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The "gc" task has a similar locking race as the one that we have fixed
for the "pack-refs" and "reflog-expire" tasks in preceding commits. Fix
this by splitting up the logic of the "gc" task:
- We execute `gc_before_repack()` in the foreground, which contains
the logic that git-gc(1) itself would execute in the foreground, as
well.
- We spawn git-gc(1) after detaching, but with a new hidden flag that
suppresses calling `gc_before_repack()`.
Like this we have roughly the same logic as git-gc(1) itself and know to
repack refs and reflogs before detaching, thus fixing the race.
Note that `gc_before_repack()` is renamed to `gc_foreground_tasks()` to
better reflect what this function does.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The `gc_before_repack()` should only ever run once in git-gc(1), but we
may end up calling it twice when the "--detach" flag is passed. The
duplicated call is avoided though via a static flag in this function.
This pattern is somewhat unintuitive though. Refactor it to drop the
static flag and instead guard the second call of `gc_before_repack()`
via `opts.detach`.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Sometimes code wants to die in a situation where it already has written
an error message. To use the same error code as `die()` we have to use
`exit(128)`, which is easy to get wrong and leaves magic numbers all
over our codebase.
Teach `die_message_builtin()` to not print any error when passed a
`NULL` pointer as error string. Like this, such users can now call
`die(NULL)` to achieve the same result without any hardcoded error
codes.
Adapt a couple of builtins to use this new pattern to demonstrate that
there is a need for such a helper.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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As explained in the preceding commit, git-gc(1) knows to detach only
after it has already packed references and expired reflogs. This is done
to avoid racing around their respective lockfiles.
Adapt git-maintenance(1) accordingly and run the "pack-refs" and
"reflog-expire" tasks in the foreground. Note that the "gc" task has the
same issue, but the fix is a bit more involved there and will thus be
done in a subsequent commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Both git-gc(1) and git-maintenance(1) have logic to daemonize so that
the maintenance tasks are performed in the background. git-gc(1) has
some special logic though to not perform _all_ housekeeping tasks in the
background: both references and reflogs are still handled synchronously
in the foreground.
This split exists because otherwise it may easily happen that git-gc(1)
keeps the "packed-refs" file locked for an extended amount of time,
where the next Git command that wants to modify any reference could now
fail. This was especially important in the past, where git-gc(1) was
still executed directly as part of our automatic maintenance: git-gc(1)
was invoked via `git gc --auto --detach`, so we knew to handle most of
the maintenance tasks in the background while doing those parts that may
cause locking issues in the foreground.
We have since moved to git-maintenance(1), which is a more flexible
replacement for git-gc(1). By default this command runs git-gc(1), only,
but it can be configured to run different tasks, as well. This command
does not know about the split between maintenance tasks that should run
before and after detach though, and this has led to several bug reports
about spurious locking errors for the "packed-refs" file.
Prepare for a fix by introducing this split for maintenance tasks. Note
that this commit does not yet change any of the tasks, so there should
not (yet) be a change in behaviour.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The typedefs for `maintenance_task_fn` and `maintenance_auto_fn` are
somewhat confusingly not true function pointers. As such, any user of
those typedefs needs to manually add the pointer to make use of them.
Fix this by making these true function pointers.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Extract the function to run maintenance tasks. This function will be
reused in a subsequent commit where we introduce a split between
maintenance tasks that run before and after daemonizing the process.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When configuring maintenance tasks run by git-maintenance(1) we do so by
modifying the global array of tasks directly. This is already quite bad
on its own, as global state makes for logic that is hard to follow.
Even more importantly though we use multiple different fields to track
whether or not a task should be run:
- "enabled" tracks the "maintenance.*.enabled" config key. This field
disables execution of a task, unless the user has explicitly asked
for the task.
- "selected_order" tracks the order in which jobs have been asked for
by the user via the "--task=" command line option. It overrides
everything else, but only has an effect if at least one job has been
selected.
- "schedule" tracks the schedule priority for a job, that is how often
it should run. This field only plays a role when the user has passed
the "--schedule=" command line option.
All of this makes it non-trivial to figure out which job really should
be running right now. The logic to configure these fields and the logic
that interprets them is distributed across multiple functions, making it
even harder to follow it.
Refactor the logic so that we stop modifying global state. Instead, we
now compute which jobs should be run in `initialize_task_config()`,
represented as an array of jobs to run that is stored in the options
structure. Like this, all logic becomes self-contained and any users of
this array only need to iterate through the tasks and execute them one
by one.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The "--task=" option explicitly allows the user to say which maintenance
tasks should be run, whereas "--schedule=" only respects the maintenance
strategy configured for a specific repository. As such, it is not
sensible to accept both options at the same time.
Mark them as incompatible with one another. While at it, also convert
the existing logic that marks "--auto" and "--schedule=" as incompatible
to use `die_for_incompatible_opt2()`.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Users of git-maintenance(1) can explicitly ask it to run specific tasks
by passing the `--task=` command line option. This option can be passed
multiple times, which causes us to execute tasks in the same order as
the tasks have been provided by the user.
The order in which tasks are run is computed in `task_option_parse()`:
every time we parse such a command line argument, we modify the global
array of tasks by seting the selected index for that specific task.
This has two downsides:
- We modify global state, which makes it hard to follow the logic.
- The configuration of tasks is split across multiple different
functions, so it is not easy to figure out the different factors
that play a role in selecting tasks.
Refactor the logic so that `task_option_parse()` does not modify global
state anymore. Instead, this function now only collects the list of
configured tasks. The logic to configure ordering of the respective
tasks is then deferred to `initialize_task_config()`.
This refactoring solves the second problem, that the configuration of
tasks is spread across multiple different locations. The first problem,
that we modify global state, will be fixed in a subsequent commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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We have two different variables that track the quietness for git-gc(1):
- The local variable `quiet`, which we wire up.
- The `quiet` field of `struct maintenance_run_opts`.
This leads to confusion which of these variables should be used and what
the respective effect is.
Simplify this logic by dropping the local variable in favor of the
options field.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Convert the array of maintenance tasks to use designated field
initializers. This makes it easier to add more fields to the struct
without having to modify all tasks.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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OpenBSD / NetBSD use HW_PHYSMEM64 to detect the amount of physical
memory in a system. HW_PHYSMEM will not provide the correct amount
on a system with >=4GB of memory.
Signed-off-by: Brad Smith <brad@comstyle.com>
Reviewed-by: Collin Funk <collin.funk1@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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As the design of signature handling is still being discussed, it is
likely that the data stream produced by the code in Git 2.50 would
have to be changed in such a way that is not backward compatible.
Mark the feature as experimental and discourge its use for now.
Also flip the default on the generation side to "strip"; users of
existing versions would not have passed --signed-commits=strip and
will be broken by this change if the default is made to abort, and
will be encouraged by the error message to produce data stream with
future breakage guarantees by passing --signed-commits option.
As we tone down the default behaviour, we no longer need the
FAST_EXPORT_SIGNED_COMMITS_NOABORT environment variable, which was
not discoverable enough.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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"git receive-pack" optionally learns not to care about connectivity
check, which can be useful when the repository arranges to ensure
connectivity by some other means.
* jt/receive-pack-skip-connectivity-check:
builtin/receive-pack: add option to skip connectivity check
t5410: test receive-pack connectivity check
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Assorted fixes for issues found with CodeQL.
* js/misc-fixes:
sequencer: stop pretending that an assignment is a condition
bundle-uri: avoid using undefined output of `sscanf()`
commit-graph: avoid using stale stack addresses
trace2: avoid "futile conditional"
Avoid redundant conditions
fetch: avoid unnecessary work when there is no current branch
has_dir_name(): make code more obvious
upload-pack: rename `enum` to reflect the operation
commit-graph: avoid malloc'ing a local variable
fetch: carefully clear local variable's address after use
commit: simplify code
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"git apply" and "git add -i/-p" code paths no longer unnecessarily
expand sparse-index while working.
* ds/sparse-apply-add-p:
p2000: add performance test for patch-mode commands
reset: integrate sparse index with --patch
git add: make -p/-i aware of sparse index
apply: integrate with the sparse index
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"git merge-tree" learned an option to see if it resolves cleanly
without actually creating a result.
* en/merge-tree-check:
merge-tree: add a new --quiet flag
merge-ort: add a new mergeability_only option
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Support to create a loose object file with unknown object type has
been dropped.
* jk/no-funny-object-types:
object-file: drop support for writing objects with unknown types
hash-object: handle --literally with OPT_NEGBIT
hash-object: merge HASH_* and INDEX_* flags
hash-object: stop allowing unknown types
t: add lib-loose.sh
t/helper: add zlib test-tool
oid_object_info(): drop type_name strbuf
fsck: stop using object_info->type_name strbuf
oid_object_info_convert(): stop using string for object type
cat-file: use type enum instead of buffer for -t option
object-file: drop OBJECT_INFO_ALLOW_UNKNOWN_TYPE flag
cat-file: make --allow-unknown-type a noop
object-file.h: fix typo in variable declaration
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The dependency on the_repository variable has been reduced from the
code paths in "git replay".
* en/replay-wo-the-repository:
replay: replace the_repository with repo parameter passed to cmd_replay ()
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The --no-index option of git-diff enables using the diff machinery from
git while operating outside of a repository. This mode of git diff is
able to compare directories and produce a diff of their contents.
When operating git diff in a repository, git has the notion of
"pathspecs" which can specify which files to compare. In particular,
when using git to diff two trees, you might invoke:
$ git diff-tree -r <treeish1> <treeish2>.
where the treeish could point to a subdirectory of the repository.
When invoked this way, users can limit the selected paths of the tree by
using a pathspec. Either by providing some list of paths to accept, or
by removing paths via a negative refspec.
The git diff --no-index mode does not support pathspecs, and cannot
limit the diff output in this way. Other diff programs such as GNU
difftools have options for excluding paths based on a pattern match.
However, using git diff as a diff replacement has several advantages
over many popular diff tools, including coloring moved lines, rename
detections, and similar.
Teach git diff --no-index how to handle pathspecs to limit the
comparisons. This will only be supported if both provided paths are
directories.
For comparisons where one path isn't a directory, the --no-index mode
already has some DWIM shortcuts implemented in the fixup_paths()
function.
Modify the fixup_paths function to return 1 if both paths are
directories. If this is the case, interpret any extra arguments to git
diff as pathspecs via parse_pathspec.
Use parse_pathspec to load the remaining arguments (if any) to git diff
--no-index as pathspec items. Disable PATHSPEC_ATTR support since we do
not have a repository to do attribute lookup. Disable PATHSPEC_FROMTOP
since we do not have a repository root. All pathspecs are treated as
rooted at the provided comparison paths.
After loading the pathspec data, calculate skip offsets for skipping
past the root portion of the paths. This is required to ensure that
pathspecs start matching from the provided path, rather than matching
from the absolute path. We could instead pass the paths as prefix values
to parse_pathspec. This is slightly problematic because the paths come
from the command line and don't necessarily have the proper trailing
slash. Additionally, that would require parsing pathspecs multiple
times.
Pass the pathspec object and the skip offsets into queue_diff, which
in-turn must pass them along to read_directory_contents.
Modify read_directory_contents to check against the pathspecs when
scanning the directory. Use the skip offset to skip past the initial
root of the path, and only match against portions that are below the
intended directory structure being compared.
The search algorithm for finding paths is recursive with read_dir. To
make pathspec matching work properly, we must set both
DO_MATCH_DIRECTORY and DO_MATCH_LEADING_PATHSPEC.
Without DO_MATCH_DIRECTORY, paths like "a/b/c/d" will not match against
pathspecs like "a/b/c". This is usually achieved by setting the is_dir
parameter of match_pathspec.
Without DO_MATCH_LEADING_PATHSPEC, paths like "a/b/c" would not match
against pathspecs like "a/b/c/d". This is crucial because we recursively
iterate down the directories. We could simply avoid checking pathspecs
at subdirectories, but this would force recursion down directories
which would simply be skipped.
If we always passed DO_MATCH_LEADING_PATHSPEC, then we will
incorrectly match in certain cases such as matching 'a/c' against
':(glob)**/d'. The match logic will see that a matches the leading part
of the **/ and accept this even tho c doesn't match.
To avoid this, use the match_leading_pathspec() variant recently
introduced. This sets both flags when is_dir is set, but leaves them
both cleared when is_dir is 0.
Add test cases and documentation covering the new functionality. Note
for the documentation I opted not to move the placement of '--' which is
sometimes used to disambiguate arguments. The diff --no-index mode
requires exactly 2 arguments determining what to compare. Any additional
arguments are interpreted as pathspecs and must come afterwards. Use of
'--' would not actually disambiguate anything, since there will never be
ambiguity over which arguments represent paths or pathspecs.
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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During git-receive-pack(1), connectivity of the object graph is
validated to ensure that the received packfile does not leave the
repository in a broken state. This is done via git-rev-list(1) and
walking the objects, which can be expensive for large repositories.
Generally, this check is critical to avoid an incomplete received
packfile from corrupting a repository. Server operators may have
additional knowledge though around exactly how Git is being used on the
server-side which can be used to facilitate more efficient connectivity
computation of incoming objects.
For example, if it can be ensured that all objects in a repository are
connected and do not depend on any missing objects, the connectivity of
newly written objects can be checked by walking the object graph
containing only the new objects from the updated tips and identifying
the missing objects which represent the boundary between the new objects
and the repository. These boundary objects can be checked in the
canonical repository to ensure the new objects connect as expected and
thus avoid walking the rest of the object graph.
Git itself cannot make the guarantees required for such an optimization
as it is possible for a repository to contain an unreachable object that
references a missing object without the repository being considered
corrupt.
Introduce the --skip-connectivity-check option for git-receive-pack(1)
which bypasses this connectivity check to give more control to the
server-side. Note that without proper server-side validation of newly
received objects handled outside of Git, usage of this option risks
corrupting a repository.
Signed-off-by: Justin Tobler <jltobler@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Code cleanup.
* jk/oidmap-cleanup:
raw_object_store: drop extra pointer to replace_map
oidmap: add size function
oidmap: rename oidmap_free() to oidmap_clear()
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Leakfix.
* ly/am-split-stgit-leakfix:
builtin/am: fix memory leak in `split_mail_stgit_series`
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The reference updates performed as a part of 'git-receive-pack(1)', take
place one at a time. For each reference update, a new transaction is
created and committed. This is necessary to ensure we can allow
individual updates to fail without failing the entire command. The
command also supports an 'atomic' mode, which uses a single transaction
to update all of the references. But this mode has an all-or-nothing
approach, where if a single update fails, all updates would fail.
In 23fc8e4f61 (refs: implement batch reference update support,
2025-04-08), we introduced a new mechanism to batch reference updates.
Under the hood, this uses a single transaction to perform a batch of
reference updates, while allowing only individual updates to fail.
Utilize this newly introduced batch update mechanism in
'git-receive-pack(1)'. This provides a significant bump in performance,
especially when dealing with repositories with large number of
references.
With the reftable backend there is a 18x performance improvement, when
performing receive-pack with 10000 refs:
Benchmark 1: receive: many refs (refformat = reftable, refcount = 10000, revision = master)
Time (mean ± σ): 4.276 s ± 0.078 s [User: 0.796 s, System: 3.318 s]
Range (min … max): 4.185 s … 4.430 s 10 runs
Benchmark 2: receive: many refs (refformat = reftable, refcount = 10000, revision = HEAD)
Time (mean ± σ): 235.4 ms ± 6.9 ms [User: 75.4 ms, System: 157.3 ms]
Range (min … max): 228.5 ms … 254.2 ms 11 runs
Summary
receive: many refs (refformat = reftable, refcount = 10000, revision = HEAD) ran
18.16 ± 0.63 times faster than receive: many refs (refformat = reftable, refcount = 10000, revision = master)
In similar conditions, the files backend sees a 1.21x performance
improvement:
Benchmark 1: receive: many refs (refformat = files, refcount = 10000, revision = master)
Time (mean ± σ): 1.121 s ± 0.021 s [User: 0.128 s, System: 0.975 s]
Range (min … max): 1.097 s … 1.156 s 10 runs
Benchmark 2: receive: many refs (refformat = files, refcount = 10000, revision = HEAD)
Time (mean ± σ): 927.9 ms ± 22.6 ms [User: 99.0 ms, System: 815.2 ms]
Range (min … max): 903.1 ms … 978.0 ms 10 runs
Summary
receive: many refs (refformat = files, refcount = 10000, revision = HEAD) ran
1.21 ± 0.04 times faster than receive: many refs (refformat = files, refcount = 10000, revision = master)
As using batched updates requires the error handling to be moved to the
end of the flow, create and use a 'struct strset' to track the failed
refs and attribute the correct errors to them.
This change also uncovers an issue when a client provides multiple
updates to the same reference. For example:
$ git send-pack remote.git A:foo B:foo
Enumerating objects: 3, done.
Counting objects: 100% (3/3), done.
Delta compression using up to 20 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 226 bytes | 226.00 KiB/s, done.
Total 3 (delta 1), reused 0 (delta 0), pack-reused 0 (from 0)
remote: error: cannot lock ref 'refs/heads/foo': reference already exists
To remote.git
! [remote rejected] A -> foo (failed to update ref)
! [remote failure] B -> foo (remote failed to report status)
As you can see, the remote runs into an error because it cannot lock the
target reference for the second update. Furthermore, the remote complains
that the first update has been rejected whereas the second update didn't
receive any status update because we failed to lock it. Reading this status
message alone a user would probably expect that `foo` has not been updated
at all. But that's not the case: while we claim that the ref wasn't updated,
it surprisingly points to `A` now.
One could argue that this is merely an error in how we report the result of
this push. But ultimately, the user's request itself is already broken and
doesn't make any sense in the first place and cannot ever lead to a sensible
outcome that honors the full request.
The conversion to batched transactions fixes the issue because we now try to
queue both updates in the same transaction. As such, the transaction itself
will notice this conflict and refuse the update altogether before we commit
any of the values.
Note that this requires changes to a couple of tests in t5408 that happened
to exercise this behaviour. Given that the generated output is misleading
and given that the user request cannot ever be fully honored this really
feels more like a bug than properly designed behaviour. As such, changing
the behaviour feels like the right thing to do.
Since now reference updates are batched, the 'reference-transaction'
hook will be invoked with all updates together. Currently git will 'die'
when the hook returns with a non-zero exit status in the 'prepared'
stage. For 'git-receive-pack(1)', this allowed users to reject an
individual reference update, git would have applied previous updates but
immediately abort further execution. This is definitely an incorrect
usage of this hook, since the right place to do this would be the
'update' hook. This patch retains the latter behavior, but
'reference-transaction' hook now changes to a all-or-nothing behavior
when a non-zero exit status is returned in the 'prepared' stage, since
batch updates use a transaction under the hood. This explains the change
in 't1416'.
Helped-by: Jeff King <peff@peff.net>
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The reference updates performed as a part of 'git-fetch(1)', take place
one at a time. For each reference update, a new transaction is created
and committed. This is necessary to ensure we can allow individual
updates to fail without failing the entire command. The command also
supports an '--atomic' mode, which uses a single transaction to update
all of the references. But this mode has an all-or-nothing approach,
where if a single update fails, all updates would fail.
In 23fc8e4f61 (refs: implement batch reference update support,
2025-04-08), we introduced a new mechanism to batch reference updates.
Under the hood, this uses a single transaction to perform a batch of
reference updates, while allowing only individual updates to fail.
Utilize this newly introduced batch update mechanism in 'git-fetch(1)'.
This provides a significant bump in performance, especially when dealing
with repositories with large number of references.
Adding support for batched updates is simply modifying the flow to also
create a batch update transaction in the non-atomic flow.
With the reftable backend there is a 22x performance improvement, when
performing 'git-fetch(1)' with 10000 refs:
Benchmark 1: fetch: many refs (refformat = reftable, refcount = 10000, revision = master)
Time (mean ± σ): 3.403 s ± 0.775 s [User: 1.875 s, System: 1.417 s]
Range (min … max): 2.454 s … 4.529 s 10 runs
Benchmark 2: fetch: many refs (refformat = reftable, refcount = 10000, revision = HEAD)
Time (mean ± σ): 154.3 ms ± 17.6 ms [User: 102.5 ms, System: 56.1 ms]
Range (min … max): 145.2 ms … 220.5 ms 18 runs
Summary
fetch: many refs (refformat = reftable, refcount = 10000, revision = HEAD) ran
22.06 ± 5.62 times faster than fetch: many refs (refformat = reftable, refcount = 10000, revision = master)
In similar conditions, the files backend sees a 1.25x performance
improvement:
Benchmark 1: fetch: many refs (refformat = files, refcount = 10000, revision = master)
Time (mean ± σ): 605.5 ms ± 9.4 ms [User: 117.8 ms, System: 483.3 ms]
Range (min … max): 595.6 ms … 621.5 ms 10 runs
Benchmark 2: fetch: many refs (refformat = files, refcount = 10000, revision = HEAD)
Time (mean ± σ): 485.8 ms ± 4.3 ms [User: 91.1 ms, System: 396.7 ms]
Range (min … max): 477.6 ms … 494.3 ms 10 runs
Summary
fetch: many refs (refformat = files, refcount = 10000, revision = HEAD) ran
1.25 ± 0.02 times faster than fetch: many refs (refformat = files, refcount = 10000, revision = master)
With this we'll either be using a regular transaction or a batch update
transaction. This helps cleanup some code which is no longer needed as
we'll now always have some type of 'ref_transaction' object being
propagated.
One big change is that earlier, each individual update would propagate a
failure. Whereas now, the `ref_transaction_for_each_rejected_update`
function is called at the end of the flow to capture the exit status for
'git-fetch(1)' and also to print F/D conflict errors. This does change
the order of the errors being printed, but the behavior stays the same.
Since transaction errors are now explicitly defined as part of
76e760b999 (refs: introduce enum-based transaction error types,
2025-04-08), utilize them and get rid of custom errors defined within
'builtin/fetch.c'.
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The commit 76e760b999 (refs: introduce enum-based transaction error
types, 2025-04-08) introduced enum-based transaction error types. The
refs transaction logic was also modified to propagate these errors. For
clients of the ref transaction system, it would be beneficial to provide
human readable messages for these errors.
There is already an existing mapping in 'builtin/update-ref.c', move it
to 'refs.c' as `ref_transaction_error_msg()` and use the same within the
'builtin/update-ref.c'.
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Git Forges may be interested in whether two branches can be merged while
not being interested in what the resulting merge tree is nor which files
conflicted. For such cases, add a new --quiet flag which
will make use of the new mergeability_only flag added to merge-ort in
the previous commit. This option allows the merge machinery to, in the
outer layer of the merge:
* exit early when a conflict is detected
* avoid writing (most) merged blobs/trees to the object store
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
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There does not appear to be anything particularly incompatible about the
--shallow and --path-walk options of 'git pack-objects'. If shallow
commits are to be handled differently, then it is by the revision walk
that defines the commit set and which are interesting or uninteresting.
However, before the previous change, a trivial removal of the warning
would cause a failure in t5500-fetch-pack.sh when
GIT_TEST_PACK_PATH_WALK is enabled. The shallow fetch would provide more
objects than we desired, due to some incorrect behavior of the path-walk
API, especially around walking uninteresting objects.
The recently-added tests in t5538-push-shallow.sh help to confirm this
behavior is working with the --path-walk option if
GIT_TEST_PACK_PATH_WALK is enabled. These tests passed previously due to
the --path-walk feature being disabled in the presence of a shallow
clone.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
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Adapting the implementation of ll_find_deltas(), create a threaded
version of the --path-walk compression step in 'git pack-objects'.
This involves adding a 'regions' member to the thread_params struct,
allowing each thread to own a section of paths. We can simplify the way
jobs are split because there is no value in extending the batch based on
name-hash the way sections of the object entry array are attempted to be
grouped. We re-use the 'list_size' and 'remaining' items for the purpose
of borrowing work in progress from other "victim" threads when a thread
has finished its batch of work more quickly.
Using the Git repository as a test repo, the p5313 performance test
shows that the resulting size of the repo is the same, but the threaded
implementation gives gains of varying degrees depending on the number of
objects being packed. (This was tested on a 16-core machine.)
Test HEAD~1 HEAD
---------------------------------------------------
5313.20: big pack 2.38 1.99 -16.4%
5313.21: big pack size 16.1M 16.0M -0.2%
5313.24: repack 107.32 45.41 -57.7%
5313.25: repack size 213.3M 213.2M -0.0%
(Test output is formatted to better fit in message.)
This ~60% reduction in 'git repack --path-walk' time is typical across
all repos I used for testing. What is interesting is to compare when the
overall time improves enough to outperform the --name-hash-version=1
case. These time improvements correlate with repositories with data
shapes that significantly improve their data size as well. The
--path-walk feature frequently takes longer than --name-hash-version=2,
trading some extra computation for some additional compression. The
natural place where this additional computation comes from is the two
compression passes that --path-walk takes, though the first pass is
naturally faster due to the path boundaries avoiding a number of delta
compression attempts.
For example, the microsoft/fluentui repo has significant size reduction
from --name-hash-version=1 to --name-hash-version=2 followed by further
improvements with --path-walk. The threaded computation makes
--path-walk more competitive in time compared to --name-hash-version=2,
though still ~31% more expensive in that metric.
Repack Method Pack Size Time
------------------------------------------
Hash v1 439.4M 87.24s
Hash v2 161.7M 21.51s
Path Walk (Before) 142.5M 81.29s
Path Walk (After) 142.5M 28.16s
Similar results hold for the Git repository:
Repack Method Pack Size Time
------------------------------------------
Hash v1 248.8M 30.44s
Hash v2 249.0M 30.15s
Path Walk (Before) 213.2M 142.50s
Path Walk (After) 213.3M 45.41s
...as well as the nodejs/node repository:
Repack Method Pack Size Time
------------------------------------------
Hash v1 739.9M 71.18s
Hash v2 764.6M 67.82s
Path Walk (Before) 698.1M 208.10s
Path Walk (After) 698.0M 75.10s
Finally, the Linux kernel repository is a good test for this repacking
time change, even though the space savings is more subtle:
Repack Method Pack Size Time
------------------------------------------
Hash v1 2.5G 554.41s
Hash v2 2.5G 549.62s
Path Walk (before) 2.2G 1562.36s
Path Walk (before) 2.2G 559.00s
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
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Previously, the --path-walk option to 'git pack-objects' would compute
deltas inline with the path-walk logic. This would make the progress
indicator look like it is taking a long time to enumerate objects, and
then very quickly computed deltas.
Instead of computing deltas on each region of objects organized by tree,
store a list of regions corresponding to these groups. These can later
be pulled from the list for delta compression before doing the "global"
delta search.
This presents a new progress indicator that can be used in tests to
verify that this stage is happening.
The current implementation is not integrated with threads, but we are
setting it up to arrive in the next change.
Since we do not attempt to sort objects by size until after exploring
all trees, we can remove the previous change to t5530 due to a different
error message appearing first.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
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Users may want to enable the --path-walk option for 'git pack-objects' by
default, especially underneath commands like 'git push' or 'git repack'.
This should be limited to client repositories, since the --path-walk option
disables bitmap walks, so would be bad to include in Git servers when
serving fetches and clones. There is potential that it may be helpful to
consider when repacking the repository, to take advantage of improved deltas
across historical versions of the same files.
Much like how "pack.useSparse" was introduced and included in
"feature.experimental" before being enabled by default, use the repository
settings infrastructure to make the new "pack.usePathWalk" config enabled by
"feature.experimental" and "feature.manyFiles".
In order to test that this config works, add a new trace2 region around
the path walk code that can be checked by a 'git push' command.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
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Since 'git pack-objects' supports a --path-walk option, allow passing it
through in 'git repack'. This presents interesting testing opportunities for
comparing the different repacking strategies against each other.
Add the --path-walk option to the performance tests in p5313.
For the microsoft/fluentui repo [1] checked out at a specific commit [2],
the --path-walk tests in p5313 look like this:
Test this tree
-------------------------------------------------------------------------
5313.18: thin pack with --path-walk 0.08(0.06+0.02)
5313.19: thin pack size with --path-walk 18.4K
5313.20: big pack with --path-walk 2.10(7.80+0.26)
5313.21: big pack size with --path-walk 19.8M
5313.22: shallow fetch pack with --path-walk 1.62(3.38+0.17)
5313.23: shallow pack size with --path-walk 33.6M
5313.24: repack with --path-walk 81.29(96.08+0.71)
5313.25: repack size with --path-walk 142.5M
[1] https://github.com/microsoft/fluentui
[2] e70848ebac1cd720875bccaa3026f4a9ed700e08
Along with the earlier tests in p5313, I'll instead reformat the
comparison as follows:
Repack Method Pack Size Time
---------------------------------------
Hash v1 439.4M 87.24s
Hash v2 161.7M 21.51s
Path Walk 142.5M 81.29s
There are a few things to notice here:
1. The benefits of --name-hash-version=2 over --name-hash-version=1 are
significant, but --path-walk still compresses better than that
option.
2. The --path-walk command is still using --name-hash-version=1 for the
second pass of delta computation, using the increased name hash
collisions as a potential method for opportunistic compression on
top of the path-focused compression.
3. The --path-walk algorithm is currently sequential and does not use
multiple threads for delta compression. Threading will be
implemented in a future change so the computation time will improve
to better compete in this metric.
There are small benefits in size for my copy of the Git repository:
Repack Method Pack Size Time
---------------------------------------
Hash v1 248.8M 30.44s
Hash v2 249.0M 30.15s
Path Walk 213.2M 142.50s
As well as in the nodejs/node repository [3]:
Repack Method Pack Size Time
---------------------------------------
Hash v1 739.9M 71.18s
Hash v2 764.6M 67.82s
Path Walk 698.1M 208.10s
[3] https://github.com/nodejs/node
This benefit also repeats in my copy of the Linux kernel repository:
Repack Method Pack Size Time
---------------------------------------
Hash v1 2.5G 554.41s
Hash v2 2.5G 549.62s
Path Walk 2.2G 1562.36s
It is important to see that even when the repository shape does not have
many name-hash collisions, there is a slight space boost to be found
using this method.
As this repacking strategy was released in Git for Windows 2.47.0, some
users have reported cases where the --path-walk compression is slightly
worse than the --name-hash-version=2 option. In those cases, it may be
beneficial to combine the two options. However, there has not been a
released version of Git that has both options and I don't have access to
these repos for testing.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
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There are many tests that validate whether 'git pack-objects' works as
expected. Instead of duplicating these tests, add a new test environment
variable, GIT_TEST_PACK_PATH_WALK, that implies --path-walk by default
when specified.
This was useful in testing the implementation of the --path-walk
implementation, helping to find tests that are overly specific to the
default object walk. These include:
- t0411-clone-from-partial.sh : One test fetches from a repo that does
not have the boundary objects. This causes the path-based walk to
fail. Disable the variable for this test.
- t5306-pack-nobase.sh : Similar to t0411, one test fetches from a repo
without a boundary object.
- t5310-pack-bitmaps.sh : One test compares the case when packing with
bitmaps to the case when packing without them. Since we disable the
test variable when writing bitmaps, this causes a difference in the
object list (the --path-walk option adds an extra object). Specify
--no-path-walk in both processes for the comparison. Another test
checks for a specific delta base, but when computing dynamically
without using bitmaps, the base object it too small to be considered
in the delta calculations so no base is used.
- t5316-pack-delta-depth.sh : This script cares about certain delta
choices and their chain lengths. The --path-walk option changes how
these chains are selected, and thus changes the results of this test.
- t5322-pack-objects-sparse.sh : This demonstrates the effectiveness of
the --sparse option and how it combines with --path-walk.
- t5332-multi-pack-reuse.sh : This test verifies that the preferred
pack is used for delta reuse when possible. The --path-walk option is
not currently aware of the preferred pack at all, so finds a
different delta base.
- t7406-submodule-update.sh : When using the variable, the --depth
option collides with the --path-walk feature, resulting in a warning
message. Disable the variable so this warning does not appear.
I want to call out one specific test change that is only temporary:
- t5530-upload-pack-error.sh : One test cares specifically about an
"unable to read" error message. Since the current implementation
performs delta calculations within the path-walk API callback, a
different "unable to get size" error message appears. When this
is changed in a future refactoring, this test change can be reverted.
Similar to GIT_TEST_NAME_HASH_VERSION, we do not add this option to the
linux-TEST-vars CI build as that's already an overloaded build.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
The t0450 test script verifies that builtin usage matches the synopsis
in the documentation. Adjust the builtin to match and then remove 'git
pack-objects' from the exception list.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
In order to more easily compute delta bases among objects that appear at
the exact same path, add a --path-walk option to 'git pack-objects'.
This option will use the path-walk API instead of the object walk given
by the revision machinery. Since objects will be provided in batches
representing a common path, those objects can be tested for delta bases
immediately instead of waiting for a sort of the full object list by
name-hash. This has multiple benefits, including avoiding collisions by
name-hash.
The objects marked as UNINTERESTING are included in these batches, so we
are guaranteeing some locality to find good delta bases.
After the individual passes are done on a per-path basis, the default
name-hash is used to find other opportunistic delta bases that did not
match exactly by the full path name.
The current implementation performs delta calculations while walking
objects, which is not ideal for a few reasons. First, this will cause
the "Enumerating objects" phase to be much longer than usual. Second, it
does not take advantage of threading during the path-scoped delta
calculations. Even with this lack of threading, the path-walk option is
sometimes faster than the usual approach. Future changes will refactor
this code to allow for threading, but that complexity is deferred until
later to keep this patch as simple as possible.
This new walk is incompatible with some features and is ignored by
others:
* Object filters are not currently integrated with the path-walk API,
such as sparse-checkout or tree depth. A blobless packfile could be
integrated easily, but that is deferred for later.
* Server-focused features such as delta islands, shallow packs, and
using a bitmap index are incompatible with the path-walk API.
* The path walk API is only compatible with the --revs option, not
taking object lists or pack lists over stdin. These alternative ways
to specify the objects currently ignores the --path-walk option
without even a warning.
Future changes will create performance tests that demonstrate the power
of this approach.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
This will be helpful in a future change, which will reuse this logic.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
Similar to the previous change for 'git add -p', the reset builtin
checked for integration with the sparse index after possibly redirecting
its logic toward the interactive logic. This means that the builtin
would expand the sparse index to a full one upon read.
Move this check earlier within cmd_reset() to improve performance here.
Add tests to guarantee that we are not universally expanding the index.
Add behavior tests to check that we are doing the same operations as a
full index.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
It is slow to expand a sparse index in-memory due to parsing of trees.
We aim to minimize that performance cost when possible. 'git add -p'
uses 'git apply' child processes to modify the index, but still there
are some expansions that occur.
It turns out that control flows out of cmd_add() in the interactive
cases before the lines that confirm that the builtin is integrated with
the sparse index.
Moving that integration point earlier in cmd_add() allows 'git add -i'
and 'git add -p' to operate without expanding a sparse index to a full
one.
Add test cases that confirm that these interactive add options work with
the sparse index.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
The sparse index allows storing directory entries in the index, marked
with the skip-wortkree bit and pointing to a tree object. This may be an
unexpected data shape for some implementation areas, so we are rolling
it out incrementally on a builtin-per-builtin basis.
This change enables the sparse index for 'git apply'. The main
motivation for this change is that 'git apply' is used as a child
process of 'git add -p' and expanding the sparse index for each of those
child processes can lead to significant performance issues.
The good news is that the actual index manipulation code used by 'git
apply' is already integrated with the sparse index, so the only product
change is to mark the builtin as allowing the sparse index so it isn't
inflated on read.
The more involved part of this change is around adding tests that verify
how 'git apply' behaves in a sparse-checkout environment and whether or
not the index expands in certain operations.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
Since we recently removed the hash_literally() function, the hash-object
--literally option has been simplified to just removing the
INDEX_FORMAT_CHECK flag. Rather than pass it around as a separate bool,
we can just have the option parser remove the bit from the set of flags
directly. This simplifies the helper functions.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
The hash-object command has its own custom flag bits that it sets based
on command-line options. But since we dropped hash_literally() in the
previous commit, the only thing we do with those flag bits is convert
them directly into "index_flags" to pass to index_fd().
This extra layer of indirection makes the code harder to read and reason
about. Let's just use the INDEX_* flags directly.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
When passed the "--literally" option, hash-object will allow any
arbitrary string for its "-t" type option. Such objects are only useful
for testing or debugging, as they cannot be used in the normal way
(e.g., you cannot fetch their contents!).
Let's drop this feature, which will eventually let us simplify the
object-writing code. This is technically backwards incompatible, but
since such objects were never really functional, it seems unlikely that
anybody will notice.
We will retain the --literally flag, as it also instructs hash-object
not to worry about other format issues (e.g., type-specific things that
fsck would complain about). The documentation does not need to be
updated, as it was always vague about which checks we're loosening (it
uses only the phrase "any garbage").
The code change is a bit hard to verify from just the patch text. We can
drop our local hash_literally() helper, but it was really just wrapping
write_object_file_literally(). We now replace that with calling
index_fd(), as we do for the non-literal code path, but dropping the
INDEX_FORMAT_CHECK flag. This ends up being the same semantically as
what the _literally() code path was doing (modulo handling unknown
types, which is our goal).
We'll be able to clean up these code paths a bit more in subsequent
patches.
The existing test is flipped to show that we now reject the unknown
type. The additional "extra-long type" test is now redundant, as we bail
early upon seeing a bogus type.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
When fsck-ing a loose object, we use object_info's type_name strbuf to
record the parsed object type as a string. For most objects this is
redundant with the object_type enum, but it does let us report the
string when we encounter an object with an unknown type (for which there
is no matching enum value).
There are a few downsides, though:
1. The code to report these cases is not actually robust. Since we did
not pass a strbuf to unpack_loose_header(), we only retrieved types
from headers up to 32 bytes. In longer cases, we'd simply say
"object corrupt or missing".
2. This is the last caller that uses object_info's type_name strbuf
support. It would be nice to refactor it so that we can simplify
that code.
3. Likewise, we'll check the hash of the object using its unknown type
(again, as long as that type is short enough). That depends on the
hash_object_file_literally() code, which we'd eventually like to
get rid of.
So we can simplify things by bailing immediately in read_loose_object()
when we encounter an unknown type. This has a few user-visible effects:
a. Instead of producing a single line of error output like this:
error: 26ed13ce3564fbbb44e35bde42c7da717ea004a6: object is of unknown type 'bogus': .git/objects/26/ed13ce3564fbbb44e35bde42c7da717ea004a6
we'll now issue two lines (the first from read_loose_object() when
we see the unparsable header, and the second from the fsck code,
since we couldn't read the object):
error: unable to parse type from header 'bogus 4' of .git/objects/26/ed13ce3564fbbb44e35bde42c7da717ea004a6
error: 26ed13ce3564fbbb44e35bde42c7da717ea004a6: object corrupt or missing: .git/objects/26/ed13ce3564fbbb44e35bde42c7da717ea004a6
This is a little more verbose, but this sort of error should be
rare (such objects are almost impossible to work with, and cannot
be transferred between repositories as they are not representable
in packfiles). And as a bonus, reporting the broken header in full
could help with debugging other cases (e.g., a header like "blob
xyzzy\0" would fail in parsing the size, but previously we'd not
have showed the offending bytes).
b. An object with an unknown type will be reported as corrupt, without
actually doing a hash check. Again, I think this is unlikely to
matter in practice since such objects are totally unusable.
We'll update one fsck test to match the new error strings. And we can
remove another test that covered the case of an object with an unknown
type _and_ a hash corruption. Since we'll skip the hash check now in
this case, the test is no longer interesting.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
Now that we no longer support OBJECT_INFO_ALLOW_UNKNOWN_TYPE, there is
no need to pass a strbuf into oid_object_info_extended() to record the
type. The regular object_type enum is sufficient to capture all of the
types we will allow.
This simplifies the code a bit, and will eventually let us drop
object_info's type_name strbuf support.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
The cat-file command has some minor support for handling objects with
"unknown" types. I.e., strings that are not "blob", "commit", "tree", or
"tag".
In theory this could be used for debugging or experimenting with
extensions to Git. But in practice this support is not very useful:
1. You can get the type and size of such objects, but nothing else.
Not even the contents!
2. Only loose objects are supported, since packfiles use numeric ids
for the types, rather than strings.
3. Likewise you cannot ever transfer objects between repositories,
because they cannot be represented in the packfiles used for the
on-the-wire protocol.
The support for these unknown types complicates the object-parsing code,
and has led to bugs such as b748ddb7a4 (unpack_loose_header(): fix
infinite loop on broken zlib input, 2025-02-25). So let's drop it.
The first step is to remove the user-facing parts, which are accessible
only via cat-file. This is technically backwards-incompatible, but given
the limitations listed above, these objects couldn't possibly be useful
in any workflow.
However, we can't just rip out the option entirely. That would hurt a
caller who ran:
git cat-file -t --allow-unknown-object <oid>
and fed it normal, well-formed objects. There --allow-unknown-type was
doing nothing, but we wouldn't want to start bailing with an error. So
to protect any such callers, we'll retain --allow-unknown-type as a
noop.
The code change is fairly small (but we'll able to clean up more code in
follow-on patches). The test updates drop any use of the option. We
still retain tests that feed the broken objects to cat-file without
--allow-unknown-type, as we should continue to confirm that those
objects are rejected. Note that in one spot we can drop a layer of loop,
re-indenting the body; viewing the diff with "-w" helps there.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
Make repository clean-up tasks "gc" can do available to "git
maintenance" front-end.
* ps/maintenance-missing-tasks:
builtin/maintenance: introduce "rerere-gc" task
builtin/gc: move rerere garbage collection into separate function
builtin/maintenance: introduce "worktree-prune" task
builtin/gc: move pruning of worktrees into a separate function
builtin/gc: remove global variables where it is trivial to do
builtin/gc: fix indentation of `cmd_gc()` parameters
|
|
As pointed out by CodeQL, `branch_get()` may return `NULL`, in which
case `branch_has_merge_config()` would return early, but we can even
avoid enumerating the refs prefixes in that case, saving even more CPU
cycles.
Technically, we should enclose these two statements in an `if (branch)
{...}` block, but the indentation is already quite deep, therefore I
refrained from doing that.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
As pointed out by CodeQL, it is a potentially dangerous practice to
store local variables' addresses in non-local structs. Yet this is
exactly what happens with the `acked_commits` attribute that is used in
`cmd_fetch()`: The pointer to a local variable is assigned to it.
Now, it is Git's convention that `cmd_*()` functions are essentially
only returning just before exiting the process, therefore there is
little danger that this attribute is used after the code flow returns
from that function.
However, code in `cmd_*()` function is often so useful that it gets
lifted into a library function, at which point this issue could become a
real problem.
Let's make sure to clear the `acked_commits` attribute out after it was
used, and before the function returns (at which point the address would
go stale).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
The difference of two unsigned integers is defined to be unsigned, and
therefore it is misleading to check whether it is greater than zero
(instead, the more natural way would be to check whether the difference
is zero or not).
Let's instead avoid the subtraction altogether, and compare the two
operands directly, which makes the code more obvious as a side effect.
Pointed out by CodeQL's rule with the ID
`cpp/unsigned-difference-expression-compared-zero`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|