The loose-objects task deletes loose objects that already exist in a
pack-file, then place the remaining loose objects into a new pack-file.
If this step runs all the time, then we risk creating pack-files with
very few objects with every 'git commit' process. To prevent
overwhelming the packs directory with small pack-files, place a minimum
number of objects to justify the task.
The 'maintenance.loose-objects.auto' config option specifies a minimum
number of loose objects to justify the task to run under the '--auto'
option. This defaults to 100 loose objects. Setting the value to zero
will prevent the step from running under '--auto' while a negative value
will force it to run every time.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
One goal of background maintenance jobs is to allow a user to
disable auto-gc (gc.auto=0) but keep their repository in a clean
state. Without any cleanup, loose objects will clutter the object
database and slow operations. In addition, the loose objects will
take up extra space because they are not stored with deltas against
similar objects.
Create a 'loose-objects' task for the 'git maintenance run' command.
This helps clean up loose objects without disrupting concurrent Git
commands using the following sequence of events:
1. Run 'git prune-packed' to delete any loose objects that exist
in a pack-file. Concurrent commands will prefer the packed
version of the object to the loose version. (Of course, there
are exceptions for commands that specifically care about the
location of an object. These are rare for a user to run on
purpose, and we hope a user that has selected background
maintenance will not be trying to do foreground maintenance.)
2. Run 'git pack-objects' on a batch of loose objects. These
objects are grouped by scanning the loose object directories in
lexicographic order until listing all loose objects -or-
reaching 50,000 objects. This is more than enough if the loose
objects are created only by a user doing normal development.
We noticed users with _millions_ of loose objects because VFS
for Git downloads blobs on-demand when a file read operation
requires populating a virtual file.
This step is based on a similar step in Scalar [1] and VFS for Git.
[1] https://github.com/microsoft/scalar/blob/master/Scalar.Common/Maintenance/LooseObjectsStep.cs
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When working with very large repositories, an incremental 'git fetch'
command can download a large amount of data. If there are many other
users pushing to a common repo, then this data can rival the initial
pack-file size of a 'git clone' of a medium-size repo.
Users may want to keep the data on their local repos as close as
possible to the data on the remote repos by fetching periodically in
the background. This can break up a large daily fetch into several
smaller hourly fetches.
The task is called "prefetch" because it is work done in advance
of a foreground fetch to make that 'git fetch' command much faster.
However, if we simply ran 'git fetch <remote>' in the background,
then the user running a foreground 'git fetch <remote>' would lose
some important feedback when a new branch appears or an existing
branch updates. This is especially true if a remote branch is
force-updated and this isn't noticed by the user because it occurred
in the background. Further, the functionality of 'git push
--force-with-lease' becomes suspect.
When running 'git fetch <remote> <options>' in the background, use
the following options for careful updating:
1. --no-tags prevents getting a new tag when a user wants to see
the new tags appear in their foreground fetches.
2. --refmap= removes the configured refspec which usually updates
refs/remotes/<remote>/* with the refs advertised by the remote.
While this looks confusing, this was documented and tested by
b40a50264a (fetch: document and test --refmap="", 2020-01-21),
including this sentence in the documentation:
Providing an empty `<refspec>` to the `--refmap` option
causes Git to ignore the configured refspecs and rely
entirely on the refspecs supplied as command-line arguments.
3. By adding a new refspec "+refs/heads/*:refs/prefetch/<remote>/*"
we can ensure that we actually load the new values somewhere in
our refspace while not updating refs/heads or refs/remotes. By
storing these refs here, the commit-graph job will update the
commit-graph with the commits from these hidden refs.
4. --prune will delete the refs/prefetch/<remote> refs that no
longer appear on the remote.
5. --no-write-fetch-head prevents updating FETCH_HEAD.
We've been using this step as a critical background job in Scalar
[1] (and VFS for Git). This solved a pain point that was showing up
in user reports: fetching was a pain! Users do not like waiting to
download the data that was created while they were away from their
machines. After implementing background fetch, the foreground fetch
commands sped up significantly because they mostly just update refs
and download a small amount of new data. The effect is especially
dramatic when paried with --no-show-forced-udpates (through
fetch.showForcedUpdates=false).
[1] https://github.com/microsoft/scalar/blob/master/Scalar.Common/Maintenance/FetchStep.cs
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of writing a new commit-graph in every 'git maintenance run
--auto' process (when maintenance.commit-graph.enalbed is configured to
be true), only write when there are "enough" commits not in a
commit-graph file.
This count is controlled by the maintenance.commit-graph.auto config
option.
To compute the count, use a depth-first search starting at each ref, and
leaving markers using the SEEN flag. If this count reaches the limit,
then terminate early and start the task. Otherwise, this operation will
peel every ref and parse the commit it points to. If these are all in
the commit-graph, then this is typically a very fast operation. Users
with many refs might feel a slow-down, and hence could consider updating
their limit to be very small. A negative value will force the step to
run every time.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'git maintenance run' command has an '--auto' option. This is used
by other Git commands such as 'git commit' or 'git fetch' to check if
maintenance should be run after adding data to the repository.
Previously, this --auto option was only used to add the argument to the
'git gc' command as part of the 'gc' task. We will be expanding the
other tasks to perform a check to see if they should do work as part of
the --auto flag, when they are enabled by config.
First, update the 'gc' task to perform the auto check inside the
maintenance process. This prevents running an extra 'git gc --auto'
command when not needed. It also shows a model for other tasks.
Second, use the 'auto_condition' function pointer as a signal for
whether we enable the maintenance task under '--auto'. For instance, we
do not want to enable the 'fetch' task in '--auto' mode, so that
function pointer will remain NULL.
Now that we are not automatically calling 'git gc', a test in
t5514-fetch-multiple.sh must be changed to watch for 'git maintenance'
instead.
We continue to pass the '--auto' option to the 'git gc' command when
necessary, because of the gc.autoDetach config option changes behavior.
Likely, we will want to absorb the daemonizing behavior implied by
gc.autoDetach as a maintenance.autoDetach config option.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently, a normal run of "git maintenance run" will only run the 'gc'
task, as it is the only one enabled. This is mostly for backwards-
compatible reasons since "git maintenance run --auto" commands replaced
previous "git gc --auto" commands after some Git processes. Users could
manually run specific maintenance tasks by calling "git maintenance run
--task=<task>" directly.
Allow users to customize which steps are run automatically using config.
The 'maintenance.<task>.enabled' option then can turn on these other
tasks (or turn off the 'gc' task).
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Performing maintenance on a Git repository involves writing data to the
.git directory, which is not safe to do with multiple writers attempting
the same operation. Ensure that only one 'git maintenance' process is
running at a time by holding a file-based lock. Simply the presence of
the .git/maintenance.lock file will prevent future maintenance. This
lock is never committed, since it does not represent meaningful data.
Instead, it is only a placeholder.
If the lock file already exists, then no maintenance tasks are
attempted. This will become very important later when we implement the
'prefetch' task, as this is our stop-gap from creating a recursive process
loop between 'git fetch' and 'git maintenance run --auto'.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A user may want to only run certain maintenance tasks in a certain
order. Add the --task=<task> option, which allows a user to specify an
ordered list of tasks to run. These cannot be run multiple times,
however.
Here is where our array of maintenance_task pointers becomes critical.
We can sort the array of pointers based on the task order, but we do not
want to move the struct data itself in order to preserve the hashmap
references. We use the hashmap to match the --task=<task> arguments into
the task struct data.
Keep in mind that the 'enabled' member of the maintenance_task struct is
a placeholder for a future 'maintenance.<task>.enabled' config option.
Thus, we use the 'enabled' member to specify which tasks are run when
the user does not specify any --task=<task> arguments. The 'enabled'
member should be ignored if --task=<task> appears.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The first new task in the 'git maintenance' builtin is the
'commit-graph' task. This updates the commit-graph file
incrementally with the command
git commit-graph write --reachable --split
By writing an incremental commit-graph file using the "--split"
option we minimize the disruption from this operation. The default
behavior is to merge layers until the new "top" layer is less than
half the size of the layer below. This provides quick writes most
of the time, with the longer writes following a power law
distribution.
Most importantly, concurrent Git processes only look at the
commit-graph-chain file for a very short amount of time, so they
will verly likely not be holding a handle to the file when we try
to replace it. (This only matters on Windows.)
If a concurrent process reads the old commit-graph-chain file, but
our job expires some of the .graph files before they can be read,
then those processes will see a warning message (but not fail).
This could be avoided by a future update to use the --expire-time
argument when writing the commit-graph.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In anticipation of implementing multiple maintenance tasks inside the
'maintenance' builtin, use a list of structs to describe the work to be
done.
The struct maintenance_task stores the name of the task (as given by a
future command-line argument) along with a function pointer to its
implementation and a boolean for whether the step is enabled.
A list these structs are initialized with the full list of implemented
tasks along with a default order. For now, this list only contains the
"gc" task. This task is also the only task enabled by default.
The run subcommand will return a nonzero exit code if any task fails.
However, it will attempt all tasks in its loop before returning with the
failure. Also each failed task will print an error message.
Helped-by: Taylor Blau <me@ttaylorr.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The run_auto_gc() method is used in several places to trigger a check
for repo maintenance after some Git commands, such as 'git commit' or
'git fetch'.
To allow for extra customization of this maintenance activity, replace
the 'git gc --auto [--quiet]' call with one to 'git maintenance run
--auto [--quiet]'. As we extend the maintenance builtin with other
steps, users will be able to select different maintenance activities.
Rename run_auto_gc() to run_auto_maintenance() to be clearer what is
happening on this call, and to expose all callers in the current diff.
Rewrite the method to use a struct child_process to simplify the calls
slightly.
Since 'git fetch' already allows disabling the 'git gc --auto'
subprocess, add an equivalent option with a different name to be more
descriptive of the new behavior: '--[no-]maintenance'. Update the
documentation to include these options at the same time.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Maintenance activities are commonly used as steps in larger scripts.
Providing a '--quiet' option allows those scripts to be less noisy when
run on a terminal window. Turn this mode on by default when stderr is
not a terminal.
Pipe the option to the 'git gc' child process.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'gc' builtin is our current entrypoint for automatically maintaining
a repository. This one tool does many operations, such as repacking the
repository, packing refs, and rewriting the commit-graph file. The name
implies it performs "garbage collection" which means several different
things, and some users may not want to use this operation that rewrites
the entire object database.
Create a new 'maintenance' builtin that will become a more general-
purpose command. To start, it will only support the 'run' subcommand,
but will later expand to add subcommands for scheduling maintenance in
the background.
For now, the 'maintenance' builtin is a thin shim over the 'gc' builtin.
In fact, the only option is the '--auto' toggle, which is handed
directly to the 'gc' builtin. The current change is isolated to this
simple operation to prevent more interesting logic from being lost in
all of the boilerplate of adding a new builtin.
Use existing builtin/gc.c file because we want to share code between the
two builtins. It is possible that we will have 'maintenance' replace the
'gc' builtin entirely at some point, leaving 'git gc' as an alias for
some specific arguments to 'git maintenance run'.
Create a new test_subcommand helper that allows us to test if a certain
subcommand was run. It requires storing the GIT_TRACE2_EVENT logs in a
file. A negation mode is available that will be used in later tests.
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If you run fetch but record the result in remote-tracking branches,
and either if you do nothing with the fetched refs (e.g. you are
merely mirroring) or if you always work from the remote-tracking
refs (e.g. you fetch and then merge origin/branchname separately),
you can get away with having no FETCH_HEAD at all.
Teach "git fetch" a command line option "--[no-]write-fetch-head".
The default is to write FETCH_HEAD, and the option is primarily
meant to be used with the "--no-" prefix to override this default,
because there is no matching fetch.writeFetchHEAD configuration
variable to flip the default to off (in which case, the positive
form may become necessary to defeat it).
Note that under "--dry-run" mode, FETCH_HEAD is never written;
otherwise you'd see list of objects in the file that you do not
actually have. Passing `--write-fetch-head` does not force `git
fetch` to write the file.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Earlier, to countermand the implicit "-m" option when the
"--first-parent" option is used with "git log", we added the
"--[no-]diff-merges" option in the jk/log-fp-implies-m topic. To
leave the door open to allow the "--diff-merges" option to take
values that instructs how patches for merge commits should be
computed (e.g. "cc"? "-p against first parent?"), redefine
"--diff-merges" to take non-optional value, and implement "off"
that means the same thing as "--no-diff-merges".
* so/log-diff-merges-opt:
t/t4013: add test for --diff-merges=off
doc/git-log: describe --diff-merges=off
revision: change "--diff-merges" option to require parameter
"git log --first-parent -p" showed patches only for single-parent
commits on the first-parent chain; the "--first-parent" option has
been made to imply "-m". Use "--no-diff-merges" to restore the
previous behaviour to omit patches for merge commits.
* jk/log-fp-implies-m:
doc/git-log: clarify handling of merge commit diffs
doc/git-log: move "-t" into diff-options list
doc/git-log: drop "-r" diff option
doc/git-log: move "Diff Formatting" from rev-list-options
log: enable "-m" automatically with "--first-parent"
revision: add "--no-diff-merges" option to counteract "-m"
log: drop "--cc implies -m" logic
Recent versions of "git diff-files" shows a diff between the index
and the working tree for "intent-to-add" paths as a "new file"
patch; "git apply --cached" should be able to take "git diff-files"
and should act as an equivalent to "git add" for the path, but the
command failed to do so for such a path.
* rp/apply-cached-with-i-t-a:
t4140: test apply with i-t-a paths
apply: make i-t-a entries never match worktree
apply: allow "new file" patches on i-t-a entries
"git bisect" learns the "--first-parent" option to find the first
breakage along the first-parent chain.
* al/bisect-first-parent:
bisect: combine args passed to find_bisection()
bisect: introduce first-parent flag
cmd_bisect__helper: defer parsing no-checkout flag
rev-list: allow bisect and first-parent flags
t6030: modernize "git bisect run" tests
A no-op replacement function implemented as a C preprocessor macro
does not perform as good a job as one implemented as a "static
inline" function in catching errors in parameters; replace the
former with the latter in <git-compat-util.h> header.
* jc/noop-with-static-inline:
compat-util: type-check parameters of no-op replacement functions
The existing backends for "git mergetool" based on variants of vim
have been refactored and then support for "nvim" has been added.
* pd/mergetool-nvimdiff:
mergetools: add support for nvimdiff (neovim) family
mergetool--lib: improve support for vimdiff-style tool variants
Further preliminary change to refs API.
* hn/reftable-prep-part-2:
Make HEAD a PSEUDOREF rather than PER_WORKTREE.
Modify pseudo refs through ref backend storage
t1400: use git rev-parse for testing PSEUDOREF existence
Stop when "sendmail.*" configuration variables are defined, which
could be a mistaken attempt to define "sendemail.*" variables.
* dd/send-email-config:
git-send-email: die if sendmail.* config is set
The logic to find the ref transaction hook script attempted to
cache the path to the found hook without realizing that it needed
to keep a copied value, as the API it used returned a transitory
buffer space. This has been corrected.
* ps/ref-transaction-hook:
t1416: avoid hard-coded sha1 ids
refs: fix interleaving hook calls with reference-transaction hook
The "git blame --first-parent" option was not documented, but now
it is.
* rp/blame-first-parent-doc:
blame-options.txt: document --first-parent option
A new helper function has_object() has been introduced to make it
easier to mark object existence checks that do and don't want to
trigger lazy fetches, and a few such checks are converted using it.
* jt/has_object:
fsck: do not lazy fetch known non-promisor object
pack-objects: no fetch when allow-{any,promisor}
apply: do not lazy fetch when applying binary
sha1-file: introduce no-lazy-fetch has_object()
CMake support to build with MSVC for Windows bypassing the Makefile.
* ss/cmake-build:
ci: modification of main.yml to use cmake for vs-build job
cmake: support for building git on windows with msvc and clang.
cmake: support for building git on windows with mingw
cmake: support for testing git when building out of the source tree
cmake: support for testing git with ctest
cmake: installation support for git
cmake: generate the shell/perl/python scripts and templates, translations
Introduce CMake support for configuring Git
The component to respond to "git fetch" request is made more
configurable to selectively allow or reject object filtering
specification used for partial cloning.
* tb/upload-pack-filters:
t5616: use test_i18ngrep for upload-pack errors
upload-pack.c: introduce 'uploadpackfilter.tree.maxDepth'
upload-pack.c: allow banning certain object filter(s)
list_objects_filter_options: introduce 'list_object_filter_config_name'
Doc cleanup around "worktree".
* es/worktree-doc-cleanups:
git-worktree.txt: link to man pages when citing other Git commands
git-worktree.txt: make start of new sentence more obvious
git-worktree.txt: fix minor grammatical issues
git-worktree.txt: consistently use term "working tree"
git-worktree.txt: employ fixed-width typeface consistently
The final leg of SHA-256 transition.
* bc/sha-256-part-3: (39 commits)
t: remove test_oid_init in tests
docs: add documentation for extensions.objectFormat
ci: run tests with SHA-256
t: make SHA1 prerequisite depend on default hash
t: allow testing different hash algorithms via environment
t: add test_oid option to select hash algorithm
repository: enable SHA-256 support by default
setup: add support for reading extensions.objectformat
bundle: add new version for use with SHA-256
builtin/verify-pack: implement an --object-format option
http-fetch: set up git directory before parsing pack hashes
t0410: mark test with SHA1 prerequisite
t5308: make test work with SHA-256
t9700: make hash size independent
t9500: ensure that algorithm info is preserved in config
t9350: make hash size independent
t9301: make hash size independent
t9300: use $ZERO_OID instead of hard-coded object ID
t9300: abstract away SHA-1-specific constants
t8011: make hash size independent
...
--diff-merges=off is the only accepted form for now, a synonym for
--no-diff-merges.
This patch is a preparation for adding more values, as well as supporting
--diff-merges=<parent>, where <parent> is single parent number to output diff
against.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The test added by e5256c82e5 (refs: fix interleaving hook calls with
reference-transaction hook, 2020-08-07) uses hard-coded sha1 object ids
in its expected output. This causes it to fail when run with
GIT_TEST_DEFAULT_HASH=sha256.
Let's make use of the oid variables we define earlier, as the rest of
the nearby tests do.
Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In `stop_progress()`, we're careful to check that `p_progress` is
non-NULL before we dereference it, but by then we have already
dereferenced it when calling `finish_if_sparse(*p_progress)`. And, for
what it's worth, we'll go on to blindly dereference it again inside
`stop_progress_msg()`.
We could return early if we get a NULL-pointer, but let's go one step
further and BUG instead. The progress API handles NULL just fine, but
that's the NULL-ness of `*p_progress`, e.g., when running with
`--no-progress`. If `p_progress` is NULL, chances are that's a mistake.
For symmetry, let's do the same check in `stop_progress_msg()`, too.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update "git help guides" documentation organization.
* pb/guide-docs:
git.txt: add list of guides
Documentation: don't hardcode command categories twice
help: drop usage of 'common' and 'useful' for guides
command-list.txt: add missing 'gitcredentials' and 'gitremote-helpers'
All "mergy" operations that internally use the merge-recursive
machinery should honor the merge.renormalize configuration, but
many of them didn't.
* en/eol-attrs-gotchas:
checkout: support renormalization with checkout -m <paths>
merge: make merge.renormalize work for all uses of merge machinery
t6038: remove problematic test
t6038: make tests fail for the right reason
Small fixes and workarounds.
* jk/compiler-fixes-and-workarounds:
revision: avoid leak when preparing bloom filter for "/"
revision: avoid out-of-bounds read/write on empty pathspec
config: work around gcc-10 -Wstringop-overflow warning
Adjust tests in contrib/ to the recent change to fmt-merge-msg.
* es/adjust-subtree-test-for-merge-msg-update:
Revert "contrib: subtree: adjust test to change in fmt-merge-msg"
Derrick Stolee