config option allows index
writes to speed up by skipping the hash computation for the trailing
checksum. This is particularly critical for repositories with many files
at HEAD, so add this config option to two cases where users in that
scenario may opt-in to such behavior:
1. The feature.manyFiles config option enables some options that are
helpful for repositories with many files at HEAD.
2. 'scalar register' and 'scalar reconfigure' set config options that
optimize for large repositories.
In both of these cases, set index.skipHash=true to gain this
speedup. Add tests that demonstrate the proper way that
index.skipHash=true can override feature.manyFiles=true.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It can be helpful to check that a file format with a trailing hash has a
specific hash in the final bytes of a written file. This is made more
apparent by recent changes that allow skipping the hash algorithm and
writing a null hash at the end of the file instead.
Add a new test_trailing_hash helper and use it in t1600 to verify that
index.skipHash=true really does skip the hash computation, since
'git fsck' does not actually verify the hash. This confirms that when
the config is disabled explicitly in a super project but enabled in a
submodule, then the use of repo_config_get_bool() loads config from the
correct repository in the case of 'git add'. There are other cases where
istate->repo is NULL and thus this config is loaded instead from
the_repository, but that's due to many different code paths initializing
index_state structs in their own way.
Keep the 'git fsck' call to ensure that any potential future change to
check the index hash does not cause an error in this case.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous change allowed skipping the hashing portion of the
hashwrite API, using it instead as a buffered write API. Disabling the
hashwrite can be particularly helpful when the write operation is in a
critical path.
One such critical path is the writing of the index. This operation is so
critical that the sparse index was created specifically to reduce the
size of the index to make these writes (and reads) faster.
This trade-off between file stability at rest and write-time performance
is not easy to balance. The index is an interesting case for a couple
reasons:
1. Writes block users. Writing the index takes place in many user-
blocking foreground operations. The speed improvement directly
impacts their use. Other file formats are typically written in the
background (commit-graph, multi-pack-index) or are super-critical to
correctness (pack-files).
2. Index files are short lived. It is rare that a user leaves an index
for a long time with many staged changes. Outside of staged changes,
the index can be completely destroyed and rewritten with minimal
impact to the user.
Following a similar approach to one used in the microsoft/git fork [1],
add a new config option (index.skipHash) that allows disabling this
hashing during the index write. The cost is that we can no longer
validate the contents for corruption-at-rest using the trailing hash.
[1] 21fed2d914
We load this config from the repository config given by istate->repo,
with a fallback to the_repository if it is not set.
While older Git versions will not recognize the null hash as a special
case, the file format itself is still being met in terms of its
structure. Using this null hash will still allow Git operations to
function across older versions.
The one exception is 'git fsck' which checks the hash of the index file.
This used to be a check on every index read, but was split out to just
the index in a33fc72fe9 (read-cache: force_verify_index_checksum,
2017-04-14) and released first in Git 2.13.0. Document the versions that
relaxed these restrictions, with the optimistic expectation that this
change will be included in Git 2.40.0.
Here, we disable this check if the trailing hash is all zeroes. We add a
warning to the config option that this may cause undesirable behavior
with older Git versions.
As a quick comparison, I tested 'git update-index --force-write' with
and without index.skipHash=true on a copy of the Linux kernel
repository.
Benchmark 1: with hash
Time (mean ± σ): 46.3 ms ± 13.8 ms [User: 34.3 ms, System: 11.9 ms]
Range (min … max): 34.3 ms … 79.1 ms 82 runs
Benchmark 2: without hash
Time (mean ± σ): 26.0 ms ± 7.9 ms [User: 11.8 ms, System: 14.2 ms]
Range (min … max): 16.3 ms … 42.0 ms 69 runs
Summary
'without hash' ran
1.78 ± 0.76 times faster than 'with hash'
These performance benefits are substantial enough to allow users the
ability to opt-in to this feature, even with the potential confusion
with older 'git fsck' versions.
Test this new config option, both at a command-line level and within a
submodule. The confirmation is currently limited to confirm that 'git
fsck' does not complain about the index. Future updates will make this
test more robust.
It is critical that this test is placed before the test_index_version
tests, since those tests obliterate the .git/config file and hence lose
the setting from GIT_TEST_DEFAULT_HASH, if set.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The hashfile API is useful for generating files that include a trailing
hash of the file's contents up to that point. Using such a hash is
helpful for verifying the file for corruption-at-rest, such as a faulty
drive causing flipped bits.
Git's index file includes this trailing hash, so it uses a 'struct
hashfile' to handle the I/O to the file. This was very convenient to
allow using the hashfile methods during these operations.
However, hashing the file contents during write comes at a performance
penalty. It's slower to hash the bytes on their way to the disk than
without that step. This problem is made worse by the replacement of
hardware-accelerated SHA1 computations with the software-based sha1dc
computation.
This write cost is significant, and the checksum capability is likely
not worth that cost for such a short-lived file. The index is rewritten
frequently and the only time the checksum is checked is during 'git
fsck'. Thus, it would be helpful to allow a user to opt-out of the hash
computation.
We first need to allow Git to opt-out of the hash computation in the
hashfile API. The buffered writes of the API are still helpful, so it
makes sense to make the change here.
Introduce a new 'skip_hash' option to 'struct hashfile'. When set, the
update_fn and final_fn members of the_hash_algo are skipped. When
finalizing the hashfile, the trailing hash is replaced with the null
hash.
This use of a trailing null hash would be desireable in either case,
since we do not want to special case a file format to have a different
length depending on whether it was hashed or not. When the final bytes
of a file are all zero, we can infer that it was written without
hashing, and thus that verification is not available as a check for file
consistency. This also means that we could easily toggle hashing for any
file format we desire.
A version of this patch has existed in the microsoft/git fork since
2017 [1] (the linked commit was rebased in 2018, but the original dates
back to January 2017). Here, the change to make the index use this fast
path is delayed until a later change.
[1] 21fed2d914
Co-authored-by: Kevin Willford <kewillf@microsoft.com>
Signed-off-by: Kevin Willford <kewillf@microsoft.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The prepare_temp_file() function takes a diff_filespec as well as a
filename. But it is almost certainly an error to pass in a name that
isn't the filespec's "path" parameter, since that is the only thing that
reliably tells us how to find the content (and indeed, this was the
source of a recently-fixed bug).
So let's drop the redundant "name" parameter and just use one->path
throughout the function. This simplifies the interface a little bit, and
makes it impossible for calling code to get it wrong.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since the previous commit, setting up the tempfile for an external diff
uses df->path from the diff_filespec, rather than the logical name. This
means add_external_diff_name() does not need to take a "name" parameter
at all, and we can drop it. And that in turn lets us simplify the
conditional for handling renames (when the "other" name is non-NULL).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we're going to run an external diff, we have to make the contents
of the pre- and post-images available either by dumping them to a
tempfile, or by pointing at a valid file in the worktree. The logic of
this is all handled by prepare_temp_file(), and we just pass in the
filename and the diff_filespec.
But there's a gotcha here. The "filename" we have is a logical filename
and not necessarily a path on disk or in the repository. This matters in
at least one case: when using "--relative", we may have a name like
"foo", even though the file content is found at "subdir/foo". As a
result, we look for the wrong path, fail to find "foo", and claim that
the file has been deleted (passing "/dev/null" to the external diff,
rather than the correct worktree path).
We can fix this by passing the pathname from the diff_filespec, which
should always be a full repository path (and that's what we want even if
reusing a worktree file, since we're always operating from the top-level
of the working tree).
The breakage seems to go all the way back to cd676a5136 (diff
--relative: output paths as relative to the current subdirectory,
2008-02-12). As far as I can tell, before then "name" would always have
been the same as the filespec's "path".
There are two related cases I looked at that aren't buggy:
1. the only other caller of prepare_temp_file() is run_textconv(). But
it always passes the filespec's path field, so it's OK.
2. I wondered if file renames/copies might cause similar confusion.
But they don't, because run_external_diff() receives two names in
that case: "name" and "other", which correspond to the two sides of
the diff. And we did correctly pass "other" when handling the
post-image side. Barring the use of "--relative", that would always
match "two->path", the path of the second filespec (and the rename
destination).
So the only bug is just the interaction with external diff drivers and
--relative.
Reported-by: Carl Baldwin <carl@ecbaldwin.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 70b9c10373 (bundle-uri client: add helper for testing server,
2022-12-22) added a cmd_ls_remote() function which contains "uploadpack"
and "server_options" variables. Neither of these variables is ever
modified after being initialized, so the code to handle non-NULL and
non-empty values is impossible to reach.
While in theory we might add command-line parsing to set these, let's
drop the dead code for now in the name of cleanliness. It's easy enough
to add it back later if need be.
Noticed by Coverity.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Stop using "git --super-prefix" and narrow the scope of its use to
the submodule--helper.
* ab/no-more-git-global-super-prefix:
read-tree: add "--super-prefix" option, eliminate global
submodule--helper: convert "{update,clone}" to their own "--super-prefix"
submodule--helper: convert "status" to its own "--super-prefix"
submodule--helper: convert "sync" to its own "--super-prefix"
submodule--helper: convert "foreach" to its own "--super-prefix"
submodule--helper: don't use global --super-prefix in "absorbgitdirs"
submodule.c & submodule--helper: pass along "super_prefix" param
read-tree + fetch tests: test failing "--super-prefix" interaction
submodule absorbgitdirs tests: add missing "Migrating git..." tests
Fix to a small regression in 2.38 days.
* ab/bundle-wo-args:
bundle <cmd>: have usage_msg_opt() note the missing "<file>"
builtin/bundle.c: remove superfluous "newargc" variable
bundle: don't segfault on "git bundle <subcmd>"
Even in a repository with promisor remote, it is useless to
attempt to lazily attempt fetching an object that is expected to be
commit, because no "filter" mode omits commit objects. Take
advantage of this assumption to fail fast on errors.
* jt/avoid-lazy-fetch-commits:
commit: don't lazy-fetch commits
object-file: emit corruption errors when detected
object-file: refactor map_loose_object_1()
object-file: remove OBJECT_INFO_IGNORE_LOOSE
'cat-file' gains mailmap support for its '--batch-check' and '-s'
options.
* sa/cat-file-mailmap--batch-check:
cat-file: add mailmap support to --batch-check option
cat-file: add mailmap support to -s option
The git-am --no-verify flag is analogous to the same flag passed to
git-commit. It bypasses the pre-applypatch and applypatch-msg hooks
if they are enabled.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The sparse checkout documentation states that the cone mode pattern set
is limited to patterns that either recursively include directories or
patterns that match all files in a directory. In the sparse checkout
file, the former manifest in the form:
/A/B/C/
while the latter become a pair of patterns either in the form:
/A/B/
!/A/B/*/
or in the special case of matching the toplevel files:
/*
!/*/
The 'add_pattern_to_hashsets()' function contains checks which serve to
disable cone-mode when non-cone patterns are encountered. However, these
do not catch when the pattern list attempts to match a single file or
directory, e.g. a pattern in the form:
/A/B/C
This causes sparse-checkout to exhibit unexpected behaviour when such a
pattern is in the sparse-checkout file and cone mode is enabled.
Concretely, with the pattern like the above, sparse-checkout, in
non-cone mode, will only include the directory or file located at
'/A/B/C'. However, with cone mode enabled, sparse-checkout will instead
just manifest the toplevel files but not any file located at '/A/B/C'.
Relatedly, issues occur when supplying the same kind of filter when
partial cloning with '--filter=sparse:oid=<oid>'. 'upload-pack' will
correctly just include the objects that match the non-cone pattern
matching. Which means that checking out the newly cloned repo with the
same filter, but with cone mode enabled, fails due to missing objects.
To fix these issues, add a cone mode pattern check that asserts that
every pattern is either a directory match or the pattern '/*'. Add a
test to verify the new pattern check and modify another to reflect that
non-directory patterns are caught earlier.
Signed-off-by: William Sprent <williams@unity3d.com>
Acked-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As well as removing the explicit shell setting d8b21a0fe2 (CI: don't
explicitly pick "bash" shell outside of Windows, fix regression,
2022-12-07) also reverted the name of the print test failures step
introduced by 5aeb145780 (ci(github): bring back the 'print test
failures' step, 2022-06-08). This is unfortunate as 5aeb145780 added a
message to direct contributors to the "print test failures" step when a
test fails and that step is no-longer known by that name on the
non-windows ci jobs.
In principle we could update the message to print the correct name for
the step but then we'd have to deal with having two different names for
the same step on different jobs. It is simpler for the implementation
and contributors to use the same name for this step on all jobs.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix the sequence to fsync $GIT_DIR/packed-refs file that forgot to
flush its output to the disk..
* ps/fsync-refs-fix:
refs: fix corruption by not correctly syncing packed-refs to disk
"git format-patch" learned to honor format.mboxrd even when sending
patches to the standard output stream,
* ew/format-patch-mboxrd:
format-patch: support format.mboxrd with --stdout
Bundle URIs part 4.
* ds/bundle-uri-4:
clone: unbundle the advertised bundles
bundle-uri: download bundles from an advertised list
bundle-uri: allow relative URLs in bundle lists
strbuf: introduce strbuf_strip_file_from_path()
bundle-uri: serve bundle.* keys from config
bundle-uri client: add helper for testing server
transport: rename got_remote_heads
bundle-uri client: add boolean transfer.bundleURI setting
clone: request the 'bundle-uri' command when available
t: create test harness for 'bundle-uri' command
protocol v2: add server-side "bundle-uri" skeleton
When given a pattern that matches an empty string at the end of a
line, the code to parse the "git diff" line-ranges fell into an
infinite loop, which has been corrected.
* lk/line-range-parsing-fix:
line-range: fix infinite loop bug with '$' regex
Just like "git var GIT_EDITOR" abstracts the complex logic to
choose which editor gets used behind it, "git var" now give support
to GIT_SEQUENCE_EDITOR.
* sa/git-var-sequence-editor:
var: add GIT_SEQUENCE_EDITOR variable
"git pull -v --recurse-submodules" attempted to pass "-v" down to
underlying "git submodule update", which did not understand the
request and barfed, which has been corrected.
* ss/pull-v-recurse-fix:
submodule: accept -v for the update command
Improve the usage we emit on e.g. "git bundle create" to note why
we're showing the usage, it's because the "<file>" argument is
missing.
We know that'll be the case for all parse_options_cmd_bundle() users,
as they're passing the "char **bundle_file" parameter, which as the
context shows we're expected to populate.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As noted in 891cb09db6 (bundle: don't segfault on "git bundle
<subcmd>", 2022-12-20) the "newargc" in this function is redundant to
using our own "argc". Let's refactor the function to avoid needlessly
introducing another variable.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the description of --force to use '<start-point>' rather than
'<startpoint>' to match the spelling used everywhere else in the
git-branch documentation.
Signed-off-by: Kyle Meyer <kyle@kyleam.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use the SHA1DC implementation on macOS, just like other platforms,
by default.
* ab/darwin-default-to-sha1dc:
Makefile: use sha1collisiondetection by default on OSX and Darwin
