Let's add a design doc about how we could improve handling liarge blobs
using "Large Object Promisors" (LOPs). It's a set of features with the
goal of using special dedicated promisor remotes to store large blobs,
and having them accessed directly by main remotes and clients.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A previous commit introduced a "promisor.acceptFromServer" configuration
variable with only "None" or "All" as valid values.
Let's introduce "KnownName" and "KnownUrl" as valid values for this
configuration option to give more choice to a client about which
promisor remotes it might accept among those that the server advertised.
In case of "KnownName", the client will accept promisor remotes which
are already configured on the client and have the same name as those
advertised by the client. This could be useful in a corporate setup
where servers and clients are trusted to not switch names and URLs, but
where some kind of control is still useful.
In case of "KnownUrl", the client will accept promisor remotes which
have both the same name and the same URL configured on the client as the
name and URL advertised by the server. This is the most secure option,
so it should be used if possible.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a server S knows that some objects from a repository are available
from a promisor remote X, S might want to suggest to a client C cloning
or fetching the repo from S that C may use X directly instead of S for
these objects.
Note that this could happen both in the case S itself doesn't have the
objects and borrows them from X, and in the case S has the objects but
knows that X is better connected to the world (e.g., it is in a
$LARGEINTERNETCOMPANY datacenter with petabit/s backbone connections)
than S. Implementation of the latter case, which would require S to
omit in its response the objects available on X, is left for future
improvement though.
Then C might or might not, want to get the objects from X. If S and C
can agree on C using X directly, S can then omit objects that can be
obtained from X when answering C's request.
To allow S and C to agree and let each other know about C using X or
not, let's introduce a new "promisor-remote" capability in the
protocol v2, as well as a few new configuration variables:
- "promisor.advertise" on the server side, and:
- "promisor.acceptFromServer" on the client side.
By default, or if "promisor.advertise" is set to 'false', a server S will
not advertise the "promisor-remote" capability.
If S doesn't advertise the "promisor-remote" capability, then a client C
replying to S shouldn't advertise the "promisor-remote" capability
either.
If "promisor.advertise" is set to 'true', S will advertise its promisor
remotes with a string like:
promisor-remote=<pr-info>[;<pr-info>]...
where each <pr-info> element contains information about a single
promisor remote in the form:
name=<pr-name>[,url=<pr-url>]
where <pr-name> is the urlencoded name of a promisor remote and
<pr-url> is the urlencoded URL of the promisor remote named <pr-name>.
For now, the URL is passed in addition to the name. In the future, it
might be possible to pass other information like a filter-spec that the
client may use when cloning from S, or a token that the client may use
when retrieving objects from X.
It is C's responsibility to arrange how it can reach X though, so pieces
of information that are usually outside Git's concern, like proxy
configuration, must not be distributed over this protocol.
It might also be possible in the future for "promisor.advertise" to have
other values. For example a value like "onlyName" could prevent S from
advertising URLs, which could help in case C should use a different URL
for X than the URL S is using. (The URL S is using might be an internal
one on the server side for example.)
By default or if "promisor.acceptFromServer" is set to "None", C will
not accept to use the promisor remotes that might have been advertised
by S. In this case, C will not advertise any "promisor-remote"
capability in its reply to S.
If "promisor.acceptFromServer" is set to "All" and S advertised some
promisor remotes, then on the contrary, C will accept to use all the
promisor remotes that S advertised and C will reply with a string like:
promisor-remote=<pr-name>[;<pr-name>]...
where the <pr-name> elements are the urlencoded names of all the
promisor remotes S advertised.
In a following commit, other values for "promisor.acceptFromServer" will
be implemented, so that C will be able to decide the promisor remotes it
accepts depending on the name and URL it received from S. So even if
that name and URL information is not used much right now, it will be
needed soon.
Helped-by: Taylor Blau <me@ttaylorr.com>
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git clone" learned to make a shallow clone for a single commit
that is not necessarily be at the tip of any branch.
* tc/clone-single-revision:
builtin/clone: teach git-clone(1) the --revision= option
parse-options: introduce die_for_incompatible_opt2()
clone: introduce struct clone_opts in builtin/clone.c
clone: add tags refspec earlier to fetch refspec
clone: refactor wanted_peer_refs()
clone: make it possible to specify --tags
clone: cut down on global variables in clone.c
All the documentation .txt files have been renamed to .adoc to help
content aware editors.
* bc/doc-adoc-not-txt:
Remove obsolete ".txt" extensions for AsciiDoc files
doc: use .adoc extension for AsciiDoc files
gitattributes: mark AsciiDoc files as LF-only
editorconfig: add .adoc extension
doc: update gitignore for .adoc extension
"git -c help.autocorrect=0 psuh" shows the suggested typofix,
unlike the previous attempt in the base topic.
* da/help-autocorrect-one-fix:
help: add "show" as a valid configuration value
help: show the suggested command when help.autocorrect is false
"[help] autocorrect = 1" used to be a way to say "please wait for
0.1 second after suggesting a typofix of the command name before
running that command"; now it means "yes, if there is a plausible
typofix for the command name, please run it immediately".
* sc/help-autocorrect-one:
help: interpret boolean string values for help.autocorrect
"git pack-objects" and its wrapper "git repack" learned an option
to use an alternative path-hash function to improve delta-base
selection to produce a packfile with deeper history than window
size.
* ds/name-hash-tweaks:
pack-objects: prevent name hash version change
test-tool: add helper for name-hash values
p5313: add size comparison test
pack-objects: add GIT_TEST_NAME_HASH_VERSION
repack: add --name-hash-version option
pack-objects: add --name-hash-version option
pack-objects: create new name-hash function version
In Git v2.44.0 support for 'git archive' over HTTP protocol
was added, but it was nowhere documented how it should be
enabled in git-http-backend.
Add missing documentation.
Signed-off-by: Piotr Szlazak <piotr.szlazak@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The git-clone(1) command has the option `--branch` that allows the user
to select the branch they want HEAD to point to. In a non-bare
repository this also checks out that branch.
Option `--branch` also accepts a tag. When a tag name is provided, the
commit this tag points to is checked out and HEAD is detached. Thus
`--branch` can be used to clone a repository and check out a ref kept
under `refs/heads` or `refs/tags`. But some other refs might be in use
as well. For example Git forges might use refs like `refs/pull/<id>` and
`refs/merge-requests/<id>` to track pull/merge requests. These refs
cannot be selected upon git-clone(1).
Add option `--revision` to git-clone(1). This option accepts a fully
qualified reference, or a hexadecimal commit ID. This enables the user
to clone and check out any revision they want. `--revision` can be used
in conjunction with `--depth` to do a minimal clone that only contains
the blob and tree for a single revision. This can be useful for
automated tests running in CI systems.
Using option `--branch` and `--single-branch` together is a similar
scenario, but serves a different purpose. Using these two options, a
singlet remote tracking branch is created and the fetch refspec is set
up so git-fetch(1) will receive updates on that branch from the remote.
This allows the user work on that single branch.
Option `--revision` on contrary detaches HEAD, creates no tracking
branches, and writes no fetch refspec.
Signed-off-by: Toon Claes <toon@iotcl.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
[jc: removed unnecessary TEST_PASSES_SANITIZE_LEAK from the test]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Option --no-tags was added in 0dab2468ee (clone: add a --no-tags option
to clone without tags, 2017-04-26). At the time there was no need to
support --tags as well, although there was some conversation about
it[1].
To simplify the code and to prepare for future commits, invert the flag
internally. Functionally there is no change, because the flag is
default-enabled passing `--tags` has no effect, so there's no need to
add tests for this.
[1]: https://lore.kernel.org/git/CAGZ79kbHuMpiavJ90kQLEL_AR0BEyArcZoEWAjPPhOFacN16YQ@mail.gmail.com/
Signed-off-by: Toon Claes <toon@iotcl.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a literal value for showing the suggested autocorrection
for consistency with the rest of the help.autocorrect options.
Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make the handling of false boolean values for help.autocorrect
consistent with the handling of value 0 by showing the suggested
commands but not running them.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Following the procedure we established to introduce breaking
changes for Git 3.0, allow an early opt-in for removing support of
$GIT_DIR/branches/ and $GIT_DIR/remotes/ directories to configure
remotes.
* ps/3.0-remote-deprecation:
remote: announce removal of "branches/" and "remotes/"
builtin/pack-redundant: remove subcommand with breaking changes
ci: repurpose "linux-gcc" job for deprecations
ci: merge linux-gcc-default into linux-gcc
Makefile: wire up build option for deprecated features
Doc and short-help text for "show-index" has been clarified to
stress that the command reads its data from the standard input.
* jc/show-index-h-update:
show-index: the short help should say the command reads from its input
Doc updates.
* ja/doc-commit-markup-updates:
doc: migrate git-commit manpage secondary files to new format
doc: convert git commit config to new format
doc: make more direct explanations in git commit options
doc: the mode param of -u of git commit is optional
doc: apply new documentation guidelines to git commit
Introduce a new API to visit objects in batches based on a common
path, or by type.
* ds/path-walk-1:
path-walk: drop redundant parse_tree() call
path-walk: reorder object visits
path-walk: mark trees and blobs as UNINTERESTING
path-walk: visit tags and cached objects
path-walk: allow consumer to specify object types
t6601: add helper for testing path-walk API
test-lib-functions: add test_cmp_sorted
path-walk: introduce an object walk by path
The new '--name-hash-version' option for 'git repack' is a simple
pass-through to the underlying 'git pack-objects' subcommand. However,
this subcommand may have other options and a temporary filename as part
of the subcommand execution that may not be predictable or could change
over time.
The existing test_subcommand method requires an exact list of arguments
for the subcommand. This is too rigid for our needs here, so create a
new method, test_subcommand_flex. Use it to check that the
--name-hash-version option is passing through.
Since we are modifying the 'git repack' command, let's bring its usage
in line with the Documentation's synopsis. This removes it from the
allow list in t0450 so it will remain in sync in the future.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous change introduced a new pack_name_hash_v2() function that
intends to satisfy much of the hash locality features of the existing
pack_name_hash() function while also distinguishing paths with similar
final components of their paths.
This change adds a new --name-hash-version option for 'git pack-objects'
to allow users to select their preferred function version. This use of
an integer version allows for future expansion and a direct way to later
store a name hash version in the .bitmap format.
For now, let's consider how effective this mechanism is when repacking a
repository with different name hash versions. Specifically, we will
execute 'git pack-objects' the same way a 'git repack -adf' process
would, except we include --name-hash-version=<n> for testing.
On the Git repository, we do not expect much difference. All path names
are short. This is backed by our results:
| Stage | Pack Size | Repack Time |
|-----------------------|-----------|-------------|
| After clone | 260 MB | N/A |
| --name-hash-version=1 | 127 MB | 129s |
| --name-hash-version=2 | 127 MB | 112s |
This example demonstrates how there is some natural overhead coming from
the cloned copy because the server is hosting many forks and has not
optimized for exactly this set of reachable objects. But the full repack
has similar characteristics for both versions.
Let's consider some repositories that are hitting too many collisions
with version 1. First, let's explore the kinds of paths that are
commonly causing these collisions:
* "/CHANGELOG.json" is 15 characters, and is created by the beachball
[1] tool. Only the final character of the parent directory can
differentiate different versions of this file, but also only the two
most-significant digits. If that character is a letter, then this is
always a collision. Similar issues occur with the similar
"/CHANGELOG.md" path, though there is more opportunity for
differences In the parent directory.
* Localization files frequently have common filenames but
differentiates via parent directories. In C#, the name
"/strings.resx.lcl" is used for these localization files and they
will all collide in name-hash.
[1] https://github.com/microsoft/beachball
I've come across many other examples where some internal tool uses a
common name across multiple directories and is causing Git to repack
poorly due to name-hash collisions.
One open-source example is the fluentui [2] repo, which uses beachball
to generate CHANGELOG.json and CHANGELOG.md files, and these files have
very poor delta characteristics when comparing against versions across
parent directories.
| Stage | Pack Size | Repack Time |
|-----------------------|-----------|-------------|
| After clone | 694 MB | N/A |
| --name-hash-version=1 | 438 MB | 728s |
| --name-hash-version=2 | 168 MB | 142s |
[2] https://github.com/microsoft/fluentui
In this example, we see significant gains in the compressed packfile
size as well as the time taken to compute the packfile.
Using a collection of repositories that use the beachball tool, I was
able to make similar comparisions with dramatic results. While the
fluentui repo is public, the others are private so cannot be shared for
reproduction. The results are so significant that I find it important to
share here:
| Repo | --name-hash-version=1 | --name-hash-version=2 |
|----------|-----------------------|-----------------------|
| fluentui | 440 MB | 161 MB |
| Repo B | 6,248 MB | 856 MB |
| Repo C | 37,278 MB | 6,755 MB |
| Repo D | 131,204 MB | 7,463 MB |
Future changes could include making --name-hash-version implied by a config
value or even implied by default during a full repack.
It is important to point out that the name hash value is stored in the
.bitmap file format, so we must force --name-hash-version=1 when bitmaps
are being read or written. Later, the bitmap format could be updated to
be aware of the name hash version so deltas can be quickly computed
across the bitmapped/not-bitmapped boundary. To promote the safety of
this parameter, the validate_name_hash_version() method will die() if
the given name-hash version is incorrect and will disable newer versions
if not yet compatible with other features, such as --write-bitmap-index.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit extends the functionality of `git gc`
by adding a new option, `--expire-to=<dir>`. Previously,
this feature was implemented in 91badeba32 (builtin/repack.c:
implement `--expire-to` for storing pruned objects, 2022-10-24),
which allowing users to specify a directory where unreachable
and expired cruft packs are stored during garbage collection.
However, users had to run `git repack --cruft --expire-to=<dir>`
followed by `git prune` to achieve similar results within `git gc`.
By introducing `--expire-to=<dir>` directly into `git gc`,
we simplify the process for users who wish to manage their
repository's cleanup more efficiently. This change involves
passing the `--expire-to=<dir>` parameter through to `git repack`,
making it easier for users to set up a backup location for cruft
packs that will be pruned.
Due to the original `git gc --prune=now` deleting all unreachable
objects by passing the `-a` parameter to git repack. With the
addition of the `--cruft` and `--expire-to` options, it is necessary
to modify this default behavior: instead of deleting these
unreachable objects, they should be merged into a cruft pack and
collected in a specified directory. Therefore, we do not pass `-a`
to the repack command but instead pass `--cruft`, `--expire-to`,
and `--cruft-expiration=now` to repack.
Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The trailer.* configuration variables are currently only described in
git-interpret-trailers(1) but affect git-commit and git-tag as well.
Move that section into its own config/trailer.txt file and also include
it in git-config(1).
Signed-off-by: Julian Prein <julian@druckdev.xyz>
Acked-by: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Back when Git was in its infancy, remotes were configured via separate
files in "branches/" (back in 2005). This mechanism was replaced later
that year with the "remotes/" directory. Both mechanisms have eventually
been replaced by config-based remotes, and it is very unlikely that
anybody still uses these directories to configure their remotes.
Both of these directories have been marked as deprecated, one in 2005
and the other one in 2011. Follow through with the deprecation and
finally announce the removal of these features in Git 3.0.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
[jc: with a small tweak to the help message]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Document that it is insecure to use Personal Access Tokens, which
some hosting providers take as username/password, embedded in URLs.
* mh/doc-credential-helpers-with-pat:
docs: discuss caching personal access tokens
docs: list popular credential helpers
The meson build procedure for Documentation/technical/ hierarchy was
missing necessary dependencies, which has been corrected.
* sj/meson-doc-technical-dependency-fix:
meson: fix missing deps for technical articles
Since we no longer have any AsciiDoc files that end in ".txt", don't
modify them with .gitattributes or ignore them with .gitignore.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We presently use the ".txt" extension for our AsciiDoc files. While not
wrong, most editors do not associate this extension with AsciiDoc,
meaning that contributors don't get automatic editor functionality that
could be useful, such as syntax highlighting and prose linting.
It is much more common to use the ".adoc" extension for AsciiDoc files,
since this helps editors automatically detect files and also allows
various forges to provide rich (HTML-like) rendering. Let's do that
here, renaming all of the files and updating the includes where
relevant. Adjust the various build scripts and makefiles to use the new
extension as well.
Note that this should not result in any user-visible changes to the
documentation.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We presently use the ".txt" extension for our AsciiDoc files. While not
wrong, most editors do not associate this extension with AsciiDoc,
meaning that contributors don't get automatic editor functionality that
could be useful, such as syntax highlighting and prose linting.
Instead, in a future commit, we're going to move to using the more
common ".adoc" extension for these files, which many editors
intrinsically recognize as an AsciiDoc file. To avoid contributors
accidentally checking in generated files, ignore the new extension for
generated files in the documentation .gitignore files.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We centrally explain that "--no-whatever" is the way to countermand
the "--whatever" option. Explain that a configured default and the
value specified by an environment variable can be overridden by the
corresponding command line option, too.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Acked-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Also prevent git-commit manpage to refer to itself in the config
description by using a variable.
Signed-off-by: Jean-Noël Avila <jn.avila@free.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
