When we fetch from a configured remote, we may try to update the local
refs/remotes/<origin>/HEAD, and so we ask the server to advertise its
HEAD to us.
But if we aren't otherwise asking about any refs at all, then we know
this HEAD update can never happen! To consider a new value for HEAD,
the set_head() function uses guess_remote_head(). And even if it sees an
explicit symref value for HEAD, it will only report that as a match if
we also saw that remote ref advertised, and it mapped to a local
tracking ref via get_fetch_map().
In other words, a fetch like this:
git fetch origin $exact_oid:refs/heads/foo
can never update HEAD, because we will never have fetched (nor even see
the advertisement for) the ref that HEAD points to.
Currently the command above will still call ls-refs to ask about the
HEAD, even though it is pointless. This patch teaches it to skip the
ls-refs call entirely in this case, which avoids a round-trip to the
server.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When using the ref-prefix feature of protocol v2, a client which sends
no prefixes at all will get the full advertisement. And so the code in
git-fetch was historically loose about setting up that list based on our
refspecs. There were cases where we needed to know about some refs, so
we just didn't add anything to the ref-prefix list.
And hence further code, like that for tag-following and updating
origin/HEAD, had to be careful about adding to an empty list. E.g., see
the bug fixed by bd52d9a058 (fetch: fix following tags when fetching
specific OID, 2025-03-07).
But the previous commit removed the last such case, and now we know an
empty ref-prefix list (at least inside git-fetch's do_fetch() function)
means that we really don't need to see any refs. So we can drop those
extra conditionals.
This simplifies the code a little. But it also means that some cases can
now use ref prefixes when they would not otherwise. As the test shows,
fetching an exact oid into a local ref can now avoid enumerating all of
the refs. The refspec itself doesn't need to know about any remote refs,
and the tag auto-following can just ask about refs/tags/.
The same is true for asking about HEAD to update the local origin/HEAD.
I didn't add a test for that yet, though, as we can optimize it even
further.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If we're not given any refspecs (either on the command line or via
config) and we have no branch merge config, then we fetch the remote
HEAD into our local FETCH_HEAD. In that case we do not send any
ref-prefix option to the server at all, and we see the full
advertisement.
But this is sub-optimal. We only care about HEAD, so we can just ask
for that, and ignore all of the other refs.
The new test demonstrates a case where we see fewer refs (in this case
only one less, but in theory we could be ignoring millions of them).
This also removes the only case where we care about seeing some refs
from the other side, but don't add anything to the ref_prefixes list.
Cleaning this up means one less maintenance burden. Before this patch,
any code which wanted to add to the list had to make sure the list was
not empty, since an empty list meant "ask for everything". Now it really
means "we are not interested in any refs".
This should let us optimize a few more cases in subsequent patches.
Note that we'll add "HEAD" to the list of prefixes, and later code for
updating "refs/remotes/<remote>/HEAD" may likewise do so. In theory this
could cause duplicates in the list, but in practice these can't both
trigger. We hit our new case only if there are no refspecs, and the
"<remote>/HEAD" feature is enabled only when we are fetching from a
remote with configured refspecs. We could be defensive with a flag, but
it didn't seem worth it to me (the absolute worse case is a useless
redundant ref-prefix line sent to the server).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The point of refspec_ref_prefixes() is to look over the set of refspecs
and set up an appropriate list of "ref-prefix" strings to send to the
server.
The logic for handling individual refspec_items has some confusing bits.
The final part of our if/else cascade checks this:
else if (item->src && !item->exact_sha1)
prefix = item->src;
But we know that "item->exact_sha1" can never be true, because earlier
we did:
if (item->exact_sha1 || item->negative)
continue;
This is due to 6c301adb0a (fetch: do not pass ref-prefixes for fetch by
exact SHA1, 2018-05-31), which added the continue. So it is tempting to
remove the extra exact_sha1 at the end of the cascade, leaving the one
at the top of the loop.
But I don't think that's quite right. The full cascade is:
if (rs->fetch == REFSPEC_FETCH)
prefix = item->src;
else if (item->dst)
prefix = item->dst;
else if (item->src && !item->exact_sha1)
prefix = item->src;
which all comes from 6373cb598e (refspec: consolidate ref-prefix
generation logic, 2018-05-16). That first "if" is supposed to handle
fetches, where we care about the source name, since that is coming from
the server. And the rest should be for pushes, where we care about the
destination, since that's the name the server will use. And we get that
either explicitly from "dst" (for something like "foo:bar") or
implicitly from the source (a refspec like "foo" is treated as
"foo:foo").
But how should exact_sha1 interact with those? For a fetch, exact_sha1
always means we do not care about sending a name to the server (there is
no server refname at all). But pushing an exact sha1 should still care
about the destination on the server! It is only if we have to fall back
to the implicit source that we need to care if it is a real ref (though
arguably such a push does not even make sense; where would the server
store it?).
So I think that 6c301adb0a "broke" the push case by always skipping
exact_sha1 items, even though a push should only care about the
destination.
Of course this is all completely academic. We have still not implemented
a v2 push protocol, so even though we do call this function for pushes,
we'd never actually send these ref-prefix lines.
However, given the effort I spent to figure out what was going on here,
and the overlapping exact_sha1 checks, I'd like to rewrite this to
preemptively fix the bug, and hopefully make it less confusing.
This splits the "if" at the top-level into fetch vs push, and then each
handles exact_sha1 appropriately itself. The check for negative refspecs
remains outside of either (there is no protocol support for them, so we
never send them to the server, but rather use them only to reduce the
advertisement we receive).
The resulting behavior should be identical for fetches, but hopefully
sets us up better for a potential future v2 push.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 6c301adb0a (fetch: do not pass ref-prefixes for fetch by exact
SHA1, 2018-05-31) added a test that fetching an exact oid with the v2
protocol works. Originally it failed without the code change from that
commit, because fetch failed with "no matching remote head".
That changed in 0177565148 (transport: do not list refs if possible,
2018-09-27), which made fetch more forgiving of this case.
But that now meant the test passes even without its fix! So let's also
have it check the packet listing to make sure we did not ask for the
bogus prefix (ultimately this is less important than whether the command
fails, since it's just an optimization, but we should make sure not to
regress it).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When this test was added in 6c301adb0a (fetch: do not pass ref-prefixes
for fetch by exact SHA1, 2018-05-31), there was still some uncertainty
about the v2 protocol's looser behavior with serving objects that are
not directly pointed at by a ref.
At this point that behavior is well established, and I do not think we
would ever change v2 to match the v0 behavior (and if we did,
remembering to update this test is the least of our concerns).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
These old tests refer to object ids as "sha1". These days we prefer
the more algorithm-agnostic "oid".
There are a few more tests that mention sha1 in the title and also use
it in variables throughout the test. I've left them for now, as changing
them is more involved (and they're linked to the allowTipSHA1InWant
config, which as a v0-only thing actually is always sha1).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 3f763ddf28 (fetch: set remote/HEAD if it does not exist, 2024-11-22),
unconditionally adds "HEAD" to the list of ref prefixes we send to the
server.
This breaks a core assumption that the list of prefixes we send to the
server is complete. We must either send all prefixes we care about, or
none at all (in the latter case the server then advertises everything).
The tag following code is careful to only add "refs/tags/" to the list
of prefixes if there are already entries in the prefix list. But because
the new code from 3f763ddf28 runs after the tag code, and because it
unconditionally adds to the prefix list, we may end up with a prefix
list that _should_ have "refs/tags/" in it, but doesn't.
When that is the case, the server does not advertise any tags, and our
auto-following breaks because we never learned about any tags in the
first place.
Fix this by only adding "HEAD" to the ref prefixes when we know that we
are already limiting the advertisement. In either case we'll learn about
HEAD (either through the limited advertisement, or implicitly through a
full advertisement).
Reported-by: Igor Todorovski <itodorov@ca.ibm.com>
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Hotfix to help building Git-for-Windows.
* js/win-2.49-build-fixes:
cmake: generalize the handling of the `CLAR_TEST_OBJS` list
meson: fix sorting
ident: stop assuming that `gw_gecos` is writable
Some future breaking changes would remove certain parts of the
default repository, which were still described even when the
documents were built for the future with WITH_BREAKING_CHANGES.
* pw/repo-layout-doc-update:
docs: fix repository-layout when building with breaking changes
A late-comer to the v2.49.0 party, `sk/unit-test-oid`, added yet another
array item to `CLAR_TEST_OBJS`, causing the `win+VS build` job to fail
with symptoms like this one:
unit-tests-lib.lib(u-oid-array.obj) : error LNK2019: unresolved
external symbol cl_parse_any_oid referenced in function fill_array
This is a similar scenario to the one that forced me to write
8afda42fce (cmake: generalize the handling of the `UNIT_TEST_OBJS`
list, 2024-09-18): The hard-coded echo of `CLAR_TEST_OBJS` in
`CMakeLists.txt` that recapitulates faithfully what was already
hard-coded in `Makefile` would either have to be updated whack-a-mole
style, or generalized.
Just like I chose the latter option for `UNIT_TEST_OBJS`, I now do the
same for `CLAR_TEST_OBJS`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 904339edbd (Introduce support for the Meson build system,
2024-12-06) the `meson.build` file was introduced, adding also a
Windows-specific list of source files. This list was obviously meant to
be sorted alphabetically, but there is one mistake. Let's fix that.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 590e081dea (ident: add NO_GECOS_IN_PWENT for systems without
pw_gecos in struct passwd, 2011-05-19), code was introduced to iterate
over the `gw_gecos` field; The loop variable is of type `char *`, which
assumes that `gw_gecos` is writable.
However, it is not necessarily writable (and it is a bad idea to have it
writable in the first place), so let's switch the loop variable type to
`const char *`.
This is not a new problem, but what is new is the Meson build. While it
does not trigger in CI builds, imitating the commands of
`ci/run-build-and-tests.sh` in a regular Git for Windows SDK (`meson
setup build . --fatal-meson-warnings --warnlevel 2 --werror --wrap-mode
nofallback -Dfuzzers=true` followed by `meson compile -C build --`
results in this beautiful error:
"cc" [...] -o libgit.a.p/ident.c.obj "-c" ../ident.c
../ident.c: In function 'copy_gecos':
../ident.c:68:18: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
68 | for (src = get_gecos(w); *src && *src != ','; src++) {
| ^
cc1.exe: all warnings being treated as errors
Now, why does this not trigger in CI? The answer is as simple as it is
puzzling: The `win+Meson` job completely side-steps Git for Windows'
development environment, opting instead to use the GCC that is on the
`PATH` in GitHub-hosted `windows-latest` runners. That GCC is pinned to
v12.2.0 and targets the UCRT (unlikely to change any time soon, see
https://github.com/actions/runner-images/blob/win25/20250303.1/images/windows/toolsets/toolset-2022.json#L132-L141).
That is in stark contrast to Git for Windows, which uses GCC v14.2.0 and
targets MSVCRT. Git for Windows' `Makefile`-based build also obviously
uses different compiler flags, otherwise this compile error would have
had plenty of opportunity in almost 14 years to surface.
In other words, contrary to my expectations, the `win+Meson` job is
ill-equipped to replace the `win build` job because it exercises a
completely different tool version/compiler flags vector than what Git
for Windows needs.
Nevertheless, there is currently this huge push, including breaking
changes after -rc1 and all, for switching to Meson. Therefore, we need
to make it work, somehow, even in Git for Windows' SDK, hence this
patch, at this point in time.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Meson-based build procedure forgot to build some docs, which has
been corrected.
* pw/build-meson-technical-and-howto-docs:
meson: fix building technical and howto docs
The editorconfig file is updated to tell us that bash scripts are
similar to general Bourne shell scripts.
* dm/editorconfig-bash-is-like-sh:
editorconfig: add .bash extension
Convert a few unit tests to the clar framework.
* sk/unit-test-oid:
t/unit-tests: convert oidtree test to use clar test framework
t/unit-tests: convert oidmap test to use clar test framework
t/unit-tests: convert oid-array test to use clar test framework
t/unit-tests: implement clar specific oid helper functions
The path.[ch] API takes an explicit repository parameter passed
throughout the callchain, instead of relying on the_repository
singleton instance.
* ps/path-sans-the-repository:
path: adjust last remaining users of `the_repository`
environment: move access to "core.sharedRepository" into repo settings
environment: move access to "core.hooksPath" into repo settings
repo-settings: introduce function to clear struct
path: drop `git_path()` in favor of `repo_git_path()`
rerere: let `rerere_path()` write paths into a caller-provided buffer
path: drop `git_common_path()` in favor of `repo_common_path()`
worktree: return allocated string from `get_worktree_git_dir()`
path: drop `git_path_buf()` in favor of `repo_git_path_replace()`
path: drop `git_pathdup()` in favor of `repo_git_path()`
path: drop unused `strbuf_git_path()` function
path: refactor `repo_submodule_path()` family of functions
submodule: refactor `submodule_to_gitdir()` to accept a repo
path: refactor `repo_worktree_path()` family of functions
path: refactor `repo_git_path()` family of functions
path: refactor `repo_common_path()` family of functions
Since commit 8ccc75c245 (remote: announce removal of "branches/" and
"remotes/", 2025-01-22) enabling WITH_BREAKING_CHANGES when building git
removes support for reading branches from ".git/branches" and remotes
from ".git/remotes". However those locations are still documented in
gitrepository-layout.adoc even though the build does not support them.
Rectify this by adding a new document attribute "with-breaking-changes"
and use it to make the inclusion of those sections of the documentation
conditional. Note that the name of the attribute does not match the test
prerequisite WITHOUT_BREAKING_CHANGES added in c5bc9a7f94 (Makefile:
wire up build option for deprecated features, 2025-01-22). This is to
avoid the awkward double negative ifndef::without_breaking_changes for
documentation that should be included when WITH_BREAKING_CHANGES is
enabled. The test prerequisite will be renamed to match the
documentation attribute in a future patch series.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If block_source_read_block() or parse_footer() fail, we leak the "name"
member of struct reftable_reader in reftable_reader_new(). Release it.
Reported by: H Z <shiyuyuranzh@gmail.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jeff King