Commit Graph

169 Commits (maint)

Author SHA1 Message Date
shejialuo 86ddd588f2 packed-backend: mmap large "packed-refs" file during fsck
During fsck, we use "strbuf_read" to read the content of "packed-refs"
without using mmap mechanism. This is a bad practice which would consume
more memory than using mmap mechanism. Besides, as all code paths in
"packed-backend.c" use this way, we should make "fsck" align with the
current codebase.

As we have introduced the helper function "allocate_snapshot_buffer", we
can simply use this function to use mmap mechanism.

Suggested-by: Jeff King <peff@peff.net>
Suggested-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-14 12:32:59 -07:00
shejialuo a0dee3f74b packed-backend: extract snapshot allocation in `load_contents`
"load_contents" would choose which way to load the content of the
"packed-refs". However, we cannot directly use this function when
checking the consistency due to we don't want to open the file. And we
also need to reuse the logic to avoid causing repetition.

Let's create a new helper function "allocate_snapshot_buffer" to extract
the snapshot allocation logic in "load_contents" and update the
"load_contents" to align with the behavior.

Suggested-by: Jeff King <peff@peff.net>
Suggested-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-14 12:32:58 -07:00
shejialuo 784ceccb91 packed-backend: fsck should warn when "packed-refs" file is empty
We assume the "packed-refs" won't be empty and instead has at least one
line in it (even when there are no refs packed, there is the file header
line). Because there is no terminating LF in the empty file, we will
report "packedRefEntryNotTerminated(ERROR)" to the user.

However, the runtime code paths would accept an empty "packed-refs"
file, for example, "create_snapshot" would simply return the "snapshot"
without checking the content of "packed-refs". So, we should skip
checking the content of "packed-refs" when it is empty during fsck.

After 694b7a1999 (repack_without_ref(): write peeled refs in the
rewritten file, 2013-04-22), we would always write a header into the
"packed-refs" file. So, versions of Git that are not too ancient never
write such an empty "packed-refs" file.

As an empty file often indicates a sign of a filesystem-level issue, the
way we want to resolve this inconsistency is not make everybody totally
silent but notice and report the anomaly.

Let's create a "FSCK_INFO" message id "EMPTY_PACKED_REFS_FILE" to report
to the users that "packed-refs" is empty.

Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-14 12:32:58 -07:00
Junio C Hamano c81538ea6c Merge branch 'ps/refname-avail-check-optim'
Incorrect sorting of refs with bytes with high-bit set on platforms
with signed char led to a BUG, which has been corrected.

* ps/refname-avail-check-optim:
  refs/packed: fix BUG when seeking refs with UTF-8 characters
2025-04-17 10:28:19 -07:00
Junio C Hamano 47478802da Merge branch 'kn/non-transactional-batch-updates'
Updating multiple references have only been possible in all-or-none
fashion with transactions, but it can be more efficient to batch
multiple updates even when some of them are allowed to fail in a
best-effort manner.  A new "best effort batches of updates" mode
has been introduced.

* kn/non-transactional-batch-updates:
  update-ref: add --batch-updates flag for stdin mode
  refs: support rejection in batch updates during F/D checks
  refs: implement batch reference update support
  refs: introduce enum-based transaction error types
  refs/reftable: extract code from the transaction preparation
  refs/files: remove duplicate duplicates check
  refs: move duplicate refname update check to generic layer
  refs/files: remove redundant check in split_symref_update()
2025-04-16 13:54:19 -07:00
Patrick Steinhardt f1fb064465 refs/packed: fix BUG when seeking refs with UTF-8 characters
It was reported that using git-pull(1) in a repository whose remote
contains branches with emojis leads to the following bug:

    $ git pull
    remote: Enumerating objects: 161255, done.
    remote: Counting objects: 100% (55884/55884), done.
    remote: Compressing objects: 100% (5518/5518), done.
    remote: Total 161255 (delta 54253), reused 50509 (delta 50364),
    pack-reused 105371 (from 4)
    Receiving objects: 100% (161255/161255), 309.90 MiB | 16.87 MiB/s, done.
    Resolving deltas: 100% (118048/118048), completed with 13416 local objects.
    From github.com:github/github
       97ab7ae3f3745..8fb2f9fa180ed  master -> origin/master
    [...snip many screenfuls of updates to origin remotes...]
    BUG: refs/packed-backend.c:984: packed-refs backend yielded reference
    preceding its prefix
    error: fetch died of signal 6

This issue bisects to 22600c0452 (refs/iterator: implement seeking for
packed-ref iterators, 2025-03-12) where we have implemented seeking for
the packed-ref iterator. As part of that change we introduced a check
that verifies that the iterator only returns refnames bigger than the
prefix. In theory, this check should always hold: when a prefix is set
we know that we would've seeked that prefix first, so we should never
see a reference sorting before that prefix.

But in practice the check itself is misbehaving when handling unicode
characters. The particular issue triggered with a branch that got the
"shaved ice" unicode character in its name, which is composed of the
bytes "0xEE 0x90 0xBF". The bug triggers when we compare the refname
"refs/heads/<shaved-ice>" to something like "refs/heads/z", and it
specifically hits when comparing the first byte, "0xEE".

The root cause is that the most-significant bit of 0xEE is set. The
`refname` and `prefix` pointers that we use to compare bytes with one
another are both pointers to signed characters. As such, when we
dereference the 0xEE byte the result is a _negative_ value, and this
value will of course compare smaller than "z".

We can see that this issue is avoided in `cmp_packed_refname()`, where
we explicitly cast each byte to its unsigned form. Fix the bug by doing
the same in `packed_ref_iterator_advance()`.

Reported-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-09 09:14:32 -07:00
Karthik Nayak 23fc8e4f61 refs: implement batch reference update support
Git supports making reference updates with or without transactions.
Updates with transactions are generally better optimized. But
transactions are all or nothing. This means, if a user wants to batch
updates to take advantage of the optimizations without the hard
requirement that all updates must succeed, there is no way currently to
do so. Particularly with the reftable backend where batching multiple
reference updates is more efficient than performing them sequentially.

Introduce batched update support with a new flag,
'REF_TRANSACTION_ALLOW_FAILURE'. Batched updates while different from
transactions, use the transaction infrastructure under the hood. When
enabled, this flag allows individual reference updates that would
typically cause the entire transaction to fail due to non-system-related
errors to be marked as rejected while permitting other updates to
proceed. System errors referred by 'REF_TRANSACTION_ERROR_GENERIC'
continue to result in the entire transaction failing. This approach
enhances flexibility while preserving transactional integrity where
necessary.

The implementation introduces several key components:

  - Add 'rejection_err' field to struct `ref_update` to track failed
    updates with failure reason.

  - Add a new struct `ref_transaction_rejections` and a field within
    `ref_transaction` to this struct to allow quick iteration over
    rejected updates.

  - Modify reference backends (files, packed, reftable) to handle
    partial transactions by using `ref_transaction_set_rejected()`
    instead of failing the entire transaction when
    `REF_TRANSACTION_ALLOW_FAILURE` is set.

  - Add `ref_transaction_for_each_rejected_update()` to let callers
    examine which updates were rejected and why.

This foundational change enables batched update support throughout the
reference subsystem. A following commit will expose this capability to
users by adding a `--batch-updates` flag to 'git-update-ref(1)',
providing both a user-facing feature and a testable implementation.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08 07:57:20 -07:00
Karthik Nayak 76e760b999 refs: introduce enum-based transaction error types
Replace preprocessor-defined transaction errors with a strongly-typed
enum `ref_transaction_error`. This change:

  - Improves type safety and function signature clarity.
  - Makes error handling more explicit and discoverable.
  - Maintains existing error cases, while adding new error cases for
    common scenarios.

This refactoring paves the way for more comprehensive error handling
which we will utilize in the upcoming commits to add batch reference
update support.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08 07:57:20 -07:00
Karthik Nayak c3baddf04f refs: move duplicate refname update check to generic layer
Move the tracking of refnames in `affected_refnames` from individual
backends into the generic layer in 'refs.c'. This centralizes the
duplicate refname detection that was previously handled separately by
each backend.

Make some changes to accommodate this move:

  - Add a `string_list` field `refnames` to `ref_transaction` to contain
    all the references in a transaction. This field is updated whenever
    a new update is added via `ref_transaction_add_update`, so manual
    additions in reference backends are dropped.

  - Modify the backends to use this field internally as needed. The
    backends need to check if an update for refname already exists when
    splitting symrefs or adding an update for 'HEAD'.

  - In the reftable backend, within `reftable_be_transaction_prepare()`,
    move the `string_list_has_string()` check above
    `ref_transaction_add_update()`. Since `ref_transaction_add_update()`
    automatically adds the refname to `transaction->refnames`,
    performing the check after will always return true, so we perform
    the check before adding the update.

This helps reduce duplication of functionality between the backends and
makes it easier to make changes in a more centralized manner.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08 07:57:18 -07:00
Junio C Hamano 8d6413a1be Merge branch 'ps/refname-avail-check-optim'
The code paths to check whether a refname X is available (by seeing
if another ref X/Y exists, etc.) have been optimized.

* ps/refname-avail-check-optim:
  refs: reuse iterators when determining refname availability
  refs/iterator: implement seeking for files iterators
  refs/iterator: implement seeking for packed-ref iterators
  refs/iterator: implement seeking for ref-cache iterators
  refs/iterator: implement seeking for reftable iterators
  refs/iterator: implement seeking for merged iterators
  refs/iterator: provide infrastructure to re-seek iterators
  refs/iterator: separate lifecycle from iteration
  refs: stop re-verifying common prefixes for availability
  refs/files: batch refname availability checks for initial transactions
  refs/files: batch refname availability checks for normal transactions
  refs/reftable: batch refname availability checks
  refs: introduce function to batch refname availability checks
  builtin/update-ref: skip ambiguity checks when parsing object IDs
  object-name: allow skipping ambiguity checks in `get_oid()` family
  object-name: introduce `repo_get_oid_with_flags()`
2025-03-29 16:39:07 +09:00
Patrick Steinhardt 22600c0452 refs/iterator: implement seeking for packed-ref iterators
Implement seeking of `packed-ref` iterators. The implementation is again
straight forward, except that we cannot continue to use the prefix
iterator as we would otherwise not be able to reseek the iterator
anymore in case one first asks for an empty and then for a non-empty
prefix. Instead, we open-code the logic to in `advance()`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-12 11:31:20 -07:00
Patrick Steinhardt cec2b6f55a refs/iterator: separate lifecycle from iteration
The ref and reflog iterators have their lifecycle attached to iteration:
once the iterator reaches its end, it is automatically released and the
caller doesn't have to care about that anymore. When the iterator should
be released before it has been exhausted, callers must explicitly abort
the iterator via `ref_iterator_abort()`.

This lifecycle is somewhat unusual in the Git codebase and creates two
problems:

  - Callsites need to be very careful about when exactly they call
    `ref_iterator_abort()`, as calling the function is only valid when
    the iterator itself still is. This leads to somewhat awkward calling
    patterns in some situations.

  - It is impossible to reuse iterators and re-seek them to a different
    prefix. This feature isn't supported by any iterator implementation
    except for the reftable iterators anyway, but if it was implemented
    it would allow us to optimize cases where we need to search for
    specific references repeatedly by reusing internal state.

Detangle the lifecycle from iteration so that we don't deallocate the
iterator anymore once it is exhausted. Instead, callers are now expected
to always call a newly introduce `ref_iterator_free()` function that
deallocates the iterator and its internal state.

Note that the `dir_iterator` is somewhat special because it does not
implement the `ref_iterator` interface, but is only used to implement
other iterators. Consequently, we have to provide `dir_iterator_free()`
instead of `dir_iterator_release()` as the allocated structure itself is
managed by the `dir_iterator` interfaces, as well, and not freed by
`ref_iterator_free()` like in all the other cases.

While at it, drop the return value of `ref_iterator_abort()`, which
wasn't really required by any of the iterator implementations anyway.
Furthermore, stop calling `base_ref_iterator_free()` in any of the
backends, but instead call it in `ref_iterator_free()`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-12 11:31:18 -07:00
shejialuo e1c9548eae packed-backend: check whether the "packed-refs" is sorted
When there is a "sorted" trait in the header of the "packed-refs" file,
it means that each entry is sorted increasingly by comparing the
refname. We should add checks to verify whether the "packed-refs" is
sorted in this case.

Update the "packed_fsck_ref_header" to know whether there is a "sorted"
trail in the header. It may seem that we could record all refnames
during the parsing process and then compare later. However, this is not
a good design due to the following reasons:

1. Because we need to store the state across the whole checking
   lifetime, we would consume a lot of memory if there are many entries
   in the "packed-refs" file.
2. We cannot reuse the existing compare function "cmp_packed_ref_records"
   which cause repetition.

Because "cmp_packed_ref_records" needs an extra parameter "struct
snaphost", extract the common part into a new function
"cmp_packed_ref_records" to reuse this function to compare.

Then, create a new function "packed_fsck_ref_sorted" to parse the file
again and user the new fsck message "packedRefUnsorted(ERROR)" to report
to the user if the file is not sorted.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-27 14:03:09 -08:00
shejialuo e6ba4c07b8 packed-backend: add "packed-refs" entry consistency check
"packed-backend.c::next_record" will parse the ref entry to check the
consistency. This function has already checked the following things:

1. Parse the main line of the ref entry to inspect whether the oid is
   not correct. Then, check whether the next character is oid. Then
   check the refname.
2. If the next line starts with '^', it would continue to parse the
   peeled oid and check whether the last character is '\n'.

As we decide to implement the ref consistency check for "packed-refs",
let's port these two checks and update the test to exercise the code.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-27 14:03:08 -08:00
shejialuo 5637d55420 packed-backend: check whether the refname contains NUL characters
"packed-backend.c::next_record" will use "check_refname_format" to check
the consistency of the refname. If it is not OK, the program will die.
However, it is reported in [1], we cannot catch some corruption. But we
already have the code path and we must miss out something.

We use the following code to get the refname:

    strbuf_add(&iter->refname_buf, p, eol - p);
    iter->base.refname = iter->refname_buf.buf

In the above code, `p` is the start pointer of the refname and `eol` is
the next newline pointer. We calculate the length of the refname by
subtracting the two pointers. Then we add the memory range between `p`
and `eol` to get the refname.

However, if there are some NUL characters in the memory range between `p`
and `eol`, we will see the refname as a valid ref name as long as the
memory range between `p` and first occurred NUL character is valid.

In order to catch above corruption, create a new function
"refname_contains_nul" by searching the first NUL character. If it is
not at the end of the string, there must be some NUL characters in the
refname.

Use this function in "next_record" function to die the program if
"refname_contains_nul" returns true.

[1] https://lore.kernel.org/git/6cfee0e4-3285-4f18-91ff-d097da9de737@rd10.de/

Reported-by: R. Diez <rdiez-temp3@rd10.de>
Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-27 14:03:08 -08:00
shejialuo c92e7e156e packed-backend: add "packed-refs" header consistency check
In "packed-backend.c::create_snapshot", if there is a header (the line
which starts with '#'), we will check whether the line starts with "#
pack-refs with: ". However, we need to consider other situations and
discuss whether we need to add checks.

1. If the header does not exist, we should not report an error to the
   user. This is because in older Git version, we never write header in
   the "packed-refs" file. Also, we do allow no header in "packed-refs"
   in runtime.
2. If the header content does not start with "# packed-ref with: ", we
   should report an error just like what "create_snapshot" does. So,
   create a new fsck message "badPackedRefHeader(ERROR)" for this.
3. If the header content is not the same as the constant string
   "PACKED_REFS_HEADER". This is expected because we make it extensible
   intentionally and runtime "create_snapshot" won't complain about
   unknown traits. In order to align with the runtime behavior. There is
   no need to report.

As we have analyzed, we only need to check the case 2 in the above. In
order to do this, use "open_nofollow" function to get the file
descriptor and then read the "packed-refs" file via "strbuf_read". Like
what "create_snapshot" and other functions do, we could split the line
by finding the next newline in the buffer. When we cannot find a
newline, we could report an error.

So, create a function "packed_fsck_ref_next_line" to find the next
newline and if there is no such newline, use
"packedRefEntryNotTerminated(ERROR)" to report an error to the user.

Then, parse the first line to apply the checks. Update the test to
exercise the code.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-27 14:03:08 -08:00
shejialuo 515579756c packed-backend: check if header starts with "# pack-refs with: "
We always write a space after "# pack-refs with:" but we don't align
with this rule in the "create_snapshot" method where we would check
whether header starts with "# pack-refs with:". It might seem that we
should undoubtedly tighten this rule, however, we don't have any
technical documentation about this and there is a possibility that we
would break the compatibility for other third-party libraries.

By investigating influential third-party libraries, we could conclude
how these libraries handle the header of "packed-refs" file:

1. libgit2 is fine and always writes the space. It also expects the
   whitespace to exist.
2. JGit does not expect th header to have a trailing space, but expects
   the "peeled" capability to have a leading space, which is mostly
   equivalent because that capability is typically the first one we
   write. It always writes the space.
3. gitoxide expects the space t exist and writes it.
4. go-git doesn't create the header by default.

As many third-party libraries expect a single space after "# pack-refs
with:", if we forget to write the space after the colon,
"create_snapshot" won't catch this. And we would break other
re-implementations. So, we'd better tighten the rule by checking whether
the header starts with "# pack-refs with: ".

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-27 14:03:07 -08:00
shejialuo cfea2f2da8 packed-backend: check whether the "packed-refs" is regular file
Although "git-fsck(1)" and "packed-backend.c" will check some
consistency and correctness of "packed-refs" file, they never check the
filetype of the "packed-refs". Let's verify that the "packed-refs" has
the expected filetype, confirming it is created by "git pack-refs"
command.

We could use "open_nofollow" wrapper to open the raw "packed-refs" file.
If the returned "fd" value is less than 0, we could check whether the
"errno" is "ELOOP" to report an error to the user. And then we use
"fstat" to check whether the "packed-refs" file is a regular file.

Reuse "FSCK_MSG_BAD_REF_FILETYPE" fsck message id to report the error to
the user if "packed-refs" is not a regular file.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-27 14:03:07 -08:00
Patrick Steinhardt 41f43b8243 global: mark code units that generate warnings with `-Wsign-compare`
Mark code units that generate warnings with `-Wsign-compare`. This
allows for a structured approach to get rid of all such warnings over
time in a way that can be easily measured.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-06 20:20:02 +09:00
Junio C Hamano 57e81b59f3 Merge branch 'sj/ref-contents-check'
"git fsck" learned to issue warnings on "curiously formatted" ref
contents that have always been taken valid but something Git
wouldn't have written itself (e.g., missing terminating end-of-line
after the full object name).

* sj/ref-contents-check:
  ref: add symlink ref content check for files backend
  ref: check whether the target of the symref is a ref
  ref: add basic symref content check for files backend
  ref: add more strict checks for regular refs
  ref: port git-fsck(1) regular refs check for files backend
  ref: support multiple worktrees check for refs
  ref: initialize ref name outside of check functions
  ref: check the full refname instead of basename
  ref: initialize "fsck_ref_report" with zero
2024-12-04 10:14:42 +09:00
shejialuo 7c78d819e6 ref: support multiple worktrees check for refs
We have already set up the infrastructure to check the consistency for
refs, but we do not support multiple worktrees. However, "git-fsck(1)"
will check the refs of worktrees. As we decide to get feature parity
with "git-fsck(1)", we need to set up support for multiple worktrees.

Because each worktree has its own specific refs, instead of just showing
the users "refs/worktree/foo", we need to display the full name such as
"worktrees/<id>/refs/worktree/foo". So we should know the id of the
worktree to get the full name. Add a new parameter "struct worktree *"
for "refs-internal.h::fsck_fn". Then change the related functions to
follow this new interface.

The "packed-refs" only exists in the main worktree, so we should only
check "packed-refs" in the main worktree. Use "is_main_worktree" method
to skip checking "packed-refs" in "packed_fsck" function.

Then, enhance the "files-backend.c::files_fsck_refs_dir" function to add
"worktree/<id>/" prefix when we are not in the main worktree.

Last, add a new test to check the refname when there are multiple
worktrees to exercise the code.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-11-21 08:21:32 +09:00
Patrick Steinhardt 1c299d03e5 refs: introduce "initial" transaction flag
There are two different ways to commit a transaction:

  - `ref_transaction_commit()` can be used to commit a regular
    transaction and is what almost every caller wants.

  - `initial_ref_transaction_commit()` can be used when it is known that
    the ref store that the transaction is committed for is empty and
    when there are no concurrent processes. This is used when cloning a
    new repository.

Implementing this via two separate functions has a couple of downsides.
First, every reference backend needs to implement a separate callback
even in the case where they don't special-case the initial transaction.
Second, backends are basically forced to reimplement the whole logic for
how to commit the transaction like the "files" backend does, even though
backends may wish to only tweak certain behaviour of a "normal" commit.
Third, it is awkward that callers must never prepare the transaction as
this is somewhat different than how a transaction typically works.

Refactor the code such that we instead mark initial transactions via a
separate flag when starting the transaction. This addresses all of the
mentioned painpoints, where the most important part is that it will
allow backends to have way more leeway in how exactly they want to
handle the initial transaction.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-11-21 07:59:15 +09:00
Junio C Hamano 143682ec43 Merge branch 'ps/pack-refs-auto-heuristics'
"git pack-refs --auto" for the files backend was too aggressive,
which has been a bit tamed.

* ps/pack-refs-auto-heuristics:
  refs/files: use heuristic to decide whether to repack with `--auto`
  t0601: merge tests for auto-packing of refs
  wrapper: introduce `log2u()`
2024-09-12 11:47:23 -07:00
Patrick Steinhardt c3459ae9ef refs/files: use heuristic to decide whether to repack with `--auto`
The `--auto` flag for git-pack-refs(1) allows the ref backend to decide
whether or not a repack is in order. This switch has been introduced
mostly with the "reftable" backend in mind, which already knows to
auto-compact its tables during normal operations. When the flag is set,
then it will use the same auto-compaction mechanism and thus end up
doing nothing in most cases.

The "files" backend does not have any such heuristic yet and instead
packs any loose references unconditionally. So we rewrite the complete
"packed-refs" file even if there's only a single loose reference to be
packed.

Even worse, starting with 9f6714ab3e (builtin/gc: pack refs when using
`git maintenance run --auto`, 2024-03-25), `git pack-refs --auto` is
unconditionally executed via our auto maintenance, so we end up repacking
references every single time auto maintenance kicks in. And while that
commit already mentioned that the "files" backend unconditionally packs
refs now, the author obviously didn't quite think about the consequences
thereof. So while the idea was sound, we really should have added a
heuristic to the "files" backend before implementing it.

Introduce a heuristic that decides whether or not it is worth to pack
loose references. The important factors to decide here are the number of
loose references in comparison to the overall size of the "packed-refs"
file. The bigger the "packed-refs" file, the longer it takes to rewrite
it and thus we scale up the limit of allowed loose references before we
repack.

As is the nature of heuristics, this mechansim isn't obviously
"correct", but should rather be seen as a tradeoff between how much
resources we spend packing refs and how inefficient the ref store
becomes. For all I can say, we have successfully been using the exact
same heuristic in Gitaly for several years by now.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-09-04 08:03:24 -07:00
Junio C Hamano 2b30d66c43 Merge branch 'jk/mark-unused-parameters'
Mark unused parameters as UNUSED to squelch -Wunused warnings.

* jk/mark-unused-parameters:
  t-hashmap: stop calling setup() for t_intern() test
  scalar: mark unused parameters in dummy function
  daemon: mark unused parameters in non-posix fallbacks
  setup: mark unused parameter in config callback
  test-mergesort: mark unused parameters in trivial callback
  t-hashmap: mark unused parameters in callback function
  reftable: mark unused parameters in virtual functions
  reftable: drop obsolete test function declarations
  reftable: ignore unused argc/argv in test functions
  unit-tests: ignore unused argc/argv
  t/helper: mark more unused argv/argc arguments
  oss-fuzz: mark unused argv/argc argument
  refs: mark unused parameters in do_for_each_reflog_helper()
  refs: mark unused parameters in ref_store fsck callbacks
  update-ref: mark more unused parameters in parser callbacks
  imap-send: mark unused parameter in ssl_socket_connect() fallback
2024-08-26 11:32:23 -07:00
Junio C Hamano 5e56a39e6a Merge branch 'ps/config-wo-the-repository'
Use of API functions that implicitly depend on the_repository
object in the config subsystem has been rewritten to pass a
repository object through the callchain.

* ps/config-wo-the-repository:
  config: hide functions using `the_repository` by default
  global: prepare for hiding away repo-less config functions
  config: don't depend on `the_repository` with branch conditions
  config: don't have setters depend on `the_repository`
  config: pass repo to functions that rename or copy sections
  config: pass repo to `git_die_config()`
  config: pass repo to `git_config_get_expiry_in_days()`
  config: pass repo to `git_config_get_expiry()`
  config: pass repo to `git_config_get_max_percent_split_change()`
  config: pass repo to `git_config_get_split_index()`
  config: pass repo to `git_config_get_index_threads()`
  config: expose `repo_config_clear()`
  config: introduce missing setters that take repo as parameter
  path: hide functions using `the_repository` by default
  path: stop relying on `the_repository` in `worktree_git_path()`
  path: stop relying on `the_repository` when reporting garbage
  hooks: remove implicit dependency on `the_repository`
  editor: do not rely on `the_repository` for interactive edits
  path: expose `do_git_common_path()` as `repo_common_pathv()`
  path: expose `do_git_path()` as `repo_git_pathv()`
2024-08-23 09:02:34 -07:00
Jeff King d1aa0fcd45 refs: mark unused parameters in ref_store fsck callbacks
Commit ab6f79d8df (refs: set up ref consistency check infrastructure,
2024-08-08) added virtual functions to the ref store for doing fsck
checks. But the packed and reftable backends do not yet do anything.

Let's annotate them to silence -Wunused-parameter.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-08-17 09:46:11 -07:00
Junio C Hamano b3d175409d Merge branch 'sj/ref-fsck'
"git fsck" infrastructure has been taught to also check the sanity
of the ref database, in addition to the object database.

* sj/ref-fsck:
  fsck: add ref name check for files backend
  files-backend: add unified interface for refs scanning
  builtin/refs: add verify subcommand
  refs: set up ref consistency check infrastructure
  fsck: add refs report function
  fsck: add a unified interface for reporting fsck messages
  fsck: make "fsck_error" callback generic
  fsck: rename objects-related fsck error functions
  fsck: rename "skiplist" to "skip_oids"
2024-08-16 12:51:51 -07:00
Patrick Steinhardt 219de841d9 global: prepare for hiding away repo-less config functions
We're about to hide config functions that implicitly depend on
`the_repository` behind the `USE_THE_REPOSITORY_VARIABLE` macro. This
will uncover a bunch of dependents that transitively relied on the
global variable, but didn't define the macro yet.

Adapt them such that we define the macro to prepare for this change.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-08-13 10:01:05 -07:00
shejialuo ab6f79d8df refs: set up ref consistency check infrastructure
The "struct ref_store" is the base class which contains the "be" pointer
which provides backend-specific functions whose interfaces are defined
in the "ref_storage_be". We could reuse this polymorphism to define only
one interface. For every backend, we need to provide its own function
pointer.

The interfaces defined in the `ref_storage_be` are carefully structured
in semantic. It's organized as the five parts:

1. The name and the initialization interfaces.
2. The ref transaction interfaces.
3. The ref internal interfaces (pack, rename and copy).
4. The ref filesystem interfaces.
5. The reflog related interfaces.

To keep consistent with the git-fsck(1), add a new interface named
"fsck_refs_fn" to the end of "ref_storage_be". This semantic cannot be
grouped into any above five categories. Explicitly add blank line to
make it different from others.

Last, implement placeholder functions for each ref backends.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-08-08 09:36:53 -07:00
Patrick Steinhardt 79e54c6a4e refs/packed: stop using `the_repository`
Convert the packed ref backend to stop using `the_repository` in favor
of the repo that gets passed in via `struct ref_store`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-07-30 13:41:24 -07:00
Patrick Steinhardt e7da938570 global: introduce `USE_THE_REPOSITORY_VARIABLE` macro
Use of the `the_repository` variable is deprecated nowadays, and we
slowly but steadily convert the codebase to not use it anymore. Instead,
callers should be passing down the repository to work on via parameters.

It is hard though to prove that a given code unit does not use this
variable anymore. The most trivial case, merely demonstrating that there
is no direct use of `the_repository`, is already a bit of a pain during
code reviews as the reviewer needs to manually verify claims made by the
patch author. The bigger problem though is that we have many interfaces
that implicitly rely on `the_repository`.

Introduce a new `USE_THE_REPOSITORY_VARIABLE` macro that allows code
units to opt into usage of `the_repository`. The intent of this macro is
to demonstrate that a certain code unit does not use this variable
anymore, and to keep it from new dependencies on it in future changes,
be it explicit or implicit

For now, the macro only guards `the_repository` itself as well as
`the_hash_algo`. There are many more known interfaces where we have an
implicit dependency on `the_repository`, but those are not guarded at
the current point in time. Over time though, we should start to add
guards as required (or even better, just remove them).

Define the macro as required in our code units. As expected, most of our
code still relies on the global variable. Nearly all of our builtins
rely on the variable as there is no way yet to pass `the_repository` to
their entry point. For now, declare the macro in "biultin.h" to keep the
required changes at least a little bit more contained.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-14 10:26:33 -07:00
Patrick Steinhardt 9da95bda74 hash: require hash algorithm in `oidread()` and `oidclr()`
Both `oidread()` and `oidclr()` use `the_repository` to derive the hash
function that shall be used. Require callers to pass in the hash
algorithm to get rid of this implicit dependency.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-14 10:26:32 -07:00
Patrick Steinhardt 64a6dd8ffc refs: implement removal of ref storages
We're about to introduce logic to migrate ref storages. One part of the
migration will be to delete the files that are part of the old ref
storage format. We don't yet have a way to delete such data generically
across ref backends though.

Implement a new `delete` callback and expose it via a new
`ref_storage_delete()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-06 09:04:33 -07:00
Junio C Hamano e55f364398 Merge branch 'ps/refs-without-the-repository-updates' into ps/ref-storage-migration
* ps/refs-without-the-repository-updates:
  refs/packed: remove references to `the_hash_algo`
  refs/files: remove references to `the_hash_algo`
  refs/files: use correct repository
  refs: remove `dwim_log()`
  refs: drop `git_default_branch_name()`
  refs: pass repo when peeling objects
  refs: move object peeling into "object.c"
  refs: pass ref store when detecting dangling symrefs
  refs: convert iteration over replace refs to accept ref store
  refs: retrieve worktree ref stores via associated repository
  refs: refactor `resolve_gitlink_ref()` to accept a repository
  refs: pass repo when retrieving submodule ref store
  refs: track ref stores via strmap
  refs: implement releasing ref storages
  refs: rename `init_db` callback to avoid confusion
  refs: adjust names for `init` and `init_db` callbacks
2024-05-23 09:14:08 -07:00
Patrick Steinhardt 00892786b8 refs/packed: remove references to `the_hash_algo`
Remove references to `the_hash_algo` in favor of the hash algo specified
by the repository associated with the packed ref store.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17 10:33:40 -07:00
Patrick Steinhardt 30aaff437f refs: pass repo when peeling objects
Both `peel_object()` and `peel_iterated_oid()` implicitly rely on
`the_repository` to look up objects. Despite the fact that we want to
get rid of `the_repository`, it also leads to some restrictions in our
ref iterators when trying to retrieve the peeled value for a repository
other than `the_repository`.

Refactor these functions such that both take a repository as argument
and remove the now-unnecessary restrictions.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17 10:33:39 -07:00
Patrick Steinhardt 71c871b48d refs: implement releasing ref storages
Ref storages are typically only initialized once for `the_repository`
and then never released. Until now we got away with that without causing
memory leaks because `the_repository` stays reachable, and because the
ref backend is reachable via `the_repository` its memory basically never
leaks.

This is about to change though because of the upcoming migration logic,
which will create a secondary ref storage. In that case, we will either
have to release the old or new ref storage to avoid leaks.

Implement a new `release` callback and expose it via a new
`ref_storage_release()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17 10:33:37 -07:00
Patrick Steinhardt ed93ea1602 refs: rename `init_db` callback to avoid confusion
Reference backends have two callbacks `init` and `init_db`. The
similarity of these two callbacks has repeatedly confused me whenever I
was looking at them, where I always had to look up which of them does
what.

Rename the `init_db` callback to `create_on_disk`, which should
hopefully be clearer.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17 10:33:36 -07:00
Patrick Steinhardt 1febabff7a refs: adjust names for `init` and `init_db` callbacks
The names of the functions that implement the `init` and `init_db`
callbacks in the "files" and "packed" backends do not match the names of
the callbacks, which is inconsistent. Rename them so that they match,
which makes it easier to discover their respective implementations.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17 10:33:36 -07:00
Karthik Nayak 4865707bda refs: remove `create_symref` and associated dead code
In the previous commits, we converted `refs_create_symref()` to utilize
transactions to perform symref updates. Earlier `refs_create_symref()`
used `create_symref()` to do the same.

We can now remove `create_symref()` and any code associated with it
which is no longer used. We remove `create_symref()` code from all the
reference backends and also remove it entirely from the `ref_storage_be`
struct.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-07 08:51:50 -07:00
Patrick Steinhardt 5e01d83841 refs: always treat iterators as ordered
In the preceding commit we have converted the reflog iterator of the
"files" backend to be ordered, which was the only remaining ref iterator
that wasn't ordered. Refactor the ref iterator infrastructure so that we
always assume iterators to be ordered, thus simplifying the code.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-21 09:58:06 -08:00
Junio C Hamano dc8ce995a2 Merge branch 'ps/worktree-refdb-initialization'
Instead of manually creating refs/ hierarchy on disk upon a
creation of a secondary worktree, which is only usable via the
files backend, use the refs API to populate it.

* ps/worktree-refdb-initialization:
  builtin/worktree: create refdb via ref backend
  worktree: expose interface to look up worktree by name
  builtin/worktree: move setup of commondir file earlier
  refs/files: skip creation of "refs/{heads,tags}" for worktrees
  setup: move creation of "refs/" into the files backend
  refs: prepare `refs_init_db()` for initializing worktree refs
2024-01-26 08:54:46 -08:00
Junio C Hamano 32c6fc3e30 Merge branch 'ps/refstorage-extension'
Introduce a new extension "refstorage" so that we can mark a
repository that uses a non-default ref backend, like reftable.

* ps/refstorage-extension:
  t9500: write "extensions.refstorage" into config
  builtin/clone: introduce `--ref-format=` value flag
  builtin/init: introduce `--ref-format=` value flag
  builtin/rev-parse: introduce `--show-ref-format` flag
  t: introduce GIT_TEST_DEFAULT_REF_FORMAT envvar
  setup: introduce GIT_DEFAULT_REF_FORMAT envvar
  setup: introduce "extensions.refStorage" extension
  setup: set repository's formats on init
  setup: start tracking ref storage format
  refs: refactor logic to look up storage backends
  worktree: skip reading HEAD when repairing worktrees
  t: introduce DEFAULT_REPO_FORMAT prereq
2024-01-16 10:11:57 -08:00
Junio C Hamano 492ee03f60 Merge branch 'en/header-cleanup'
Remove unused header "#include".

* en/header-cleanup:
  treewide: remove unnecessary includes in source files
  treewide: add direct includes currently only pulled in transitively
  trace2/tr2_tls.h: remove unnecessary include
  submodule-config.h: remove unnecessary include
  pkt-line.h: remove unnecessary include
  line-log.h: remove unnecessary include
  http.h: remove unnecessary include
  fsmonitor--daemon.h: remove unnecessary includes
  blame.h: remove unnecessary includes
  archive.h: remove unnecessary include
  treewide: remove unnecessary includes in source files
  treewide: remove unnecessary includes from header files
2024-01-08 14:05:15 -08:00
Patrick Steinhardt 2e573d61ff refs: prepare `refs_init_db()` for initializing worktree refs
The purpose of `refs_init_db()` is to initialize the on-disk files of a
new ref database. The function is quite inflexible right now though, as
callers can neither specify the `struct ref_store` nor can they pass any
flags.

Refactor the interface to accept both of these. This will be required so
that we can start initializing per-worktree ref databases via the ref
backend instead of open-coding the initialization in "worktree.c".

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-08 13:17:30 -08:00
Patrick Steinhardt 0fcc285c5e refs: refactor logic to look up storage backends
In order to look up ref storage backends, we're currently using a linked
list of backends, where each backend is expected to set up its `next`
pointer to the next ref storage backend. This is kind of a weird setup
as backends need to be aware of other backends without much of a reason.

Refactor the code so that the array of backends is centrally defined in
"refs.c", where each backend is now identified by an integer constant.
Expose functions to translate from those integer constants to the name
and vice versa, which will be required by subsequent patches.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-02 09:24:47 -08:00
Elijah Newren eea0e59ffb treewide: remove unnecessary includes in source files
Each of these were checked with
   gcc -E -I. ${SOURCE_FILE} | grep ${HEADER_FILE}
to ensure that removing the direct inclusion of the header actually
resulted in that header no longer being included at all (i.e. that
no other header pulled it in transitively).

...except for a few cases where we verified that although the header
was brought in transitively, nothing from it was directly used in
that source file.  These cases were:
  * builtin/credential-cache.c
  * builtin/pull.c
  * builtin/send-pack.c

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-12-26 12:04:31 -08:00
Patrick Steinhardt 29a186917b refs: remove `delete_refs` callback from backends
Now that `refs_delete_refs` is implemented in a generic way via the ref
transaction interfaces there are no callers left that invoke the
`delete_refs` callback anymore. Remove it from all of our backends.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-11-17 10:12:12 +09:00
Patrick Steinhardt d6f8e72982 refs: deduplicate code to delete references
Both the files and the packed-refs reference backends now use the same
generic transactions-based code to delete references. Let's pull these
implementations up into `refs_delete_refs()` to deduplicate the code.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-11-17 10:12:12 +09:00