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2025-10-13Merge branch 'kn/reftable-consistency-checks'Junio C Hamano5-22/+169
The reftable backend learned to sanity check its on-disk data more carefully. * kn/reftable-consistency-checks: refs/reftable: add fsck check for checking the table name reftable: add code to facilitate consistency checks fsck: order 'fsck_msg_type' alphabetically Documentation/fsck-msgids: remove duplicate msg id reftable: check for trailing newline in 'tables.list' refs: move consistency check msg to generic layer refs: remove unused headers
2025-10-07reftable: add code to facilitate consistency checksKarthik Nayak2-0/+140
The `git refs verify` command is used to run consistency checks on the reference backends. This command is also invoked when users run 'git fsck'. While the files-backend has some fsck checks added, the reftable backend lacks such checks. Let's add the required infrastructure and a check to test for the files present in the reftable directory. Since the reftable library is treated as an independent library we should ensure that the library code works independently without knowledge about Git's internals. To do this, add both 'reftable/fsck.c' and 'reftable/reftable-fsck.h'. Which provide an entry point 'reftable_fsck_check' for running fsck checks over a provided reftable stack. The callee provides the function with callbacks to handle issue and information reporting. The added check, goes over all tables in the reftable stack validates that they have a valid name. It not, it raises an error. While here, move 'reftable/error.o' in the Makefile to retain lexicographic ordering. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-10-07reftable: check for trailing newline in 'tables.list'Karthik Nayak3-22/+29
In the reftable format, the 'tables.list' file contains a newline separated list of tables. While we parse this file, we do not check or care about the last newline. Tighten the parser in `parse_names()` to return an appropriate error if the last newline is missing. This requires modification to `parse_names()` to now return the error while accepting the output as a third argument. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable: don't second-guess errors from flock interfacePatrick Steinhardt3-31/+12
The `flock` interface is implemented as part of "reftable/system.c" and thus needs to be implemented by the integrator between the reftable library and its parent code base. As such, we cannot rely on any specific implementation thereof. Regardless of that, users of the `flock` subsystem rely on `errno` being set to specific values. This is fragile and not documented anywhere and doesn't really make for a good interface. Refactor the code so that the implementations themselves are expected to return reftable-specific error codes. Our implementation of the `flock` subsystem already knows to do this for all error paths except one. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable/stack: handle outdated stacks when compactingPatrick Steinhardt1-6/+26
When we compact the reftable stack we first acquire the lock for the "tables.list" file and then reload the stack to check that it is still up-to-date. This is done by calling `stack_uptodate()`, which knows to return zero in case the stack is up-to-date, a positive value if it is not and a negative error code on unexpected conditions. We don't do proper error checking though, but instead we only check whether the returned error code is non-zero. If so, we simply bubble it up the calling stack, which means that callers may see an unexpected positive value. Fix this issue by translating to `REFTABLE_OUTDATED_ERROR` instead. Handle this situation in `reftable_addition_commit()`, where we perform a best-effort auto-compaction. All other callsites of `stack_uptodate()` know to handle a positive return value and thus don't need to be fixed. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable/stack: allow passing flags to `reftable_stack_add()`Patrick Steinhardt2-7/+10
The `reftable_stack_add()` function is a simple wrapper to lock the stack, add records to it via a callback and then commit the result. One problem with it though is that it doesn't accept any flags for creating the addition. This makes it impossible to automatically reload the stack in case it was modified before we managed to lock the stack. Add a `flags` field to plug this gap and pass it through accordingly. For now this new flag won't be used by us, but it will be used by libgit2. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable/stack: fix compiler warning due to missing bracesPatrick Steinhardt1-7/+7
While perfectly legal, older compiler toolchains complain when zero-initializing structs that contain nested structs with `{0}`: /home/libgit2/source/deps/reftable/stack.c:862:35: error: suggest braces around initialization of subobject [-Werror,-Wmissing-braces] struct reftable_addition empty = REFTABLE_ADDITION_INIT; ^~~~~~~~~~~~~~~~~~~~~~ /home/libgit2/source/deps/reftable/stack.c:707:33: note: expanded from macro 'REFTABLE_ADDITION_INIT' #define REFTABLE_ADDITION_INIT {0} ^ We had the discussion around whether or not we want to handle such bogus compiler errors in the past already [1]. Back then we basically decided that we do not care about such old-and-buggy compilers, so while we could fix the issue by using `{{0}}` instead this is not the preferred way to handle this in the Git codebase. We have an easier fix though: we can just drop the macro altogether and handle initialization of the struct in `reftable_stack_addition_init()`. Callers are expected to call this function already, so this change even simplifies the calling convention. [1]: https://lore.kernel.org/git/20220710081135.74964-1-sunshine@sunshineco.com/T/ Suggested-by: Carlo Arenas <carenas@gmail.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable/stack: reorder code to avoid forward declarationsPatrick Steinhardt1-188/+176
We have a couple of forward declarations in the stack-related code of the reftable library. These declarations aren't really required, but are simply caused by unfortunate ordering. Reorder the code and remove the forward declarations. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable/writer: drop Git-specific `QSORT()` macroPatrick Steinhardt1-2/+4
The reftable writer accidentally uses the Git-specific `QSORT()` macro. This macro removes the need for the caller to provide the element size, but other than that it's mostly equivalent to `qsort()`. Replace the macro accordingly to make the library usable outside of Git. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable/writer: fix type used for number of recordsPatrick Steinhardt2-10/+11
Both `reftable_writer_add_refs()` and `reftable_writer_add_logs()` accept an array of records that should be added to the new table. Callers of this function are expected to also pass the number of such records to the function to tell it how many such records it is supposed to write. But while all callers pass in a `size_t`, which is a sensible choice, the function in fact accepts an `int` as argument, which is less so. Fix this. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-29reftable: make REFTABLE_UNUSED C99 compatibleCarlo Marcelo Arenas Belón1-0/+4
Since f93b2a0424 (reftable/basics: introduce `REFTABLE_UNUSED` annotation, 2025-02-18), the reftable library was migrated to use an internal version of `UNUSED`, which unconditionally sets a GNU __attribute__ to avoid warnings function parameters that are not being used. Make the definition conditional to prevent breaking the build with non GNU compilers. Reported-by: "Randall S. Becker" <rsbecker@nexbridge.com> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-19Merge branch 'ps/reftable-read-block-perffix'Junio C Hamano3-12/+9
Performance regression in not-yet-released code has been corrected. * ps/reftable-read-block-perffix: reftable: fix perf regression when reading blocks of unwanted type
2025-05-19Merge branch 'ly/reftable-writer-leakfix'Junio C Hamano1-2/+6
Leakfix. * ly/reftable-writer-leakfix: reftable/writer: fix memory leak when `writer_index_hash()` fails reftable/writer: fix memory leak when `padded_write()` fails
2025-05-12reftable: fix perf regression when reading blocks of unwanted typePatrick Steinhardt3-12/+9
In fd888311fbc (reftable/table: move reading block into block reader, 2025-04-07), we have refactored how reftable blocks are read so that most of the logic is contained in the "block.c" subsystem itself. Most importantly, the whole logic to read the data itself is now contained in that subsystem. This change caused a significant performance regression though when reading blocks that aren't of the specific type one is searching for: Benchmark 1: update-ref: create 100k refs (revision = fd888311fbc~) Time (mean ± σ): 2.171 s ± 0.028 s [User: 1.189 s, System: 0.977 s] Range (min … max): 2.117 s … 2.206 s 10 runs Benchmark 2: update-ref: create 100k refs (revision = fd888311fbc) Time (mean ± σ): 3.418 s ± 0.030 s [User: 2.371 s, System: 1.037 s] Range (min … max): 3.377 s … 3.473 s 10 runs Summary update-ref: create 100k refs (revision = fd888311fbc~) ran 1.57 ± 0.02 times faster than update-ref: create 100k refs (revision = fd888311fbc) The root caute of the performance regression is that we changed when exactly blocks of an uninteresting type are being discarded. Previous to the refactoring in the mentioned commit we'd load the block data, read its type, notice that it's not the wanted type and discard the block. After the commit though we don't discard the block immediately, but we fully decode it only to realize that it's not the desired type. We then discard the block again, but have already performed a bunch of pointless work. Fix the regression by making `reftable_block_init()` return early in case the block is not of the desired type. This fixes the performance hit: Benchmark 1: update-ref: create 100k refs (revision = HEAD~) Time (mean ± σ): 2.712 s ± 0.018 s [User: 1.990 s, System: 0.716 s] Range (min … max): 2.682 s … 2.741 s 10 runs Benchmark 2: update-ref: create 100k refs (revision = HEAD) Time (mean ± σ): 1.670 s ± 0.012 s [User: 0.991 s, System: 0.676 s] Range (min … max): 1.652 s … 1.693 s 10 runs Summary update-ref: create 100k refs (revision = HEAD) ran 1.62 ± 0.02 times faster than update-ref: create 100k refs (revision = HEAD~) Note that the baseline performance is lower than in the original due to a couple of unrelated performance improvements that have landed since the original commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-12reftable/writer: fix memory leak when `writer_index_hash()` failsLidong Yan1-1/+3
In reftable/writer.c:writer_index_hash(), if `reftable_buf_add` failed, key allocated by `reftable_malloc` will not be insert into `obj_index_tree` thus leaks. Simple add reftable_free(key) will solve this problem. Signed-off-by: Lidong Yan <502024330056@smail.nju.edu.cn> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-12reftable/writer: fix memory leak when `padded_write()` failsLidong Yan1-1/+3
In reftable/writer.c:padded_write(), if w->writer failed, zeroed allocated in `reftable_calloc` will leak. w->writer could be `reftable_write_data` in reftable/stack.c, and could fail due to some write error. Simply add reftable_free(zeroed) will solve this problem. Signed-off-by: Lidong Yan <502024330056@smail.nju.edu.cn> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-29Merge branch 'ps/reftable-api-revamp'Junio C Hamano38-940/+1037
Overhaul of the reftable API. * ps/reftable-api-revamp: reftable/table: move printing logic into test helper reftable/constants: make block types part of the public interface reftable/table: introduce iterator for table blocks reftable/table: add `reftable_table` to the public interface reftable/block: expose a generic iterator over reftable records reftable/block: make block iterators reseekable reftable/block: store block pointer in the block iterator reftable/block: create public interface for reading blocks git-zlib: use `struct z_stream_s` instead of typedef reftable/block: rename `block_reader` to `reftable_block` reftable/block: rename `block` to `block_data` reftable/table: move reading block into block reader reftable/block: simplify how we track restart points reftable/blocksource: consolidate code into a single file reftable/reader: rename data structure to "table" reftable: fix formatting of the license header
2025-04-15Merge branch 'ps/reftable-windows-unlink-fix'Junio C Hamano1-0/+1
Portability fix. * ps/reftable-windows-unlink-fix: reftable: ignore file-in-use errors when unlink(3p) fails on Windows
2025-04-08Merge branch 'ps/reftable-sans-compat-util'Junio C Hamano15-147/+327
Make the code in reftable library less reliant on the service routines it used to borrow from Git proper, to make it easier to use by external users of the library. * ps/reftable-sans-compat-util: Makefile: skip reftable library for Coccinelle reftable: decouple from Git codebase by pulling in "compat/posix.h" git-compat-util.h: split out POSIX-emulating bits compat/mingw: split out POSIX-related bits reftable/basics: introduce `REFTABLE_UNUSED` annotation reftable/basics: stop using `SWAP()` macro reftable/stack: stop using `sleep_millisec()` reftable/system: introduce `reftable_rand()` reftable/reader: stop using `ARRAY_SIZE()` macro reftable/basics: provide wrappers for big endian conversion reftable/basics: stop using `st_mult()` in array allocators reftable: stop using `BUG()` in trivial cases reftable/record: don't `BUG()` in `reftable_record_cmp()` reftable/record: stop using `BUG()` in `reftable_record_init()` reftable/record: stop using `COPY_ARRAY()` reftable/blocksource: stop using `xmmap()` reftable/stack: stop using `write_in_full()` reftable/stack: stop using `read_in_full()`
2025-04-07reftable/table: move printing logic into test helperPatrick Steinhardt2-68/+0
The logic to print individual blocks in a table is hosted in the reftable library. This is only the case due to historical reasons though because users of the library had no interfaces to read blocks one by one. Otherwise, printing individual blocks has no place in the reftable library given that the format will not be generic in the first place. We have now grown a public interface to iterate through blocks contained in a table, and thus we can finally move the logic to print them into the test helper. Move over the logic and refactor it accordingly. Note that the iterator also trivially allows us to access index sections, which we previously didn't print at all. This omission wasn't intentional though, so start dumping those sections as well so that we can assert that indices are written as expected. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/constants: make block types part of the public interfacePatrick Steinhardt9-69/+83
Now that reftable blocks can be read individually via the public interface it becomes necessary for callers to be able to distinguish the different types of blocks. Expose the relevant constants. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/table: introduce iterator for table blocksPatrick Steinhardt2-0/+63
Introduce a new iterator that allows the caller to iterate through all blocks contained in a table. This gives users more fine-grained control over how exactly those blocks are being read and exposes information to callers that was previously inaccessible. This iterator will be required by a future patch series that adds consistency checks for the reftable backend. In addition to that though we will also reimplement `reftable_table_print_blocks()` on top of this new iterator in a subsequent commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/table: add `reftable_table` to the public interfacePatrick Steinhardt2-34/+31
The `reftable_table` interface is an internal implementation detail that callers have no access to. Having direct access to this structure is important though for a subsequent patch series that will implement consistency checks for the reftable backend. Move the structure into "reftable-table.h" so that it part of the public interface. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/block: expose a generic iterator over reftable recordsPatrick Steinhardt3-1/+62
Expose a generic iterator over reftable records and expose it via the public interface. Together with an upcoming iterator for reftable blocks contained in a table this will allow users to trivially iterate through blocks and their respective records individually. This functionality will be used to implement consistency checks for the reftable backend, which requires more fine-grained control over how we read data. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/block: make block iterators reseekablePatrick Steinhardt4-20/+37
Refactor the block iterators so that initialization and seeking are different from one another. This makes the iterator trivially reseekable by storing the pointer to the block at initialization time, which we can then reuse on every seek. This refactoring prepares the code for exposing a `reftable_iterator` interface for blocks in a subsequent commit. Callsites are adjusted accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/block: store block pointer in the block iteratorPatrick Steinhardt2-17/+9
The block iterator requires access to a bunch of data from the underlying `reftable_block` that it is iterating over. This data is stored by copying over relevant data into a separate set of variables. This has multiple downsides: - We require more storage space than necessary. This is more of a theoretical issue as we shouldn't ever have many blocks. - We have to perform more bookkeeping, and the variable names are inconsistent across the two data structures. This can lead to some confusion. - The lifetime of the block iterator is tied to the block anyway, but we hide that a bit by only storing pointers pointing into the block. There isn't really any good reason why we rip out parts of the block instead of storing a pointer to the block itself. Refactor the code to do so. Despite being simpler, it also allows us to decouple the lifetime of the block iterator from seeking in a subsequent commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/block: create public interface for reading blocksPatrick Steinhardt4-54/+78
While users of the reftable library wouldn't generally require access to individual blocks in a reftable table, there are valid usecases where one may require low-level access to them. One such upcoming usecase in the Git codebase is to implement consistency checks for the reftable library where we want to verify each block individually. Create a public interface for reading blocks. The interface isn't yet complete and lacks e.g. a way to read individual records from a block. Such missing functionality will be backfilled in subsequent commits. Note that this change also requires us to expose `reftable_buf`, which is used by the `reftable_block_first_key()` function. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07git-zlib: use `struct z_stream_s` instead of typedefPatrick Steinhardt1-4/+2
Throughout the Git codebase we're using the typedeffed version of `z_stream`, which maps to `struct z_stream_s`. By using a typedef instead of the struct it becomes somewhat harder to predeclare the symbol so that headers depending on the struct can do so without having to pull in "zlib-compat.h". We don't yet have users that would really care about this: the only users that declare `z_stream` as a pointer are in "reftable/block.h", which is a header that is internal to the reftable library. But in the next step we're going to expose the `struct reftable_block` publicly, and that struct does contain a pointer to `z_stream`. And as the public header shouldn't depend on "reftable/system.h", which is an internal implementation detail, we won't have the typedef for `z_stream` readily available. Prepare for this change by using `struct z_stream_s` throughout our code base. In case zlib-ng is used we use a define to map from `z_stream_s` to `zng_stream_s`. Drop the pre-declaration of `struct z_stream` while at it. This struct does not exist in the first place, and the declaration wasn't needed because "reftable/block.h" already includes "reftable/basics.h" which transitively includes "reftable/system.h" and thus "git-zlib.h". Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/block: rename `block_reader` to `reftable_block`Patrick Steinhardt6-115/+121
The `block_reader` structure is used to access parsed data of a reftable block. The structure is currently treated as an internal implementation detail and not exposed via our public interfaces. The functionality provided by the structure is useful to external users of the reftable library though, for example when implementing consistency checks that need to scan through the blocks manually. Rename the structure to `reftable_block` now that the name has been made available in the preceding commit. This name is in line with the naming schema used for other data structures like `reftable_table` in that it describes the underlying entity that it provides access to. The new data structure isn't yet exposed via the public interface, which is left for a subsequent commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/block: rename `block` to `block_data`Patrick Steinhardt7-68/+68
The `reftable_block` structure associates a byte slice with a block source. As such it only holds the data of a reftable block without actually encoding any of the details for how to access that data. Rename the structure to instead be called `reftable_block_data`. Besides clarifying that this really only holds data, it also allows us to rename the `reftable_block_reader` to `reftable_block` in the next commit, as this is the structure that actually encapsulates access to the reftable blocks. Rename the `struct reftable_block_reader::block` member accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/table: move reading block into block readerPatrick Steinhardt3-93/+67
The logic to read blocks from a reftable is scattered across both the table and the block subsystems. Besides causing somewhat fuzzy responsibilities, it also means that we have to awkwardly pass around the ownership of blocks between the subsystems. Refactor the code so that we stop passing the block when initializing a reader, but instead by passing in the block source plus the offset at which we're supposed to read a block. Like this, the ownership of the block itself doesn't need to get handed over as the block reader is the one owning the block right from the start. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/block: simplify how we track restart pointsPatrick Steinhardt3-17/+18
Restart points record the location of reftable records that do not use prefix compression and are used to perform a binary search inside of a block. These restart points are encoded at the end of a block, between the record data and the footer of a table. The block structure contains three different variables related to these restart points: - The block length contains the length of the reftable block up to the restart points. - The restart count contains the number of restart points contained in the block. - The restart bytes variable tracks where the restart point data begins. Tracking all three of these variables is unnecessary though as the data can be derived from one another: the block length without restart points is the exact same as the offset of the restart count data, which we already track via the `restart_bytes` data. Refactor the code so that we track the location of restart bytes not as a pointer, but instead as an offset. This allows us to trivially get rid of the `block_len` variable as described above. This avoids having the confusing `block_len` variable and allows us to do less bookkeeping overall. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/blocksource: consolidate code into a single filePatrick Steinhardt8-56/+74
The code that implements block sources is distributed across a couple of files. Consolidate all of it into "reftable/blocksource.c" and its accompanying header so that it is easier to locate and more self contained. While at it, rename some of the functions to have properly scoped names. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable/reader: rename data structure to "table"Patrick Steinhardt11-325/+325
The `struct reftable_reader` subsystem encapsulates a table that has been read from the disk. As such, the current name of that structure is somewhat hard to understand as it only talks about the fact that we read something from disk, without really giving an indicator _what_ that is. Furthermore, this naming schema doesn't really fit well into how the other structures are named: `reftable_merged_table`, `reftable_stack`, `reftable_block` and `reftable_record` are all named after what they encapsulate. Rename the subsystem to `reftable_table`, which directly gives a hint that the data structure is about handling the individual tables part of the stack. While this change results in a lot of churn, it prepares for us exposing the APIs to third-party callers now that the reftable library is a standalone library that can be linked against by other projects. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07reftable: fix formatting of the license headerPatrick Steinhardt34-199/+199
The license headers used across the reftable library doesn't follow our typical coding style for multi-line comments. Fix it. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-01Merge branch 'ps/reftable-sans-compat-util' into ps/reftable-api-revampJunio C Hamano15-147/+327
* ps/reftable-sans-compat-util: Makefile: skip reftable library for Coccinelle reftable: decouple from Git codebase by pulling in "compat/posix.h" git-compat-util.h: split out POSIX-emulating bits compat/mingw: split out POSIX-related bits reftable/basics: introduce `REFTABLE_UNUSED` annotation reftable/basics: stop using `SWAP()` macro reftable/stack: stop using `sleep_millisec()` reftable/system: introduce `reftable_rand()` reftable/reader: stop using `ARRAY_SIZE()` macro reftable/basics: provide wrappers for big endian conversion reftable/basics: stop using `st_mult()` in array allocators reftable: stop using `BUG()` in trivial cases reftable/record: don't `BUG()` in `reftable_record_cmp()` reftable/record: stop using `BUG()` in `reftable_record_init()` reftable/record: stop using `COPY_ARRAY()` reftable/blocksource: stop using `xmmap()` reftable/stack: stop using `write_in_full()` reftable/stack: stop using `read_in_full()`
2025-03-21reftable: adapt write_object_record() to propagate block_writer_add() errorsMeet Soni1-0/+19
Previously, write_object_record() would flush the current block and retry appending the record whenever block_writer_add() returned any nonzero error. This forced an assumption that every failure meant the block was full, even when errors such as memory allocation or I/O failures occurred. Update the write_object_record() to inspect the error code returned by block_writer_add() and flush and reinitialize the writer iff the error is REFTABLE_ENTRY_TOO_BIG_ERROR. For any other error, immediately propagate it. If the flush and reinitialization still fail with REFTABLE_ENTRY_TOO_BIG_ERROR, reset the record's offset length to zero before a final attempt. All call sites now handle various error codes returned by block_writer_add(). Signed-off-by: Meet Soni <meetsoni3017@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-21reftable: adapt writer_add_record() to propagate block_writer_add() errorsMeet Soni1-10/+5
Previously, writer_add_record() would flush the current block and retry appending the record whenever block_writer_add() returned any nonzero error. This forced an assumption that every failure meant the block was full, even when errors such as memory allocation or I/O failures occurred. Update the writer_add_record() to inspect the error code returned by block_writer_add() and only flush and reinitialize the writer when the error is REFTABLE_ENTRY_TOO_BIG_ERROR. For any other error, immediately propagate it. Signed-off-by: Meet Soni <meetsoni3017@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-21reftable: propagate specific error codes in block_writer_add()Meet Soni3-36/+32
Previously, functions block_writer_add() and related functions returned -1 when the record did not fit, forcing the caller to assume that any failure meant the entry was too big. Replace these generic -1 returns with defined error codes. This prepares the codebase for finer-grained error handling so that callers can distinguish between a block-full condition and other errors. Signed-off-by: Meet Soni <meetsoni3017@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-04reftable: release name on reftable_reader_new() errorRené Scharfe1-0/+2
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>
2025-02-18reftable: ignore file-in-use errors when unlink(3p) fails on WindowsPatrick Steinhardt1-0/+1
Unlinking a file may fail on Windows systems when the file is still held open by another process. This is incompatible with POSIX semantics and by extension with Git's assumed semantics when unlinking files, which is that files can be unlinked regardless of whether they are still open or not. To counteract this incompatibility, we have some custom error handling in the `mingw_unlink()` wrapper that first retries the deletion with some delay, and then asks the user whether we should continue to retry. While this logic might be sensible in many callsites throughout Git, it is less when used in the reftable library. We only use unlink(3) there to delete tables which aren't referenced anymore, and the code is very aware of the limitations on Windows. As such, all calls to unlink(3p) don't perform any error checking at all and are fine with the call failing. Instead, the library provides the `reftable_stack_clean()` function, which Git knows to execute in git-pack-refs(1) after compacting a stack. The effect of this function is that all stale tables will eventually get deleted once they aren't kept open anymore. So while we're fine with unlink(3p) failing, the Windows-emulation of that function will still perform several sleeps and ultimately end up asking the user: $ git pack-refs Unlink of file 'C:/temp/jgittest/jgit/.git/reftable/0x000000000002-0x000000000004-50486d0e.ref' failed. Should I try again? (y/n) n Unlink of file 'C:/temp/jgittest/jgit/.git/reftable/0x000000000002-0x000000000004-50486d0e.ref' failed. Should I try again? (y/n) n Unlink of file 'C:/temp/jgittest/jgit/.git/reftable/0x000000000002-0x000000000004-50486d0e.ref' failed. Should I try again? (y/n) n It even asks multiple times, which is doubly annoying and puzzling to the user: 1. It asks when trying to delete the old file after having written the compacted stack. 2. It asks when reloading the stack, where it will try to unlink now-unreferenced tables. 3. It asks when calling `reftable_stack_clean()`, where it will try to unlink now-stale tables. Fix the issue by making it possible to disable this behaviour with a preprocessor define. As "git-compat-util.h" is only included from "system.h", and given that "system.h" is only ever included by headers and code that are internal to the reftable library, we can set that macro in this header without impacting anything else but the reftable library. Reported-by: Christian Reich <Zottelbart@t-online.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable: decouple from Git codebase by pulling in "compat/posix.h"Patrick Steinhardt2-1/+3
The reftable library includes "git-compat-util.h" in order to get a POSIX-like programming environment that papers over various differences between platforms. The header also brings with it a couple of helpers specific to the Git codebase though, and over time we have started to use these helpers in the reftable library, as well. This makes it very hard to use the reftable library as a standalone library without the rest of the Git codebase, so other libraries like e.g. libgit2 cannot easily use it. But now that we have removed all calls to Git-specific functionality and have split out "compat/posix.h" as a separate header we can address this. Stop including "git-compat-util.h" and instead include "compat/posix.h" to finalize the decoupling of the reftable library from the rest of the Git codebase. The only bits which remain specific to Git are "system.h" and "system.c", which projects will have to provide. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable/basics: introduce `REFTABLE_UNUSED` annotationPatrick Steinhardt5-22/+24
Introduce the `REFTABLE_UNUSED` annotation and replace all existing users of `UNUSED` in the reftable library to use the new macro instead. Note that we unconditionally define `MAYBE_UNUSED` in the exact same way, so doing so unconditionally for `REFTABLE_UNUSED` should be fine, too. Suggested-by: Toon Claes <toon@iotcl.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable/basics: stop using `SWAP()` macroPatrick Steinhardt4-11/+20
Stop using `SWAP()` macro in favor of an open-coded variant of it. Note that this also requires us to open-code the build assert that `SWAP()` itself uses to verify that the size of both variables matches. This is done to reduce our dependency on the Git codebase. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable/stack: stop using `sleep_millisec()`Patrick Steinhardt1-1/+1
Refactor our use of `sleep_millisec()` by open-coding it with poll(3p), which is the current implementation of this function. Ideally, we'd use a more direct way to sleep, but there is no equivalent to sleep(3p) that would accept milliseconds as input. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable/system: introduce `reftable_rand()`Patrick Steinhardt3-2/+13
Introduce a new system-level `reftable_rand()` function that generates a single unsigned integer for us. The implementation of this function is to be provided by the calling codebase, which allows us to more easily hook into pre-seeded random number generators. Adapt the two callsites where we generated random data. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable/reader: stop using `ARRAY_SIZE()` macroPatrick Steinhardt1-1/+1
We have a single user of the `ARRAY_SIZE()` macro in the reftable reader. Drop its use to reduce our dependence on the Git codebase. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable/basics: provide wrappers for big endian conversionPatrick Steinhardt6-53/+104
We're using a mixture of big endian conversion functions provided by both the reftable library, but also by the Git codebase. Refactor the code so that we exclusively use reftable-provided wrappers in order to untangle us from the Git codebase. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable/basics: stop using `st_mult()` in array allocatorsPatrick Steinhardt1-4/+32
We're using `st_mult()` as part of our macro helpers that allocate arrays. This is bad due two two reasons: - `st_mult()` causes us to die in case the multiplication overflows. - `st_mult()` ties us to the Git codebase. Refactor the code to instead detect overflows manually and return an error in such cases. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable: stop using `BUG()` in trivial casesPatrick Steinhardt3-9/+3
Stop using `BUG()` in the remaining trivial cases that we still have in the reftable library. Instead of aborting the program, we'll now bubble up a `REFTABLE_API_ERROR` to indicate misuse of the calling conventions. Note that in both `reftable_reader_{inc,dec}ref()` we simply stop calling `BUG()` altogether. The only situation where the counter should be zero is when the structure has already been free'd anyway, so we would run into undefined behaviour regardless of whether we try to abort the program or not. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>