Forcing a branch to a commit that no ref points at aborts when both
`submodule.recurse` and `submodule.propagateBranches` are set and
the repository has a remote configured:
BUG: refspec.c:442: refspec_find_match: need either src or dst
Aborted (core dumped)
`create_branches_recursively()` resolves the start point through
`dwim_branch_start()`, which leaves `branch_point` NULL when the
start point names no ref -- an object id, or a revision expression
such as `HEAD~0`. That NULL becomes `tracking_name`, and the
`setup_tracking()` call below it is guarded on `track` alone.
`setup_tracking()` assigns it to `tracking.spec.dst` without
checking, then hands the spec to `for_each_remote()`, so
`refspec_find_match()` receives a query with neither src nor dst
and trips its assertion.
`for_each_remote()` never reaches that callback where no remote is
configured, which is why the abort needs one.
961b130d20 (branch: add --recurse-submodules option for branch
creation, 2022-01-28) added the call with no guard at all.
75388bf5b4 (branch: support more tracking modes when recursing,
2022-03-29) added the guard on `track`.
Updating the branch happens before the abort, so the command does
what was asked and then exits 134.
Callers that check the exit status therefore see a failure that did
not happen, and one that rolls back on failure would undo a
successful update.
`create_branch()` already declines this: it calls `setup_tracking()`
under `if (real_ref && track)`, leaving tracking unset when the
start point resolved to no ref.
Make the recursive path agree.
Checking for NULL inside `setup_tracking()` would also silence the
abort, but it would put the decision in the callee for one caller
that has the answer already, and leave the two creation paths
disagreeing about when tracking is set up.
Reproducing it needs all four of:
- `submodule.recurse=true`
- `submodule.propagateBranches=true`
- a configured remote
- a start point that is not a ref name
Submodules take no part, so the new test builds a repository with
neither a submodule nor a `.gitmodules`, where `propagateBranches`
is set and has nothing to propagate to.
Assisted-by: An LLM.
Signed-off-by: Volodymyr Vriukalo <0@zitro.id>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation for 'git interpret-trailers' has been updated to explain
the format of trailer keys (alphanumeric characters and hyphens),
replace outdated terminology, define key terms upfront, and document
how comment lines in the input are treated.
* kh/doc-trailers:
doc: interpret-trailers: document comment line treatment
doc: interpret-trailers: rewrite new-trailers paragraphs
doc: interpret-trailers: commit to “trailer block” term
doc: interpret-trailers: join new-trailers again
doc: interpret-trailers: add key format example
doc: interpret-trailers: explain key format
doc: interpret-trailers: explain the format after the intro
doc: interpret-trailers: not just for commit messages
doc: interpret-trailers: use “metadata” in Name as well
doc: interpret-trailers: replace “lines” with “metadata”
doc: interpret-trailers: stop fixating on RFC 822
The creation of the on-disk data structures for the object database
has been made pluggable, allowing future backends to customize their
setup. As part of this, the initialization of the object database
has been deferred, and the loading of the loose-object map has been
detangled from repository initialization.
* ps/odb-make-creation-pluggable:
odb: make creation of on-disk structures pluggable
odb/source: introduce function to map source type to name
setup: defer object database creation
setup: handle ODB-related environment variables in `odb_new()`
setup: detangle loading of loose object maps
loose: load loose object map for the correct source
The 'git branch' command has been taught the '--delete-merged' option
to remove local branches that are already merged into their tracked
remote-tracking branches.
* hn/branch-delete-merged:
branch: add --dry-run for --delete-merged
branch: add branch.<name>.deleteMerged opt-out
branch: add --delete-merged <pattern>
branch: prepare delete_branches for a bulk caller
branch: let delete_branches skip unmerged branches on bulk refusal
branch: convert delete_branches() to a flags argument
branch: add --forked filter for --list mode
The 'git bisect' command has been taught a
'--reset-when-found[=<where>]' option that tells the command to
automatically run 'git bisect reset' to jump back to the original
state or to the found culprit.
* hn/bisect-reset-when-found:
bisect: add --reset-when-found to leave when done
bisect: let bisect_reset() optionally check out quietly
A compatibility wrapper for writev(3p) has been reintroduced,
including fixes for CMake build and 'MAX_IO_SIZE' limits on NonStop.
Calls to write(3p) in send_sideband() and cat_blob() have been
refactored to use writev(3p) wrappers to reduce syscall overhead.
* ps/writev:
fast-import: use writev(3p) to send cat-blob responses
sideband: use writev(3p) to send pktlines
wrapper: properly handle MAX_IO_SIZE in writev(3p)
wrapper: introduce writev(3p) wrappers
compat/posix: introduce writev(3p) wrapper
The known limitations of the ref format migration in 'git refs' have
been moved to be displayed as a warning admonition directly under the
description of the 'migrate' subcommand, improving visibility. A
reference to 'git-maintenance' has also been corrected to use the
'linkgit' macro.
* kh/doc-refs-migrate-limitations:
doc: refs: linkgit to git-maintenance(1)
doc: refs: put ref migration warning under the command
'git add' has been taught a new '--resolved' option to stage
conflict-resolved paths, while leaving unrelated local changes
unstaged. It scans the unmerged paths for leftover conflict
markers and aborts if any are found.
* jc/add-resolved:
add: introduce '--resolved' option
read-cache: add remove_file_from_index_with_flags()
merge-ll: consolidate conflict marker scanning logic
read-cache: reindent
The 'ssh-agent' tests in 't7528' have been fixed to work when the
user's login shell is csh-like, by explicitly passing '-s' to
'ssh-agent' to force Bourne shell syntax.
* kl/t7528-ssh-agent-for-csh-users:
t7528: fix failure under csh
Concurrent downloads of packfiles via packfile URIs and dumb HTTP are
safer by avoiding concurrent appends to the staging file. Opening in
read-write mode with separate file offsets prevents corruption and
preserves resumability. 'fetch-pack' now tolerates pre-existing
'.keep' files.
* tn/packfile-uri-concurrency:
fetch-pack: accept "pack" output for packfile URIs
http: permit unlinking partial packs on Windows
http: avoid concurrent appends to partial packs
http: accept HTTP 416 for complete partial packs
http: avoid closing index-pack input twice
http-fetch: correct --index-pack-arg documentation
The 'TRACE2_ANCESTRY' prerequisite in the 't0213' test script has been
refined to avoid failures under user-mode emulation by verifying that
the ancestry collector reports the expected process names rather than
the emulator binary name.
* jm/t0213-skip-emulated-ancestry-tests:
t0213: skip ancestry tests under user-mode emulation
Tests for 'git merge-base --is-ancestor' have been added to cover
exit codes (0 for success, 1 for non-ancestor, 128 for errors) and
to ensure it cannot be combined with '--all'.
* ns/merge-base-is-ancestor-tests:
merge-base: add tests for --is-ancestor
'git mv' has been updated to check for a missing destination
leading directory during the checking phase, allowing 'git mv -n'
to report the failure. The error message when the rename(2)
syscall fails has also been improved to name both the source and
the destination.
* lo/mv-missing-dest-dir-check:
mv: reject a destination whose leading path is missing or a symlink
mv: name both source and destination when rename fails
Documentation for 'git replay' has been updated to refer to its
configuration variables.
* kh/doc-replay-config:
doc: replay: move “default” to the right-hand side
doc: replay: use a nested description list
doc: replay: improve config description
doc: link to config for git-replay(1)
A new test helper commit_body() has been introduced to print the
message body of a commit, and various tests have been updated to use
it instead of spelling out the command pipeline manually and losing
the exit status of the 'git cat-file' command on the upstream of the
pipe.
* sk/test-commit-body-helper:
t: use commit_body to extract commit message bodies
test-lib-functions: add commit_body helper
Synopsis and options in the documentation for 'git format-patch',
'git imap-send', 'git send-email', and 'git request-pull' have been
updated to the modern style.
* ja/doc-synopsis-style-yet-more:
doc: convert git-request-pull synopsis and options to new style
doc: convert git-send-email synopsis and options to new style
doc: convert git-format-patch synopsis and options to new style
doc: convert git-imap-send synopsis and options to new style
Comment lines have always been ignored but this is not documented.
The primary motivation here is to be reasonably complete in the
documentation of how trailers are parsed; this is after all the only
documentation page that documents this format. However, and going beyond
that point, we could imagine that someone would want to use this format
outside a commit (or tag) message context, like say in Git notes.
On the other hand, it seems far-fetched that someone would be caught
off guard by this considering that comment characters/strings are not
likely to be alphanumeric,[1] which would mean that these comment lines
would be treated as non-trailer lines if they were *not* detected and
removed as comment lines.
† 1: A notable exception is that Jujutsu VCS uses `JJ:` as
the comment string
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Two commits ago we moved new-trailers paragraph next to each other.
But there is something curious about two of them:
By default the new trailer will appear at the end of the trailer
block. [...]
Then a source block and a paragraph later:
By default, a `<key>=<value>` or `<key>:<value>` argument given
using `--trailer` will be appended after the existing trailers only
if [...]
Why are there two paragraphs that talk about how “By default” a trailer
will be appended?
We can make these paragraphs flow better, and with a more distinct
character each, by dividing the flow like this:
1. Declare that we are about to talk about `--trailer` appending
2. Explain the default behavior
3. Explain how this affects the trailer block
4. Then discuss what each trailer line will look like
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We chose to introduce the term “trailer block” into the documentation a
few commits ago.[1] It is used in the code though, so it is not a newly
invented term.
That term was useful to explain where the trailers are found (they
*trail* the message). But it is also useful here, where we explain
how trailers are added to existing messages, how trailer blocks are
found (beyond the simple case in the introduction), and how the end
of the message is found.
Also note that we simplify the “blank line” point. The text says:
A blank line will be added before the new trailer if there isn't one
already.
But this isn’t quite coherent. The previous sentence says “If there is
no existing trailer”, so we are in one of these modes:
1. discussing trailer blocks in general; or
2. discussing creating a new trailer block in particular.
If (1), then we shouldn’t add a blank line before the new trailer if
there exists a trailer block already. And if (2), then the “if there
isn’t one already” is redundant.[2] So just talking about the higher-
level “trailer block” simplifies the text, since we don’t have to worry
about the different contexts that *trailers* can find themselves in.
† 1: in commit “explain the format after the intro”
† 2: Note that non-trailer lines don’t matter here; if you have a
trailer block consisting of `(cherry picked from commit <commit>)`,
then you still shouldn’t insert a blank line before the new trailer
since that would create a new trailer block
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are three paragraphs that talk about how a new trailer is added.
But the first one is separated from the other two by two paragraphs
about how `key-alias` can make using `--trailer` more convenient. This
short how-to does not follow thematically from the previous paragraph,
and can wait until we have fully described how a new trailer is
added. So let’s move the three paragraphs about the new-trailer topic
together and move the how-to paragraphs after that.
***
Let’s now review the history of the document. Even if the document
is not quite correct in its current state, just doing the apparently
obvious edit without considering the history does not respect the
effort that went into changing the document in the past.
These three paragraphs were originally next to each other, in the first
version of the doc.[1] But extra sentences about this how-to topic was
added to the first paragraph nine years later:[2]
[...]
`': '` (one colon followed by one space). For convenience, the
<token> can be a shortened string key (e.g., "sign") instead of the
full string which should [...]
And then it was split into it’s own paragraph a little later.[3]
This evolution shows, in my opinion, that this how-to never followed
thematically from the existing topic. Which means that there is nothing
that was potentially lost to time that we need to restore or respect.
† 1: dfd66ddf (Documentation: add documentation for 'git
interpret-trailers', 2014-10-13)
† 2: eda2c44c (doc: trailer: mention 'key' in DESCRIPTION, 2023-06-15)
† 3: 6ccbc667 (trailer doc: <token> is a <key> or <keyAlias>, not both,
2023-09-07)
Suggested-by: D. Ben Knoble <ben.knoble+github@gmail.com>
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All of the examples speak of the Happy Path where everything works
as intended. But failure examples can also be instructive. Especially
for explaining again, by example, the key format (see previous commit).
This also allows us to demonstrate trailer block detection with a
concrete example.
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A trailer key must consist of ASCII alphanumeric characters and
hyphens *only*. Let’s document it explicitly instead of relying on
readers being conservative and only basing their trailer keys on the
documentation examples.[1]
The previous commit provided us with an appropriate paragraph to
describe the key format.
† 1: Technically they would then miss out on using digits in them since
all of the example keys just use letters and hyphens
Reported-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
You need to read the entire “Description” section in order to understand
the full trailer format. But there are many nuances, so that’s fine.
As a starter though we have an introductory example.[1] That turns out
to be crucial; the rest of this section talks about the mechanics of the
command and only incidentally the format itself.
Now, although the example might arguably be self-explanatory, we can
add a little preamble which defines the format in its simplest form as
well as define the most important terms.
Note that we name the “blank line” rule since I want to use that term
every time it comes up. It gets very mildly obfuscated if you call it
a “blank line” in one place[2] and “empty (or whitespace-only) ...” in
another one.[3]
We will define the format of the *key* in the next commit.
† 1: from d57fa7fc (doc: trailer: add more examples in DESCRIPTION,
2023-06-15)
† 2: `Documentation/git-interpret-trailers.adoc:86` in
5361983c (The 22nd batch, 2026-03-27)
† 3: `Documentation/git-interpret-trailers.adoc:93` in
5361983c (The 22nd batch, 2026-03-27)
Suggested-by: D. Ben Knoble <ben.knoble+github@gmail.com>
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This command doesn’t interface with commits directly. You can
interpret or modify any kind of text, even though commit messages
are the most relevant.
The git(1) suite also isn’t restricted to only direct commit support
since git-tag(1) learned `--trailer` in 066cef77 (builtin/tag: add
--trailer option, 2024-05-05)
Now, we already introduce the command in the “Name” section as dealing
with commit messages as well. That is fine since that intro line needs
to remain pretty short.
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We now since the previous commit introduce the format as “trailer
metadata”. We can replace “structured information” with “metadata”
in the “Name” section to be consistent.
While “structured information” does emphasize that the data is not
loosely structured, we also say that this command adds to or parses
this format. I don’t think that we need to emphasize that it is
structured since clearly there is some structure there.
Both “metadata” and “structured information” can convey the same
information. But “metadata” is shorter and easier to deploy since
it’s just one word.
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We removed the initial comparison to email headers in the previous
commit. Now the introduction paragraph just says “trailer lines”, and
the only hint that this is metadata/structured information is the
“otherwise free-form” phrase.
Let’s replace “lines” with “metadata” since that is their purpose.
This also makes the introduction more consistent with how I chose
to define trailers in the glossary:[1] “Key-value metadata”. (We will
introduce “key–value” in the upcoming commit “explain the format after
the intro”.)
† 1: 68e3c69e (Documentation/glossary: describe "trailer", 2024-11-17)
Let’s not emphasize “trailer” here since we are going to define the term
in the upcoming commit “explain the format after the intro”.
Let’s call it “trailer metadata” rather than “trailers metadata”.
At first it seemed better to use the latter:
1. We’re introducing the jargon, and the format is often discussed as
plural “trailers”, with its constituent parts being singular
“trailer”
2. What this replaces uses “trailer”, but it rescues the plural mood
with “lines”
3. This is very soon going to go into the constituent parts, including
each trailer, so we’re contrasting the concept name (trailers) with
its parts
But:
1. The former reads better (most important)
2. “Trailer *metadata*” suggests plurality, similar to “trailer *lines*”
Helped-by: Matt Hunter <m@lfurio.us>
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This command handles the trailer metadata format. But the command
isn’t introduced as such; it is instead introduced by stating that
these trailer lines look similar to RFC 822 email headers.
This is overwrought; most people do not deal directly with email
headers, and certainly not email RFCs.
Trailers are just key–value pairs that, like email headers, use colon
as the separator. The format in its simplest form is easy to describe
directly without comparing it to anything else; we will do that in the
upcoming commit “explain the format after the intro”.
For now, let’s:
• remove the first mention of email headers;
• keep the second, innocuous comparison with email line folding in the
middle; and
• remove the now-unneeded disclaimer that trailers do not share many of
the features of RFC 822 email headers—there is no invitation to
speculate that trailers would follow any other email format rules
since we do not compare them directly any more.
***
Talking about trailers as an RFC 822/2822-like format seems to go back
to the `--fixes`/`Fixes:` trailer topic,[1] the thread that precipitated
this command and in turn the first trailer support in git(1) beyond
adding s-o-b lines.
† 1: https://lore.kernel.org/all/20131027071407.GA11683@leaf/
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A crash in the 'sparse-index' collapse code when encountering an
invalidated cache-tree node (due to an intent-to-add path) has been
fixed by avoiding collapsing such subtrees.
* ds/sparse-index-ita-crash:
sparse-index: avoid crash on intent-to-add entry outside the cone
A boundary case check in reachability bitmap traversal has been
corrected to properly handle the object at position zero, which was
previously skipped, leading to redundant bitmap loading.
* dl/pack-bitmap-position-zero:
pack-bitmap: handle objects at bitmap position zero
A memory leak in 'git merge' when run without arguments (which
triggers the default-to-upstream path) has been fixed. A test has
been added to cover this case.
* tc/merge-default-to-upstream-leakfix:
merge: fix leak with merge.defaultToUpstream
'git cat-file --batch-command' that asked for 'contents' without
'type' segfaults, which has been corrected.
* jk/cat-file-batch-wo-type-fix:
cat-file: handle content request for --batch-command without type
The get_commit_action() function has been refactored to be a pure
predicate by moving the side-effecting line-level log range folding to
simplify_commit(). This ensures that evaluating a commit's action
before the walk reaches it does not prematurely mutate its tracked
line ranges, making it safer for potential lookahead evaluations.
* mm/revision-pure-get-commit-action:
revision: make get_commit_action() a pure predicate
The code path that deals with relative paths in the 'diff-lib' has
been cleaned up.
* jk/diff-relative-cached-unmerged-more:
diff-lib: skip paths outside prefix in oneway_diff()
diff-lib: drop stale comment about advancing o->pos
When answering a `cat-blob` command, `cat_blob()` issues three separate
calls to write(3p) on the cat-blob fd: one for the header line, one for
the full blob payload, and one for the trailing newline. Frontends like
git-filter-repo issue these commands in bulk, once per rewritten blob,
so the syscall overhead adds up.
Use `writev_in_full()` to send all three parts with a single syscall.
This can be benchmarked with the following setup:
$ git cat-file --unordered --filter=object:type=blob
--batch-check='cat-blob %(objectname)' --batch-all-objects >request
$ git fast-import --cat-blob-fd=3 <request
Executing this with 100,000 objects in linux.git:
Benchmark 1: HEAD~
Time (mean ± σ): 1.320 s ± 0.003 s [User: 1.154 s, System: 0.161 s]
Range (min … max): 1.314 s … 1.324 s 10 runs
Benchmark 2: HEAD
Time (mean ± σ): 1.270 s ± 0.022 s [User: 1.133 s, System: 0.132 s]
Range (min … max): 1.209 s … 1.282 s 10 runs
Summary
HEAD ran
1.04 ± 0.02 times faster than HEAD~
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Every pktline that we send out via `send_sideband()` currently requires
two syscalls: one to write the pktline's length, and one to send its
data. This typically isn't all that much of a problem, but under extreme
load the syscalls may cause contention in the kernel.
Refactor the code to instead use the newly introduced writev(3p) infra
so that we can send out the data with a single syscall. This reduces the
number of syscalls from around 133,000 calls to write(3p) to around
67,000 calls to writev(3p).
This change leads to a performance improvement for git-upload-pack(1),
but we have to cheat a bit to really make it measurable. Usually, the
time is strongly dominated by generating the packfile itself. But if we
precompute the pack and serve it via the pack-objects hook then we can
essentially eliminate that overhead. The following setup is executed in
the Git repository:
$ cat >request <<-EOF
0048want 5ce91c059e side-band no-progress
00000009done
EOF
$ echo 5ce91c059e | git pack-objects --revs --stdout >pack
$ cat >hook <<-EOF
#!/bin/sh
cat >/dev/null
cat "$(pwd)"/pack
EOF
$ chmod u+x hook
$ git -c uploadpack.packObjectsHook="$(pwd)"/hook upload-pack . <request
Benchmarking the last command leads to the following results:
Benchmark 1: HEAD~
Time (mean ± σ): 192.9 ms ± 0.6 ms [User: 106.5 ms, System: 95.3 ms]
Range (min … max): 191.7 ms … 194.1 ms 50 runs
Benchmark 2: HEAD
Time (mean ± σ): 141.1 ms ± 0.7 ms [User: 63.2 ms, System: 86.6 ms]
Range (min … max): 139.8 ms … 142.7 ms 50 runs
Summary
HEAD ran
1.37 ± 0.01 times faster than HEAD~
This might not be impressive in absolute numbers when you also take into
account the time it takes to generate the packfile itself. But GitLab
(and supposedly other forges) have caching mechanisms in place that work
exactly like the above setup, where repeated incoming requests can be
served from the same cached packfile. And in those cases, the impact is
sizeable.
More importantly though, as hinted at above, GitLab has observed in the
past that with enough cache hits we eventually start to saturate a
semaphore in the Linux kernel itself in the pipe write path. This
bottleneck is being moved a bit by having to do less syscalls.
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some systems like NonStop set a comparatively small `MAX_IO_SIZE`, which
limits the maximum number of bytes we're allowed to write in a single
call. We already handle this limit properly in `xwrite()`, but we have
recently introduced wrappers for writev(3p) where we don't. This will
cause the syscall to return EINVAL in case somebody passes an iovec
entry to writev(3p) that is larger than `MAX_IO_SIZE`.
Introduce a new function `xwritev()` that is similar to `xwrite()` in
that it handles such platform-specific nuances:
- We only pass the leading iovec entries to writev(3p) that fit into
`MAX_IO_SIZE`, pretending that the underlying syscall performed a
short write. This mirrors how `xwrite()` chomps overly large
requests before handing them to write(3p). As a consequence, callers
will never see writev(3p)'s EINVAL error for requests whose summed
length would overflow an ssize_t, but observe a short write instead.
- If already the first iovec entry exceeds the limit we instead punt
to `xwrite()`, which knows to handle this case for us.
- We restart the underlying syscall on EINTR and EAGAIN, just like
`xwrite()` does for write(3p).
Adapt `writev_in_full()` to use this new wrapper. With the retry logic
now living in `xwritev()`, the calling loop becomes the exact mirror
image of `write_in_full()`, which also retains the responsibility of
translating a zero-length write into ENOSPC.
Reported-by: Randall Becker <randall.becker@nexbridge.ca>
Helped-by: Jeff King <peff@peff.net>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the preceding commit we have added a compatibility wrapper for the
writev(3p) syscall. Introduce some generic wrappers for this function
that we nowadays take for granted in the Git codebase.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a subsequent commit we're going to add the first caller to
writev(3p). Introduce a compatibility wrapper for this syscall that we
can use on systems that don't have this syscall.
The syscall exists on modern Unixes like Linux and macOS, and seemingly
even for NonStop according to [1]. It doesn't seem to exist on Windows
though.
[1]: http://nonstoptools.com/manuals/OSS-SystemCalls.pdf
[2]: https://www.gnu.org/software/gnulib/manual/html_node/writev.html
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When creating a new "files" object database source we have to create a
couple of directories. These directories are of course specific to this
particular backend, and a different backend may require a setup that is
completely different.
Make the creation of on-disk structures pluggable to accommodate for
this.
Note that there is one exception though: the "objects" directory must
exist in a repository regardless of which backend is in use. If it
doesn't exist then the repository is not treated as a Git repository at
all. Consequently, we create this directory regardless of the backend.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce a new function that maps an object source's type to a
human-readable name. Use the function to provide better human-readable
error messages for the downcasting functions.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a subsequent commit we'll make the creation of the on-disk data
structures of an object database pluggable. This will lead to an
in-between state where we have already configured the repository's
object database, but it's not usable yet until we eventually call
`create_object_directory()`.
Lift the call to `odb_new()` out of `apply_repository_format()` so that
callers have more wiggle room with when exactly they call it, and adapt
them accordingly. The only exception is `init_db()`, where we now defer
creating the object database until we call `create_object_database()`.
With this change, initializing and creating the object database on disk
is now neatly encapsulated in a single function, which will make it
easier for a subsequent commit to move creation of the on-disk data
structures into the `struct odb_source` backends.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When initializing a repository's object database we have to respect the
GIT_OBJECT_DIRECTORY and GIT_ALTERNATE_OBJECT_DIRECTORIES environment
variables, which can be set by the user to override the default location
of where we write objects to and read objects from.
This is handled in `apply_repository_format()`, which is fine. But in a
subsequent commit we'll have to defer constructing the object database
to a later point in some cases, and that will require a second site
where we call `odb_new()`. And of course, that second site would have to
handle those environment variables, as well.
It would be somewhat awkward to duplicate the logic though. But there's
a better alternative: instead of handling this logic in "setup.c", we
can easily handle environment variables in `odb_new()` itself. This
ensures that object database creation is neatly self-contained, and we
don't have to duplicate any of the logic.
Another benefit is that in a future patch series we plan to move
handling of alternates into the backends themselves [1], and that will
require us to also handle those environment variables in the "files"
backend itself. So moving the logic into the ODB level already gets us
one step closer to that goal.
Refactor the logic accordingly.
[1]: https://lore.kernel.org/git/amLgMqkqxR8mKIbT@pks.im/
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a repository is configured to use a compatibility hash function
then we load the loose object map when we initialize the repository.
This object map provides the mappings between the canonical object hash
and the compatibility object hash.
Loading the object map happens in `repo_set_compat_hash_algo()`, which
calls `repo_read_loose_object_map()` in case the compatibility object
hash is non-zero. This setup sequence has two major downsides:
- We assume that the primary object database is the "files" object
database and unconditionally downcast it. This will cause us to BUG
in case a different object database type was used together with a
compat hash algorithm.
- We require the object database to already have been initialized when
configuring the object database. This means that we must intermix
configuration of the repository and initialization of its
sub-structures in a weird way.
Refactor the logic so that we instead load the loose object map via the
"loose" backend, which fixes both of the above issues.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When loading the loose object map via `load_one_loose_object_map()` we
pass in both a repository and the corresponding source. We ultimately
don't really respect the passed-in source though as we instead always
load the map via the common directory. This doesn't make any sense
though, as the function is called in a loop through all sources, and as
such the expectation is that we'll load the map that belongs to the
given source. The consequence is that we'll ignore loose object maps of
any configured alternates.
Fix this bug by instead loading the map via the loose source's path.
Helped-by: Toon Claes <toon@iotcl.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Volodymyr Vriukalo