More FAQ entries.
* bc/faq-misc:
docs: explain how to deal with files that are always modified
docs: explain why reverts are not always applied on merge
docs: explain why squash merges are broken with long-running branches
Some combinations of command-line options to `git clone` are invalid,
but there were previously no tests ensuring those combinations reported
errors. Similarly, `git clone --template` didn't appear to have any
tests.
Helped-by: Jeff King <peff@peff.net>
Helped-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Sean Barag <sean@barag.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Get rid of 'dense' argument that is redundant for every function that has
'struct rev_info *rev' argument as well, as the value of 'dense' passed is
always taken from 'rev->dense_combined_merges' field.
The only place where this was not the case is in 'submodule.c' where
'diff_tree_combined_merge()' was called with '1' for 'dense' argument. However,
at that call the 'revs' instance used is local to the function, and we now just
set 'revs->dense_combined_merges' to 1 in this local instance.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When add_delta_base_cache() is called with a base that is already in the
cache, no operation is performed. But the check is done after allocating
space for a new entry, so we end up leaking memory on the early return.
In addition, the caller never free()'s the base as it expects the
function to take ownership of it. But the base is not released when we
skip insertion, so it also gets leaked. To fix these problems, move the
allocation of a new entry further down in add_delta_base_cache(), and
free() the base on early return.
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The third phase of unpack_entry() performs the following sequence in a
loop, until all the deltas enumerated in phase one are applied and the
entry is fully reconstructed:
1. Add the current base entry to the delta base cache
2. Unpack the next delta
3. Patch the unpacked delta on top of the base
When the optional object reading lock is enabled, the above steps will
be performed while holding the lock. However, step 2. momentarily
releases it so that inflation can be performed in parallel for increased
performance. Because the `base` buffer inserted in the cache at 1. is
not duplicated, another thread can potentially free() it while the lock
is released at 2. (e.g. when there is no space left in the cache to
insert another entry). In this case, the later attempt to dereference
`base` at 3. will cause a segmentation fault. This problem was observed
during a multithreaded git-grep execution on a repository with large
objects.
To fix the race condition (and later segmentation fault), let's reorder
the aforementioned steps so that `base` is only added to the cache at
the end. This will prevent the buffer from being released by another
thread while it is still in use. An alternative solution which would not
require the reordering would be to duplicate `base` before inserting it
in the cache. However, as Phil Hord mentioned, memcpy()'ing large bases
can negatively affect performance: in his experiments, this alternative
approach slowed git-grep down by 10% to 20%.
Reported-by: Phil Hord <phil.hord@gmail.com>
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a fetch with the --filter argument is made, the configured default
filter is set even if one already exists. This change was made in
5e46139376 ("builtin/fetch: remove unique promisor remote limitation",
2019-06-25) - in particular, changing from:
* If this is the FIRST partial-fetch request, we enable partial
* on this repo and remember the given filter-spec as the default
* for subsequent fetches to this remote.
to:
* If this is a partial-fetch request, we enable partial on
* this repo if not already enabled and remember the given
* filter-spec as the default for subsequent fetches to this
* remote.
(The given filter-spec is "remembered" even if there is already an
existing one.)
This is problematic whenever a lazy fetch is made, because lazy fetches
are made using "git fetch --filter=blob:none", but this will also happen
if the user invokes "git fetch --filter=<filter>" manually. Therefore,
restore the behavior prior to 5e46139376, which writes a filter-spec
only if the current fetch request is the first partial-fetch one (for
that remote).
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The text tries to say the code accepts many variations that look remotely
like scissors and perforation marks, but gives too little detail for users
to decide what is and what is not taken as a scissors line for themselves.
Instead of describing the heuristics more, just spell out what will always
be accepted, namely "-- >8 --", as it would not help users to give them
more choices and flexibility and be "creative" in their scissors line.
Signed-off-by: Evan Gates <evan.gates@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On Windows, we use the `vcpkg` project to manage the dependencies, via
`compat/vcbuild/`. Let's make sure that these dependencies are found by
default.
This is needed because we are about to recommend loading the Git
worktree as a folder into Visual Studio, relying on the automatic CMake
support (which would make it relatively cumbersome to adjust the search
path used by CMake manually).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
By default, Git for Windows does not install its `sh.exe` into the
`PATH`. However, our current `CMakeLists.txt` expects to find a shell
interpreter in the `PATH`.
So let's fall back to looking in the default location where Git for
Windows _does_ install a relatively convenient `sh.exe`:
`C:\Program Files\Git\bin\sh.exe`
Helped-by: Øystein Walle <oystwa@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
That should be a ":", not a second "=". While at it, refer to the
placeholder "<n>" as "<n>", not "n" (see, e.g., the entry just before
this one).
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We document how `merge.suppressDest` can be used to omit " into <branch
name>" from the title of the merge message. It is true that we omit the
space character before "into", but that lone double quote character
risks ending up on the wrong side of a line break, looking a bit out of
place. This currently happens with, e.g., 80-character terminals.
Drop that leading quoted space. The result should be just as clear about
how this option affects the formatted message.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of checking for "refs/heads/" using `starts_with()`, then
skipping past "refs/heads/" using `strlen()`, just use `skip_prefix()`.
In `is_worktree_being_rebased()`, we can adjust the indentation while
we're here and lose a pair of parentheses which isn't needed and which
might even make the reader wonder what they're missing and why that
grouping is there.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As the commit message of 04a3dfb8b5 ("worktree.c: check whether branch
is bisected in another worktree", 2016-04-22) indicates, the function
`is_worktree_being_bisected()` is based on the older function
`is_worktree_being_rebased()`. This heritage can also be seen in the
name of the variable where we store our return value: It was never
adapted while copy-editing and remains as `found_rebase`.
Rename the variable to make clear that we're looking for a bisect(ion),
nothing else.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The comment above `add_head_info()` mentions "head_sha1", but it was
renamed to "head_oid" in 0f05154c70 ("worktree: convert struct worktree
to object_id", 2017-10-15). Update the comment.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We have `strbuf_worktree_ref()`, which works on a strbuf, and a wrapper
for it, `worktree_ref()` which returns a string. We even make this
wrapper available through worktree.h. But it only has a single caller,
sitting right next to it in worktree.c.
Just inline the wrapper into its only caller. This means the caller can
quite naturally reuse a single strbuf. We currently achieve something
similar by having a static strbuf in the wrapper.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we have a `struct wt_status_state`, we manually free its `branch`,
`onto` and `detached_from`, or sometimes just one or two of them.
Provide a function `wt_status_state_free_buffers()` which does the
freeing.
The callers are still aware of these fields, e.g., they check whether
`branch` was populated or not. But this way, they don't need to know
about *all* of them, and if `struct wt_status_state` gets more fields,
they will not need to learn to free them.
Users of `struct wt_status` (which contains a `wt_status_state`) already
have `wt_status_collect_free_buffers()` (corresponding to
`wt_status_collect()`) which we can also teach to use this new helper.
Finally, note that we're currently leaving dangling pointers behind.
Some callers work on a stack-allocated struct, where this is obviously
ok. But for the users of `run_status()` in builtin/commit.c, there are
ample opportunities for someone to mistakenly use those dangling
pointers. We seem to be ok for now, but it's a use-after-free waiting to
happen. Let's leave NULL-pointers behind instead.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We pass around a `FILE *` in the `struct wt_status` and almost always
print to it. But in a few places, we write to `stdout` instead, either
explicitly through `fprintf(stdout, ...)` or implicitly with
`printf(...)` (and a few `putchar(...)`).
Always be explicit about writing to `s->fp`. To the best of my
understanding, this never mattered in practice because these spots are
involved in various forms of `git status` which always end up at
standard output anyway. When we do write to another file, it's because
we're creating a commit message template, and these code paths aren't
involved.
But let's be consistent to help future readers and avoid future bugs.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`abbrev_sha1_in_line()` uses a `struct object_id oid` and should be
fully prepared to handle non-SHA1 object ids. Rename it to
`abbrev_oid_in_line()`.
A few comments in `wt_status_get_detached_from()` mention "sha1". The
variable they refer to was renamed in e86ab2c1cd ("wt-status: convert to
struct object_id", 2017-02-21). Update the comments to reference "oid"
instead.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that shortlog supports reading from trailers, it can be useful to
combine counts from multiple trailers, or between trailers and authors.
This can be done manually by post-processing the output from multiple
runs, but it's non-trivial to make sure that each name/commit pair is
counted only once.
This patch teaches shortlog to accept multiple --group options on the
command line, and pull data from all of them. That makes it possible to
run:
git shortlog -ns --group=author --group=trailer:co-authored-by
to get a shortlog that counts authors and co-authors equally.
The implementation is mostly straightforward. The "group" enum becomes a
bitfield, and the trailer key becomes a list. I didn't bother
implementing the multi-group semantics for reading from stdin. It would
be possible to do, but the existing matching code makes it awkward, and
I doubt anybody cares.
The duplicate suppression we used for trailers now covers authors and
committers as well (though in non-trailer single-group mode we can skip
the hash insertion and lookup, since we only see one value per commit).
There is one subtlety: we now care about the case when no group bit is
set (in which case we default to showing the author). The caller in
builtin/log.c needs to be adapted to ask explicitly for authors, rather
than relying on shortlog_init(). It would be possible with some
gymnastics to make this keep working as-is, but it's not worth it for a
single caller.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Trailers don't necessarily contain name/email identity values, so
shortlog has so far treated them as opaque strings. However, since many
trailers do contain identities, it's useful to treat them as such when
they can be parsed. That lets "-e" work as usual, as well as mailmap.
When they can't be parsed, we'll continue with the old behavior of
treating them as a single string (there's no new test for that here,
since the existing tests cover a trailer like this).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function is actually useful for parsing any identity, whether from
stdin or not. We'll need it for handling trailers.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The current documentation is vague about what happens with
--group=trailer:signed-off-by when we see a commit with:
Signed-off-by: One
Signed-off-by: Two
Signed-off-by: One
We clearly should credit both "One" and "Two", but should "One" get
credited twice? The current code does so, but mostly because that was
the easiest thing to do. It's probably more useful to count each commit
at most once. This will become especially important when we allow
values from multiple sources in a future patch.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If a project uses commit trailers, this patch lets you use
shortlog to see who is performing each action. For example,
running:
git shortlog -ns --group=trailer:reviewed-by
in git.git shows who has reviewed. You can even use a custom
format to see things like who has helped whom:
git shortlog --format="...helped %an (%ad)" \
--group=trailer:helped-by
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The trailer code knows how to parse out the trailers and re-format them,
but there's no easy way to iterate over the trailers (you can use
trailer_info, but you have to then do a bunch of extra parsing).
Let's add an iteration interface that makes this easy to do.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In preparation for adding more grouping types, let's refactor the
committer/author grouping code and add a user-facing option that binds
them together. In particular:
- the main option is now "--group", to make it clear
that the various group types are mutually exclusive. The
"--committer" option is an alias for "--group=committer".
- we keep an enum rather than a binary flag, to prepare
for more values
- we prefer switch statements to ternary assignment, since
other group types will need more custom code
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The completion tests used that name unnecessarily, and it is a
non-inclusive term, so let's avoid using it here.
Since three of the touched test cases make use of the fact that two of
the branch names (`master` and `maint`) start with the same letter (or
even with the same two letters), we choose to replace the use of
`master` by a name that also has that property: `main`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The term `master` has a loaded history that serves as a constant
reminder of racial injustice. The Git project has no desire to
perpetuate this and already started avoiding it.
The test suite uses variations of this name for branches other than the
default one. Apart from t3200, where we just addressed this in the
previous commit, those instances can be renamed in an automated manner
because they do not require any changes outside of the test script, so
let's do that.
Seeing as the touched branches have very little (if anything) to do with
the default branch, we choose to use a completely separate naming
scheme: `topic_<number>` (it cannot be `topic-<number>` because t5515
uses the `test_oid` machinery with the term, and that machinery uses
shell variables internally, whose names cannot contain dashes).
This trick was performed by this (GNU) sed invocation:
$ sed -i 's/master\([a-z0-9]\)/topic_\1/g' t/t*.sh
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
21bf933928 (ref-filter: allow merged and no-merged filters, 2020-09-15)
added an early return to reach_filter(). Avoid leaking the memory of a
then unused array by postponing its allocation until we know we need it.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently only the long version (--source=) supports completion.
Add completion support to the short (-s) option too.
Signed-off-by: Ákos Uzonyi <uzonyi.akos@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In both _git_checkout and _git_switch a new "prevword" variable were
introduced, however the "prev" variable already contains the last word.
The "prevword" variable is replaced with "prev", and the case is moved
to the beginning of the function, like it's done in many other places
(e.g. _git_commit). Also the indentaion of the case is fixed.
Signed-off-by: Ákos Uzonyi <uzonyi.akos@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"diff-highlight" (in contrib/) had a logic to flush its output upon
seeing a blank line but the way it detected a blank line was broken.
* jk/diff-highlight-blank-match-fix:
diff-highlight: correctly match blank lines for flush
"git push" that wants to be atomic and wants to send push
certificate learned not to prepare and sign the push certificate
when it fails the local check (hence due to atomicity it is known
that no certificate is needed).
* hx/push-atomic-with-cert:
send-pack: run GPG after atomic push checking
The "unshelve" subcommand of "git p4" used incorrectly used
commit^N where it meant to say commit~N to name the Nth generation
ancestor, which has been corrected.
* ld/p4-unshelve-fix:
git-p4: use HEAD~$n to find parent commit for unshelve
git-p4 unshelve: adding a commit breaks git-p4 unshelve
"git receive-pack" that accepts requests by "git push" learned to
outsource most of the ref updates to the new "proc-receive" hook.
* jx/proc-receive-hook:
doc: add documentation for the proc-receive hook
transport: parse report options for tracking refs
t5411: test updates of remote-tracking branches
receive-pack: new config receive.procReceiveRefs
doc: add document for capability report-status-v2
New capability "report-status-v2" for git-push
receive-pack: feed report options to post-receive
receive-pack: add new proc-receive hook
t5411: add basic test cases for proc-receive hook
transport: not report a non-head push as a branch
A "git gc"'s big brother has been introduced to take care of more
repository maintenance tasks, not limited to the object database
cleaning.
* ds/maintenance-part-1:
maintenance: add trace2 regions for task execution
maintenance: add auto condition for commit-graph task
maintenance: use pointers to check --auto
maintenance: create maintenance.<task>.enabled config
maintenance: take a lock on the objects directory
maintenance: add --task option
maintenance: add commit-graph task
maintenance: initialize task array
maintenance: replace run_auto_gc()
maintenance: add --quiet option
maintenance: create basic maintenance runner
The object name written to this file is not exposed to end-users and
the only reader of this file immediately expands it back to a full
object name. Stop abbreviating while writing, and expect a full
object name while reading, which simplifies the code a bit.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Because these constructs can be used to parse user input to be
passed to rev-list --objects, e.g.
range=$(git rev-parse v1.0..v2.0) &&
git rev-list --objects $range | git pack-objects --stdin
the endpoints (v1.0 and v2.0 in the example) are shown without
peeling them to underlying commits, even when they are annotated
tags. Make sure it stays that way.
While at it, ensure "rev-parse A...B" also keeps the endpoints A and
B unpeeled, even though the negative side (i.e. the merge-base
between A and B) has to become a commit.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Protocol v2 became the default in v2.26.0 via 684ceae32d (fetch: default
to protocol version 2, 2019-12-23). More widespread use turned up a
regression in negotiation. That was fixed in v2.27.0 via 4fa3f00abb
(fetch-pack: in protocol v2, in_vain only after ACK, 2020-04-27), but we
also reverted the default to v0 as a precuation in 11c7f2a30b (Revert
"fetch: default to protocol version 2", 2020-04-22).
In v2.28.0, we re-enabled it for experimental users with 3697caf4b9
(config: let feature.experimental imply protocol.version=2, 2020-05-20)
and haven't heard any complaints. v2.28 has only been out for 2 months,
but I'd generally expect people turning on feature.experimental to also
stay pretty up-to-date. So we're not likely to collect much more data by
waiting. In addition, we have no further reports from people running
v2.26.0, and of course some people have been setting protocol.version
manually for ages.
Let's move forward with v2 as the default again. It's possible there are
still lurking bugs, but we won't know until it gets more widespread use.
And we can find and squash them just like any other bug at this point.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The incremental-repack task updates the multi-pack-index by deleting pack-
files that have been replaced with new packs, then repacking a batch of
small pack-files into a larger pack-file. This incremental repack is faster
than rewriting all object data, but is slower than some other
maintenance activities.
The 'maintenance.incremental-repack.auto' config option specifies how many
pack-files should exist outside of the multi-pack-index before running
the step. These pack-files could be created by 'git fetch' commands or
by the loose-objects task. The default value is 10.
Setting the option to zero disables the task with the '--auto' option,
and a negative value makes the task run every time.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When repacking during the 'incremental-repack' task, we use the
--batch-size option in 'git multi-pack-index repack'. The initial setting
used --batch-size=0 to repack everything into a single pack-file. This is
not sustainable for a large repository. The amount of work required is
also likely to use too many system resources for a background job.
Update the 'incremental-repack' task by dynamically computing a
--batch-size option based on the current pack-file structure.
The dynamic default size is computed with this idea in mind for a client
repository that was cloned from a very large remote: there is likely one
"big" pack-file that was created at clone time. Thus, do not try
repacking it as it is likely packed efficiently by the server.
Instead, we select the second-largest pack-file, and create a batch size
that is one larger than that pack-file. If there are three or more
pack-files, then this guarantees that at least two will be combined into
a new pack-file.
Of course, this means that the second-largest pack-file size is likely
to grow over time and may eventually surpass the initially-cloned
pack-file. Recall that the pack-file batch is selected in a greedy
manner: the packs are considered from oldest to newest and are selected
if they have size smaller than the batch size until the total selected
size is larger than the batch size. Thus, that oldest "clone" pack will
be first to repack after the new data creates a pack larger than that.
We also want to place some limits on how large these pack-files become,
in order to bound the amount of time spent repacking. A maximum
batch-size of two gigabytes means that large repositories will never be
packed into a single pack-file using this job, but also that repack is
rather expensive. This is a trade-off that is valuable to have if the
maintenance is being run automatically or in the background. Users who
truly want to optimize for space and performance (and are willing to pay
the upfront cost of a full repack) can use the 'gc' task to do so.
Create a test for this two gigabyte limit by creating an EXPENSIVE test
that generates two pack-files of roughly 2.5 gigabytes in size, then
performs an incremental repack. Check that the --batch-size argument in
the subcommand uses the hard-coded maximum.
Helped-by: Chris Torek <chris.torek@gmail.com>
Reported-by: Son Luong Ngoc <sluongng@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous change cleaned up loose objects using the
'loose-objects' that can be run safely in the background. Add a
similar job that performs similar cleanups for pack-files.
One issue with running 'git repack' is that it is designed to
repack all pack-files into a single pack-file. While this is the
most space-efficient way to store object data, it is not time or
memory efficient. This becomes extremely important if the repo is
so large that a user struggles to store two copies of the pack on
their disk.
Instead, perform an "incremental" repack by collecting a few small
pack-files into a new pack-file. The multi-pack-index facilitates
this process ever since 'git multi-pack-index expire' was added in
19575c7 (multi-pack-index: implement 'expire' subcommand,
2019-06-10) and 'git multi-pack-index repack' was added in ce1e4a1
(midx: implement midx_repack(), 2019-06-10).
The 'incremental-repack' task runs the following steps:
1. 'git multi-pack-index write' creates a multi-pack-index file if
one did not exist, and otherwise will update the multi-pack-index
with any new pack-files that appeared since the last write. This
is particularly relevant with the background fetch job.
When the multi-pack-index sees two copies of the same object, it
stores the offset data into the newer pack-file. This means that
some old pack-files could become "unreferenced" which I will use
to mean "a pack-file that is in the pack-file list of the
multi-pack-index but none of the objects in the multi-pack-index
reference a location inside that pack-file."
2. 'git multi-pack-index expire' deletes any unreferenced pack-files
and updaes the multi-pack-index to drop those pack-files from the
list. This is safe to do as concurrent Git processes will see the
multi-pack-index and not open those packs when looking for object
contents. (Similar to the 'loose-objects' job, there are some Git
commands that open pack-files regardless of the multi-pack-index,
but they are rarely used. Further, a user that self-selects to
use background operations would likely refrain from using those
commands.)
3. 'git multi-pack-index repack --bacth-size=<size>' collects a set
of pack-files that are listed in the multi-pack-index and creates
a new pack-file containing the objects whose offsets are listed
by the multi-pack-index to be in those objects. The set of pack-
files is selected greedily by sorting the pack-files by modified
time and adding a pack-file to the set if its "expected size" is
smaller than the batch size until the total expected size of the
selected pack-files is at least the batch size. The "expected
size" is calculated by taking the size of the pack-file divided
by the number of objects in the pack-file and multiplied by the
number of objects from the multi-pack-index with offset in that
pack-file. The expected size approximates how much data from that
pack-file will contribute to the resulting pack-file size. The
intention is that the resulting pack-file will be close in size
to the provided batch size.
The next run of the incremental-repack task will delete these
repacked pack-files during the 'expire' step.
In this version, the batch size is set to "0" which ignores the
size restrictions when selecting the pack-files. It instead
selects all pack-files and repacks all packed objects into a
single pack-file. This will be updated in the next change, but
it requires doing some calculations that are better isolated to
a separate change.
These steps are based on a similar background maintenance step in
Scalar (and VFS for Git) [1]. This was incredibly effective for
users of the Windows OS repository. After using the same VFS for Git
repository for over a year, some users had _thousands_ of pack-files
that combined to up to 250 GB of data. We noticed a few users were
running into the open file descriptor limits (due in part to a bug
in the multi-pack-index fixed by af96fe3 (midx: add packs to
packed_git linked list, 2019-04-29).
These pack-files were mostly small since they contained the commits
and trees that were pushed to the origin in a given hour. The GVFS
protocol includes a "prefetch" step that asks for pre-computed pack-
files containing commits and trees by timestamp. These pack-files
were grouped into "daily" pack-files once a day for up to 30 days.
If a user did not request prefetch packs for over 30 days, then they
would get the entire history of commits and trees in a new, large
pack-file. This led to a large number of pack-files that had poor
delta compression.
By running this pack-file maintenance step once per day, these repos
with thousands of packs spanning 200+ GB dropped to dozens of pack-
files spanning 30-50 GB. This was done all without removing objects
from the system and using a constant batch size of two gigabytes.
Once the work was done to reduce the pack-files to small sizes, the
batch size of two gigabytes means that not every run triggers a
repack operation, so the following run will not expire a pack-file.
This has kept these repos in a "clean" state.
[1] https://github.com/microsoft/scalar/blob/master/Scalar.Common/Maintenance/PackfileMaintenanceStep.cs
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that the multi-pack-index may be written as part of auto maintenance
at the end of a command, reduce the progress output when the operations
are quick. Use start_delayed_progress() instead of start_progress().
Update t5319-multi-pack-index.sh to use GIT_PROGRESS_DELAY=0 now that
the progress indicators are conditional.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The core.multiPackIndex setting has been around since c4d25228eb
(config: create core.multiPackIndex setting, 2018-07-12), but has been
disabled by default. If a user wishes to use the multi-pack-index
feature, then they must enable this config and run 'git multi-pack-index
write'.
The multi-pack-index feature is relatively stable now, so make the
config option true by default. For users that do not use a
multi-pack-index, the only extra cost will be a file lookup to see if a
multi-pack-index file exists (once per process, per object directory).
Also, this config option will be referenced by an upcoming
"incremental-repack" task in the maintenance builtin, so move the config
option into the repository settings struct. Note that if
GIT_TEST_MULTI_PACK_INDEX=1, then we want to ignore the config option
and treat core.multiPackIndex as enabled.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
As of recent Visual Studio versions, CMake support is built-in:
https://docs.microsoft.com/en-us/cpp/build/cmake-projects-in-visual-studio?view=vs-2019
All that needs to be done is to open the worktree as a folder, and
Visual Studio will find the `CMakeLists.txt` file and automatically
generate the project files.
Let's ignore the entirety of those generated files.
Helped-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We already match "committer", and we're about to start
matching more things. Let's use a more neutral variable to
avoid confusion.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
