Adapt the content from 'contrib/scalar/README.md' into a design document in
'Documentation/technical/'. In addition to reformatting for asciidoc,
elaborate on the background, purpose, and design choices that went into
Scalar.
Most of this document will persist in the 'Documentation/technical/' after
Scalar has been moved out of 'contrib/' and into the root of Git. Until that
time, it will also contain a temporary "Roadmap" section detailing the
remaining series needed to finish the initial version of Scalar. The section
will be removed once Scalar is moved to the repo root, but in the meantime
serves as a guide for readers to keep up with progress on the feature.
Signed-off-by: Victoria Dye <vdye@github.com>
Acked-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rephrase documentation to describe scalar as a "large repo management tool"
rather than an "opinionated management tool". The new description is
intended to more directly reflect the utility of scalar to better guide
users in preparation for scalar being built and installed as part of Git.
Signed-off-by: Victoria Dye <vdye@github.com>
Acked-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a coccinelle rule to remove "struct strbuf" initialization
followed by calling "strbuf_release()" function, without any uses of
the strbuf in the same function.
See the tests in contrib/coccinelle/tests/unused.{c,res} for what it's
intended to find and replace.
The inclusion of "contrib/scalar/scalar.c" is because "spatch" was
manually run on it (we don't usually run spatch on contrib).
Per the "buggy code" comment we also match a strbuf_init() before the
xmalloc(), but we're not seeking to be so strict as to make checks
that the compiler will catch for us redundant. Saying we'll match
either "init" or "xmalloc" lines makes the rule simpler.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When operating at the scale that Scalar wants to support, certain data
shapes are more likely to cause undesirable performance issues, such as
large numbers of loose objects.
By including statistics about this, `scalar diagnose` now makes it
easier to identify such scenarios.
Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It's helpful to see if there are other crud files in the pack
directory. Let's teach the `scalar diagnose` command to gather
file size information about pack files.
While at it, also enumerate the pack files in the alternate
object directories, if any are registered.
Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When analyzing problems with large worktrees/repositories, it is useful
to know how close to a "full disk" situation Scalar/Git operates. Let's
include this information.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Over the course of Scalar's development, it became obvious that there is
a need for a command that can gather all kinds of useful information
that can help identify the most typical problems with large
worktrees/repositories.
The `diagnose` command is the culmination of this hard-won knowledge: it
gathers the installed hooks, the config, a couple statistics describing
the data shape, among other pieces of information, and then wraps
everything up in a tidy, neat `.zip` archive.
Note: originally, Scalar was implemented in C# using the .NET API, where
we had the luxury of a comprehensive standard library that includes
basic functionality such as writing a `.zip` file. In the C version, we
lack such a commodity. Rather than introducing a dependency on, say,
libzip, we slightly abuse Git's `archive` machinery: we write out a
`.zip` of the empty try, augmented by a couple files that are added via
the `--add-file*` options. We are careful trying not to modify the
current repository in any way lest the very circumstances that required
`scalar diagnose` to be run are changed by the `diagnose` run itself.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `scalar` command needs a Scalar enlistment for many subcommands, and
looks in the current directory for such an enlistment (traversing the
parent directories until it finds one).
These is subcommands can also be called with an optional argument
specifying the enlistment. Here, too, we traverse parent directories as
needed, until we find an enlistment.
However, if the specified directory does not even exist, or is not a
directory, we should stop right there, with an error message.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A micro fix to a topic earlier merged to 'master'
source: <patch-1.1-05949221e3f-20220319T002715Z-avarab@gmail.com>
* ab/make-optim-noop:
contrib/scalar: fix 'all' target in Makefile
Documentation/Makefile: fix "make info" regression in dad9cd7d51
Add extra ':' to second 'all' target definition to allow 'scalar' to build.
Without this fix, the 'all:' and 'all::' targets together cause a build
failure when 'scalar' build is enabled with 'INCLUDE_SCALAR':
Makefile:14: *** target file `all' has both : and :: entries. Stop.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git stash" does not allow subcommands it internally runs as its
implementation detail, except for "git reset", to emit messages;
now "git reset" part has also been squelched.
* vd/stash-silence-reset:
reset: show --no-refresh in the short-help
reset: remove 'reset.refresh' config option
reset: remove 'reset.quiet' config option
reset: do not make '--quiet' disable index refresh
stash: make internal resets quiet and refresh index
reset: suppress '--no-refresh' advice if logging is silenced
reset: replace '--quiet' with '--no-refresh' in performance advice
reset: introduce --[no-]refresh option to --mixed
reset: revise index refresh advice
Remove the 'reset.quiet' config option, remove '--no-quiet' documentation in
'Documentation/git-reset.txt'. In 4c3abd0551 (reset: add new reset.quiet
config setting, 2018-10-23), 'reset.quiet' was introduced as a way to
globally change the default behavior of 'git reset --mixed' to skip index
refresh.
However, now that '--quiet' does not affect index refresh, 'reset.quiet'
would only serve to globally silence logging. This was not the original
intention of the config setting, and there's no precedent for such a setting
in other commands with a '--quiet' option, so it appears to be obsolete.
In addition to the options & its documentation, remove 'reset.quiet' from
the recommended config for 'scalar'.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The $(QUIET) variables we define are largely duplicated between our
various Makefiles, let's define them in the new "shared.mak" instead.
Since we're not using the environment to pass these around we don't
need to export the "QUIET_GEN" and "QUIET_BUILT_IN" variables
anymore. The "QUIET_GEN" variable is used in "git-gui/Makefile" and
"gitweb/Makefile", but they've got their own definition for those. The
"QUIET_BUILT_IN" variable is only used in the top-level "Makefile". We
still need to export the "V" variable.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We have various behavior that's shared across our Makefiles, or that
really should be (e.g. via defined templates). Let's create a
top-level "shared.mak" to house those sorts of things, and start by
adding the ".DELETE_ON_ERROR" flag to it.
See my own 7b76d6bf22 (Makefile: add and use the ".DELETE_ON_ERROR"
flag, 2021-06-29) and db10fc6c09 (doc: simplify Makefile using
.DELETE_ON_ERROR, 2021-05-21) for the addition and use of the
".DELETE_ON_ERROR" flag.
I.e. this changes the behavior of existing rules in the altered
Makefiles (except "Makefile" & "Documentation/Makefile"). I'm
confident that this is safe having read the relevant rules in those
Makfiles, and as the GNU make manual notes that it isn't the default
behavior is out of an abundance of backwards compatibility
caution. From edition 0.75 of its manual, covering GNU make 4.3:
[Enabling '.DELETE_ON_ERROR' is] almost always what you want
'make' to do, but it is not historical practice; so for
compatibility, you must explicitly request it.
This doesn't introduce a bug by e.g. having this
".DELETE_ON_ERROR" flag only apply to this new shared.mak, Makefiles
have no such scoping semantics.
It does increase the danger that any Makefile without an explicit "The
default target of this Makefile is..." snippet to define the default
target as "all" could have its default rule changed if our new
shared.mak ever defines a "real" rule. In subsequent commits we'll be
careful not to do that, and such breakage would be obvious e.g. in the
case of "make -C t".
We might want to make that less fragile still (e.g. by using
".DEFAULT_GOAL" as noted in the preceding commit), but for now let's
simply include "shared.mak" without adding that boilerplate to all the
Makefiles that don't have it already. Most of those are already
exposed to that potential caveat e.g. due to including "config.mak*".
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make the "contrib/scalar/Makefile" be stylistically consistent with
the top-level "Makefile" in first declaring "all" to be the default
rule, followed by including other Makefile snippets.
This adjusts code added in 0a43fb2202 (scalar: create a rudimentary
executable, 2021-12-03), it further ensures that when we add another
"include" file in a subsequent commit that the included file won't be
the one to define our default target.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `git` executable has these two very useful options:
-C <directory>:
switch to the specified directory before performing any actions
-c <key>=<value>:
temporarily configure this setting for the duration of the
specified scalar subcommand
With this commit, we teach the `scalar` executable the same trick.
Note: It might look like a good idea to try to reuse the
`handle_options()` function in `git.c` instead of replicating only the
`-c`/`-C` part. However, that function is not only not in `libgit.a`, it
is also intricately entangled with the rest of the code in `git.c` that
is necessary e.g. to handle `--paginate`. Besides, no other option
handled by that `handle_options()` function is relevant to Scalar,
therefore the cost of refactoring vastly would outweigh the benefit.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The .NET version of Scalar has a `version` command. This was necessary
because it was versioned independently of Git.
Since Scalar is now tightly coupled with Git, it does not make sense for
them to show different versions. Therefore, it shows the same output as
`git version`. For backwards-compatibility with the .NET version,
`scalar version` prints to `stderr`, though (`git version` prints to
`stdout` instead).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Delete an enlistment by first unregistering the repository and then
deleting the enlistment directory (usually the directory containing the
worktree `src/` directory).
On Windows, if the current directory is inside the enlistment's
directory, change to the parent of the enlistment directory, to allow us
to delete the enlistment (directories used by processes e.g. as current
working directories cannot be deleted on Windows).
Co-authored-by: Victoria Dye <vdye@github.com>
Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
After a Scalar upgrade, it can come in really handy if there is an easy
way to reconfigure all Scalar enlistments. This new option offers this
functionality.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This comes in handy during Scalar upgrades, or when config settings were
messed up by mistake.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Note: this subcommand is provided primarily for backwards-compatibility,
for existing Scalar uses. It is mostly just a shim for `git
maintenance`, mapping task names from the way Scalar called them to the
way Git calls them.
The reason why those names differ? The background maintenance was first
implemented in Scalar, and when it was contributed as a patch series
implementing the `git maintenance` command, reviewers suggested better
names, those suggestions were accepted before the patches were
integrated into core Git.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Just like `git clone`, the `scalar clone` command now also offers to
restrict the clone to a single branch.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This implements Scalar's opinionated `clone` command: it tries to use a
partial clone and sets up a sparse checkout by default. In contrast to
`git clone`, `scalar clone` sets up the worktree in the `src/`
subdirectory, to encourage a separation between the source files and the
build output (which helps Git tremendously because it avoids untracked
files that have to be specifically ignored when refreshing the index).
Also, it registers the repository for regular, scheduled maintenance,
and configures a flurry of configuration settings based on the
experience and experiments of the Microsoft Windows and the Microsoft
Office development teams.
Note: since the `scalar clone` command is by far the most commonly
called `scalar` subcommand, we document it at the top of the manual
page.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The produced list simply consists of those repositories registered under
the multi-valued `scalar.repo` config setting in the user's Git config.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a user deleted an enlistment manually, let's be generous and
_still_ unregister it.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Just like `scalar register` starts the scheduled background maintenance,
`scalar unregister` stops it. Note that we use `git maintenance start`
in `scalar register`, but we do not use `git maintenance stop` in
`scalar unregister`: this would stop maintenance for _all_ repositories,
not just for the one we want to unregister.
The `unregister` command also removes the corresponding entry from the
`[scalar]` section in the global Git config.
Co-authored-by: Victoria Dye <vdye@github.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Let's start implementing the `register` command. With this commit,
recommended settings are configured upon `scalar register`, and Git's
background maintenance is started.
The recommended config settings may very well change in the future. For
example, once the built-in FSMonitor is available, we will want to
enable it upon `scalar register`. For that reason, we explicitly support
running `scalar register` in an already-registered enlistment.
Co-authored-by: Victoria Dye <vdye@github.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To test the Scalar command, create a test script in contrib/scalar/t
that is executed as `make -C contrib/scalar test`. Since Scalar has no
meaningful capabilities yet, the only test is rather simple. We will add
more tests in subsequent commits that introduce corresponding, new
functionality.
Note: This test script is intended to test `scalar` only lightly, even
after all of the functionality is implemented.
A more comprehensive functional (or: integration) test suite can be
found at https://github.com/microsoft/scalar; It is used in the workflow
https://github.com/microsoft/git/blob/HEAD/.github/workflows/scalar-functional-tests.yml
in Microsoft's Git fork. This test suite performs end-to-end tests with
a real remote repository, and is run as part of the regular CI and PR
builds in that fork.
Since those tests require some functionality supported only by
Microsoft's Git fork ("GVFS protocol"), there is no intention to port
that fuller test suite to `contrib/scalar/`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Let's build up the documentation for the Scalar command along with the
patches that implement its functionality.
Note: To discourage the feature-incomplete documentation from being
mistaken for the complete thing, we do not yet provide any way to build
HTML or manual pages from the text file.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The idea of Scalar (https://github.com/microsoft/scalar), and before
that, of VFS for Git, has always been to prove that Git _can_ scale, and
to upstream whatever strategies have been demonstrated to help.
With this patch, we start the journey from that C# project to move what
is left to Git's own `contrib/` directory, reimplementing it in pure C,
with the intention to facilitate integrating the functionality into core
Git all while maintaining backwards-compatibility for existing Scalar
users (which will be much easier when both live in the same worktree).
It has always been the plan to contribute all of the proven strategies
back to core Git.
For example, while the virtual filesystem provided by VFS for Git helped
the team developing the Windows operating system to move onto Git, while
trying to upstream it we realized that it cannot be done: getting the
virtual filesystem to work (which we only managed to implement fully on
Windows, but not on, say, macOS or Linux), and the required server-side
support for the GVFS protocol, made this not quite feasible.
The Scalar project learned from that and tackled the problem with
different tactics: instead of pretending to Git that the working
directory is fully populated, it _specifically_ teaches Git about
partial clone (which is based on VFS for Git's cache server), about
sparse checkout (which VFS for Git tried to do transparently, in the
file system layer), and regularly runs maintenance tasks to keep the
repository in a healthy state.
With partial clone, sparse checkout and `git maintenance` having been
upstreamed, there is little left that `scalar.exe` does which `git.exe`
cannot do. One such thing is that `scalar clone <url>` will
automatically set up a partial, sparse clone, and configure
known-helpful settings from the start.
So let's bring this convenience into Git's tree.
The idea here is that you can (optionally) build Scalar via
make -C contrib/scalar/
This will build the `scalar` executable and put it into the
contrib/scalar/ subdirectory.
The slightly awkward addition of the `contrib/scalar/*` bits to the
top-level `Makefile` are actually really required: we want to link to
`libgit.a`, which means that we will need to use the very same `CFLAGS`
and `LDFLAGS` as the rest of Git.
An early development version of this patch tried to replicate all the
conditional code in `contrib/scalar/Makefile` (e.g. `NO_POLL`) just like
`contrib/svn-fe/Makefile` used to do before it was retired. It turned
out to be quite the whack-a-mole game: the SHA-1-related flags, the
flags enabling/disabling `compat/poll/`, `compat/regex/`,
`compat/win32mmap.c` & friends depending on the current platform... To
put it mildly: it was a major mess.
Instead, this patch makes minimal changes to the top-level `Makefile` so
that the bits in `contrib/scalar/` can be compiled and linked, and
adds a `contrib/scalar/Makefile` that uses the top-level `Makefile` in a
most minimal way to do the actual compiling.
Note: With this commit, we only establish the infrastructure, no
Scalar functionality is implemented yet; We will do that incrementally
over the next few commits.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The Scalar command will be contributed incrementally, over a bunch of
patch series. Let's document what Scalar is about, and then describe the
patch series that are planned.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
