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2021-10-25Merge branch 'jt/no-abuse-alternate-odb-for-submodules'Libravatar Junio C Hamano1-2/+9
Follow through the work to use the repo interface to access submodule objects in-process, instead of abusing the alternate object database interface. * jt/no-abuse-alternate-odb-for-submodules: submodule: trace adding submodule ODB as alternate submodule: pass repo to check_has_commit() object-file: only register submodule ODB if needed merge-{ort,recursive}: remove add_submodule_odb() refs: peeling non-the_repository iterators is BUG refs: teach arbitrary repo support to iterators refs: plumb repo into ref stores
2021-10-11Merge branch 'jk/ref-paranoia'Libravatar Junio C Hamano1-21/+35
The ref iteration code used to optionally allow dangling refs to be shown, which has been tightened up. * jk/ref-paranoia: refs: drop "broken" flag from for_each_fullref_in() ref-filter: drop broken-ref code entirely ref-filter: stop setting FILTER_REFS_INCLUDE_BROKEN repack, prune: drop GIT_REF_PARANOIA settings refs: turn on GIT_REF_PARANOIA by default refs: omit dangling symrefs when using GIT_REF_PARANOIA refs: add DO_FOR_EACH_OMIT_DANGLING_SYMREFS flag refs-internal.h: reorganize DO_FOR_EACH_* flag documentation refs-internal.h: move DO_FOR_EACH_* flags next to each other t5312: be more assertive about command failure t5312: test non-destructive repack t5312: create bogus ref as necessary t5312: drop "verbose" helper t5600: provide detached HEAD for corruption failures t5516: don't use HEAD ref for invalid ref-deletion tests t7900: clean up some more broken refs
2021-10-08refs: teach arbitrary repo support to iteratorsLibravatar Jonathan Tan1-0/+1
Note that should_pack_ref() is called when writing refs, which is only supported for the_repository, hence the_repository is hardcoded there. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-08refs: plumb repo into ref storesLibravatar Jonathan Tan1-2/+8
In preparation for the next 2 patches that adds (partial) support for arbitrary repositories to ref iterators, plumb a repository into all ref stores. There are no changes to program logic. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27refs: add DO_FOR_EACH_OMIT_DANGLING_SYMREFS flagLibravatar Jeff King1-0/+6
When the DO_FOR_EACH_INCLUDE_BROKEN flag is used, we include both actual corrupt refs (illegal names, missing objects), but also symrefs that point to nothing. This latter is not really a corruption, but just something that may happen normally. For example, the symref at refs/remotes/origin/HEAD may point to a tracking branch which is later deleted. (The local HEAD may also be unborn, of course, but we do not access it through ref iteration). Most callers of for_each_ref() etc, do not care. They don't pass INCLUDE_BROKEN, so don't see it at all. But for those which do pass it, this somewhat-normal state causes extra warnings (e.g., from for-each-ref) or even aborts operations (destructive repacks with GIT_REF_PARANOIA set). This patch just introduces the flag and the mechanism; there are no callers yet (and hence no tests). Two things to note on the implementation: - we actually skip any symref that does not resolve to a ref. This includes ones which point to an invalidly-named ref. You could argue this is a more serious breakage than simple dangling. But the overall effect is the same (we could not follow the symref), as well as the impact on things like REF_PARANOIA (either way, a symref we can't follow won't impact reachability, because we'll see the ref itself during iteration). The underlying resolution function doesn't distinguish these two cases (they both get REF_ISBROKEN). - we change the iterator in refs/files-backend.c where we check INCLUDE_BROKEN. There's a matching spot in refs/packed-backend.c, but we don't know need to do anything there. The packed backend does not support symrefs at all. The resulting set of flags might be a bit easier to follow if we broke this down into "INCLUDE_CORRUPT_REFS" and "INCLUDE_DANGLING_SYMREFS". But there are a few reasons not do so: - adding a new OMIT_DANGLING_SYMREFS flag lets us leave existing callers intact, without changing their behavior (and some of them really do want to see the dangling symrefs; e.g., t5505 has a test which expects us to report when a symref becomes dangling) - they're not actually independent. You cannot say "include dangling symrefs" without also including refs whose objects are not reachable, because dangling symrefs by definition do not have an object. We could tweak the implementation to distinguish this, but in practice nobody wants to ask for that. Adding the OMIT flag keeps the implementation simple and makes sure we don't regress the current behavior. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27refs-internal.h: reorganize DO_FOR_EACH_* flag documentationLibravatar Jeff King1-19/+27
The documentation for the DO_FOR_EACH_* flags is sprinkled over the refs-internal.h file. We define the two flags in one spot, and then describe them in more detail far away from there, in the definitions of refs_ref_iterator_begin() and ref_iterator_advance_fn(). Let's try to organize this a bit better: - convert the #defines to an enum. This makes it clear that they are related, and that the enum shows the complete set of flags. - combine all descriptions for each flag in a single spot, next to the flag's definition - use the enum rather than a bare int for functions which take the flags. This helps readers realize which flags can be used. - clarify the mention of flags for ref_iterator_advance_fn(). It does not take flags itself, but is meant to depend on ones set up earlier. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27refs-internal.h: move DO_FOR_EACH_* flags next to each otherLibravatar Jeff King1-8/+8
There are currently two DO_FOR_EACH_* flags, which must not have their bits overlap. Yet they're defined hundreds of lines apart. Let's move them next to each other to make it clear that they are related and are a complete set (which matters if you are adding a new flag and would like to know what the next available bit is). Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-25refs: make errno output explicit for read_raw_ref_fnLibravatar Han-Wen Nienhuys1-8/+12
This makes it explicit how alternative ref backends should report errors in read_raw_ref_fn. read_raw_ref_fn needs to supply a credible errno for a number of cases. These are primarily: 1) The files backend calls read_raw_ref from lock_raw_ref, and uses the resulting error codes to create/remove directories as needed. 2) ENOENT should be translated in a zero OID, optionally with REF_ISBROKEN set, returning the last successfully resolved symref. This is necessary so read_raw_ref("HEAD") on an empty repo returns refs/heads/main (or the default branch du-jour), and we know on which branch to create the first commit. Make this information flow explicit by adding a failure_errno to the signature of read_raw_ref. All errnos from the files backend are still propagated unchanged, even though inspection suggests only ENOTDIR, EISDIR and ENOENT are relevant. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-25refs: remove EINVAL errno output from specification of read_raw_ref_fnLibravatar Han-Wen Nienhuys1-3/+3
This commit does not change code; it documents the fact that an alternate ref backend does not need to return EINVAL from read_raw_ref_fn to function properly. This is correct, because refs_read_raw_ref is only called from; * resolve_ref_unsafe(), which does not care for the EINVAL errno result. * refs_verify_refname_available(), which does not inspect errno. * files-backend.c, where errno is overwritten on failure. * packed-backend.c (is_packed_transaction_needed), which calls it for the packed ref backend, which never emits EINVAL. A grep for EINVAL */*c reveals that no code checks errno against EINVAL after reading references. In addition, the refs.h file does not mention errno at all. A grep over resolve_ref_unsafe() turned up the following callers that inspect errno: * sequencer.c::print_commit_summary, which uses it for die_errno * lock_ref_oid_basic(), which only treats EISDIR and ENOTDIR specially. The files ref backend does use EINVAL. The files backend does not call into the generic API (refs_read_raw), but into the files-specific function (files_read_raw_ref), which we are not changing in this commit. As the errno sideband is unintuitive and error-prone, remove EINVAL value, as a step towards getting rid of the errno sideband altogether. Spotted by Ævar Arnfjörð Bjarmason <avarab@gmail.com>. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-25refs API: remove OID argument to reflog_expire()Libravatar Ævar Arnfjörð Bjarmason1-1/+1
Since the the preceding commit the "oid" parameter to reflog_expire() is always NULL, but it was not cleaned up to reduce the size of the diff. Let's do that subsequent API and documentation cleanup now. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-20refs: make explicit that ref_iterator_peel returns booleanLibravatar Han-Wen Nienhuys1-0/+3
Use -1 as error return value throughout. This removes spurious differences in the GIT_TRACE_REFS output, depending on the ref storage backend active. Before, the cached ref_iterator (but only that iterator!) would return peel_object() output directly. No callers relied on the peel_status values beyond success/failure. All calls to these functions go through peel_iterated_oid(), which returns peel_object() as a fallback, but also squashing the error values. The iteration interface already passes REF_ISSYMREF and REF_ISBROKEN through the flags argument, so the additional error values in enum peel_status provide no value. The ref iteration interface provides a separate peel() function because certain formats (eg. packed-refs and reftable) can store the peeled object next to the tag SHA1. Passing the peeled SHA1 as an optional argument to each_ref_fn maps more naturally to the implementation of ref databases. Changing the code in this way is left for a future refactoring. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-22Merge branch 'hn/refs-trace-backend'Libravatar Junio C Hamano1-0/+5
Developer support. * hn/refs-trace-backend: refs: add GIT_TRACE_REFS debugging mechanism
2020-09-09refs: add GIT_TRACE_REFS debugging mechanismLibravatar Han-Wen Nienhuys1-0/+5
When set in the environment, GIT_TRACE_REFS makes git print operations and results as they flow through the ref storage backend. This helps debug discrepancies between different ref backends. Example: $ GIT_TRACE_REFS="1" ./git branch 15:42:09.769631 refs/debug.c:26 ref_store for .git 15:42:09.769681 refs/debug.c:249 read_raw_ref: HEAD: 0000000000000000000000000000000000000000 (=> refs/heads/ref-debug) type 1: 0 15:42:09.769695 refs/debug.c:249 read_raw_ref: refs/heads/ref-debug: 3a238e539bcdfe3f9eb5010fd218640c1b499f7a (=> refs/heads/ref-debug) type 0: 0 15:42:09.770282 refs/debug.c:233 ref_iterator_begin: refs/heads/ (0x1) 15:42:09.770290 refs/debug.c:189 iterator_advance: refs/heads/b4 (0) 15:42:09.770295 refs/debug.c:189 iterator_advance: refs/heads/branch3 (0) Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-08refs: move REF_LOG_ONLY to refs-internal.hLibravatar Han-Wen Nienhuys1-0/+7
REF_LOG_ONLY is used in the transaction preparation: if a symref is involved in a transaction, the referent of the symref should be updated, and the symref itself should only be updated in the reflog. Other ref backends will need to duplicate this logic too, so move it to a central place. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-19refs: move gitdir into base ref_storeLibravatar Han-Wen Nienhuys1-0/+3
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-19refs: fix comment about submodule ref_storesLibravatar Han-Wen Nienhuys1-1/+1
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-19refs: split off reading loose ref data in separate functionLibravatar Han-Wen Nienhuys1-0/+6
This prepares for handling FETCH_HEAD (which is not a regular ref) separately from the ref backend. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-10reflog: cleanse messages in the refs.c layerLibravatar Junio C Hamano1-6/+0
Regarding reflog messages: - We expect that a reflog message consists of a single line. The file format used by the files backend may add a LF after the message as a delimiter, and output by commands like "git log -g" may complete such an incomplete line by adding a LF at the end, but philosophically, the terminating LF is not a part of the message. - We however allow callers of refs API to supply a random sequence of NUL terminated bytes. We cleanse caller-supplied message by squashing a run of whitespaces into a SP, and by trimming trailing whitespace, before storing the message. This is how we tolerate, instead of erring out, a message with LF in it (be it at the end, in the middle, or both). Currently, the cleansing of the reflog message is done by the files backend, before the log is written out. This is sufficient with the current code, as that is the only backend that writes reflogs. But new backends can be added that write reflogs, and we'd want the resulting log message we would read out of "log -g" the same no matter what backend is used, and moving the code to do so to the generic layer is a way to do so. An added benefit is that the "cleansing" function could be updated later, independent from individual backends, to e.g. allow multi-line log messages if we wanted to, and when that happens, it would help a lot to ensure we covered all bases if the cleansing function (which would be updated) is called from the generic layer. Side note: I am not interested in supporting multi-line reflog messages right at the moment (nobody is asking for it), but I envision that instead of the "squash a run of whitespaces into a SP and rtrim" cleansing, we can %urlencode problematic bytes in the message *AND* append a SP at the end, when a new version of Git that supports multi-line and/or verbatim reflog messages writes a reflog record. The reading side can detect the presense of SP at the end (which should have been rtrimmed out if it were written by existing versions of Git) as a signal that decoding %urlencode recovers the original reflog message. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-20refs: improve documentation for ref iteratorLibravatar Han-Wen Nienhuys1-3/+15
Document some of the flag options in refs_ref_iterator_begin, and explain how ref_iterator_advance_fn should handle them. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-10Fix spelling errors in code commentsLibravatar Elijah Newren1-1/+1
Reported-by: Jens Schleusener <Jens.Schleusener@fossies.org> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-16Merge branch 'rj/header-check'Libravatar Junio C Hamano1-0/+4
Header files clean-up. * rj/header-check: delta-islands.h: add missing forward declarations (hdr-check) midx.h: add missing forward declarations (hdr-check) refs/refs-internal.h: add missing declarations (hdr-check) refs/packed-backend.h: add missing declaration (hdr-check) refs/ref-cache.h: add missing declarations (hdr-check) ewah/ewok_rlw.h: add missing include (hdr-check) json-writer.h: add missing include (hdr-check) Makefile: add a hdr-check target
2018-10-16Merge branch 'tq/refs-internal-comment-fix'Libravatar Junio C Hamano1-1/+1
Fix for typo in a sample code in comment. * tq/refs-internal-comment-fix: refs: docstring typo
2018-09-20refs/refs-internal.h: add missing declarations (hdr-check)Libravatar Ramsay Jones1-0/+4
Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17refs: docstring typoLibravatar Tao Qingyun1-1/+1
Signed-off-by: Tao Qingyun <taoqy@ls-a.me> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-21refs.c: migrate internal ref iteration to pass thru repository argumentLibravatar Stefan Beller1-2/+3
In 60ce76d3581 (refs: add repository argument to for_each_replace_ref, 2018-04-11) and 0d296c57aec (refs: allow for_each_replace_ref to handle arbitrary repositories, 2018-04-11), for_each_replace_ref learned how to iterate over refs by a given arbitrary repository. New attempts in the object store conversion have shown that it is useful to have the repository handle available that the refs iteration is currently iterating over. To achieve this goal we will need to add a repository argument to each_ref_fn in refs.h. However as many callers rely on the signature such a patch would be too large. So convert the internals of the ref subsystem first to pass through a repository argument without exposing the change to the user. Assume the_repository for the passed through repository, although it is not used anywhere yet. Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-24Merge branch 'bp/log-ref-write-fd-with-strbuf'Libravatar Junio C Hamano1-4/+3
Code clean-up. * bp/log-ref-write-fd-with-strbuf: convert log_ref_write_fd() to use strbuf
2018-07-10convert log_ref_write_fd() to use strbufLibravatar Ben Peart1-4/+3
Since we don't care about how many bytes were written, simplify the return value logic. log_ref_write_fd() was written long before strbuf was fleshed out. Remove the old manual buffer management code and replace it with strbuf(). Also update copy_reflog_msg() which is called only by log_ref_write_fd() to use strbuf as it keeps things consistent. Signed-off-by: Ben Peart <Ben.Peart@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-09fixup! refs/refs-internal.h: avoid forward declaration of an enumLibravatar Junio C Hamano1-1/+1
2018-07-09refs/refs-internal.h: avoid forward declaration of an enumLibravatar Beat Bolli1-0/+2
Include iterator.h to define enum iterator_selection. Signed-off-by: Beat Bolli <dev+git@drbeat.li> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06refs: update some more docs to use "oid" rather than "sha1"Libravatar Michael Haggerty1-9/+9
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06refs: rename constant `REF_NODEREF` to `REF_NO_DEREF`Libravatar Michael Haggerty1-2/+2
Even after working with this code for years, I still see this constant name as "ref node ref". Rename it to make it's meaning clearer. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06refs: tidy up and adjust visibility of the `ref_update` flagsLibravatar Michael Haggerty1-52/+15
The constants used for `ref_update::flags` were rather disorganized: * The definitions in `refs.h` were not close to the functions that used them. * Maybe constants were defined in `refs-internal.h`, making them visible to the whole refs module, when in fact they only made sense for the files backend. * Their documentation wasn't very consistent and partly still referred to sha1s rather than oids. * The numerical values followed no rational scheme Fix all of these problems. The main functional improvement is that some constants' visibility is now limited to `files-backend.c`. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16refs: convert read_raw_ref backends to struct object_idLibravatar brian m. carlson1-5/+5
Convert the unsigned char * parameter to struct object_id * for files_read_raw_ref and packed_read_raw_ref. Update the documentation. Switch from using get_sha1_hex and a hard-coded 40 to using parse_oid_hex. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16refs: convert peel_object to struct object_idLibravatar brian m. carlson1-2/+2
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16refs: convert reflog_expire parameter to struct object_idLibravatar brian m. carlson1-1/+1
reflog_expire already used struct object_id internally, but it did not take it as a parameter. Adjust the parameter (and the callers) to pass a pointer to struct object_id instead of a pointer to unsigned char. Remove the temporary inserted earlier as it is no longer required. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16refs: update ref transactions to use struct object_idLibravatar brian m. carlson1-2/+2
Update the ref transaction code to use struct object_id. Remove one NULL pointer check which was previously inserted around a dereference; since we now pass a pointer to struct object_id directly through, the code we're calling handles this for us. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-03Merge branch 'mh/mmap-packed-refs'Libravatar Junio C Hamano1-7/+19
Operations that do not touch (majority of) packed refs have been optimized by making accesses to packed-refs file lazy; we no longer pre-parse everything, and an access to a single ref in the packed-refs does not touch majority of irrelevant refs, either. * mh/mmap-packed-refs: (21 commits) packed-backend.c: rename a bunch of things and update comments mmapped_ref_iterator: inline into `packed_ref_iterator` ref_cache: remove support for storing peeled values packed_ref_store: get rid of the `ref_cache` entirely ref_store: implement `refs_peel_ref()` generically packed_read_raw_ref(): read the reference from the mmapped buffer packed_ref_iterator_begin(): iterate using `mmapped_ref_iterator` read_packed_refs(): ensure that references are ordered when read packed_ref_cache: keep the `packed-refs` file mmapped if possible packed-backend.c: reorder some definitions mmapped_ref_iterator_advance(): no peeled value for broken refs mmapped_ref_iterator: add iterator over a packed-refs file packed_ref_cache: remember the file-wide peeling state read_packed_refs(): read references with minimal copying read_packed_refs(): make parsing of the header line more robust read_packed_refs(): only check for a header at the top of the file read_packed_refs(): use mmap to read the `packed-refs` file die_unterminated_line(), die_invalid_line(): new functions packed_ref_cache: add a backlink to the associated `packed_ref_store` prefix_ref_iterator: break when we leave the prefix ...
2017-10-03Merge branch 'sd/branch-copy'Libravatar Junio C Hamano1-0/+4
"git branch" learned "-c/-C" to create a new branch by copying an existing one. * sd/branch-copy: branch: fix "copy" to never touch HEAD branch: add a --copy (-c) option to go with --move (-m) branch: add test for -m renaming multiple config sections config: create a function to format section headers
2017-09-25ref_store: implement `refs_peel_ref()` genericallyLibravatar Michael Haggerty1-3/+0
We're about to stop storing packed refs in a `ref_cache`. That means that the only way we have left to optimize `peel_ref()` is by checking whether the reference being peeled is the one currently being iterated over (in `current_ref_iter`), and if so, using `ref_iterator_peel()`. But this can be done generically; it doesn't have to be implemented per-backend. So implement `refs_peel_ref()` in `refs.c` and remove the `peel_ref()` method from the refs API. This removes the last callers of a couple of functions, so delete them. More cleanup to come... Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-14ref_iterator: keep track of whether the iterator output is orderedLibravatar Michael Haggerty1-4/+19
References are iterated over in order by refname, but reflogs are not. Some consumers of reference iteration care about the difference. Teach each `ref_iterator` to keep track of whether its output is ordered. `overlay_ref_iterator` is one of the picky consumers. Add a sanity check in `overlay_ref_iterator_begin()` to verify that its inputs are ordered. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09struct ref_transaction: add a place for backends to store dataLibravatar Michael Haggerty1-0/+1
`packed_ref_store` is going to want to store some transaction-wide data, so make a place for it. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-26Merge branch 'mh/ref-lock-entry'Libravatar Junio C Hamano1-0/+6
The code to acquire a lock on a reference (e.g. while accepting a push from a client) used to immediately fail when the reference is already locked---now it waits for a very short while and retries, which can make it succeed if the lock holder was holding it during a read-only operation. * mh/ref-lock-entry: refs: retry acquiring reference locks for 100ms
2017-08-23refs: retry acquiring reference locks for 100msLibravatar Michael Haggerty1-0/+6
The philosophy of reference locking has been, "if another process is changing a reference, then whatever I'm trying to do to it will probably fail anyway because my old-SHA-1 value is probably no longer current". But this argument falls down if the other process has locked the reference to do something that doesn't actually change the value of the reference, such as `pack-refs` or `reflog expire`. There actually *is* a decent chance that a planned reference update will still be able to go through after the other process has released the lock. So when trying to lock an individual reference (e.g., when creating "refs/heads/master.lock"), if it is already locked, then retry the lock acquisition for approximately 100 ms before giving up. This should eliminate some unnecessary lock conflicts without wasting a lot of time. Add a configuration setting, `core.filesRefLockTimeout`, to allow this setting to be tweaked. Note: the function `get_files_ref_lock_timeout_ms()` cannot be private to the files backend because it is also used by `write_pseudoref()` and `delete_pseudoref()`, which are defined in `refs.c` so that they can be used by other reference backends. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23packed_ref_store: make class into a subclass of `ref_store`Libravatar Michael Haggerty1-0/+1
Add the infrastructure to make `packed_ref_store` implement `ref_store`, at least formally (few of the methods are actually implemented yet). Change the functions in its interface to take `ref_store *` arguments. Change `files_ref_store` to store a pointer to `ref_store *` and to call functions via the virtual `ref_store` interface where possible. This also means that a few `packed_ref_store` functions can become static. This is a work in progress. Some more `ref_store` methods will soon be implemented (e.g., those having to do with reference transactions). But some of them will never be implemented (e.g., those having to do with symrefs or reflogs). Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23packed-backend: new module for handling packed referencesLibravatar Michael Haggerty1-0/+9
Now that the interface between `files_ref_store` and `packed_ref_store` is relatively narrow, move the latter into a new module, "refs/packed-backend.h" and "refs/packed-backend.c". It still doesn't quite implement the `ref_store` interface, but it will soon. This commit moves code around and adjusts its visibility, but doesn't change anything. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-18branch: add a --copy (-c) option to go with --move (-m)Libravatar Sahil Dua1-0/+4
Add the ability to --copy a branch and its reflog and configuration, this uses the same underlying machinery as the --move (-m) option except the reflog and configuration is copied instead of being moved. This is useful for e.g. copying a topic branch to a new version, e.g. work to work-2 after submitting the work topic to the list, while preserving all the tracking info and other configuration that goes with the branch, and unlike --move keeping the other already-submitted branch around for reference. Like --move, when the source branch is the currently checked out branch the HEAD is moved to the destination branch. In the case of --move we don't really have a choice (other than remaining on a detached HEAD) and in order to keep the functionality consistent, we are doing it in similar way for --copy too. The most common usage of this feature is expected to be moving to a new topic branch which is a copy of the current one, in that case moving to the target branch is what the user wants, and doesn't unexpectedly behave differently than --move would. One outstanding caveat of this implementation is that: git checkout maint && git checkout master && git branch -c topic && git checkout - Will check out 'maint' instead of 'master'. This is because the @{-N} feature (or its -1 shorthand "-") relies on HEAD reflogs created by the checkout command, so in this case we'll checkout maint instead of master, as the user might expect. What to do about that is left to a future change. Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Sahil Dua <sahildua2305@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23ref_update_reject_duplicates(): expose function to whole refs moduleLibravatar Michael Haggerty1-0/+8
It will soon have some other users. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23ref_transaction_prepare(): new optional step for reference updatesLibravatar Michael Haggerty1-10/+35
In the future, compound reference stores will sometimes need to modify references in two different reference stores at the same time, meaning that a single logical reference transaction might have to be implemented as two internal sub-transactions. They won't want to call `ref_transaction_commit()` for the two sub-transactions one after the other, because that wouldn't be atomic (the first commit could succeed and the second one fail). Instead, they will want to prepare both sub-transactions (i.e., obtain any necessary locks and do any pre-checks), and only if both prepare steps succeed, then commit both sub-transactions. Start preparing for that day by adding a new, optional `ref_transaction_prepare()` step to the reference transaction sequence, which obtains the locks and does any prechecks, reporting any errors that occur. Also add a `ref_transaction_abort()` function that can be used to abort a sub-transaction even if it has already been prepared. That is on the side of the public-facing API. On the side of the `ref_store` VTABLE, get rid of `transaction_commit` and instead add methods `transaction_prepare`, `transaction_finish`, and `transaction_abort`. A `ref_transaction_commit()` now basically calls methods `transaction_prepare` then `transaction_finish`. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23ref_store: take a `msg` parameter when deleting referencesLibravatar Michael Haggerty1-1/+1
Just because the files backend can't retain reflogs for deleted references is no reason that they shouldn't be supported by the virtual method interface. Also, `delete_ref()` and `refs_delete_ref()` have already gained `msg` parameters. Now let's add them to `delete_refs()` and `refs_delete_refs()`. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23ref_iterator_begin_fn(): fix docstringLibravatar Michael Haggerty1-3/+4
The iterator returned by this function only includes references whose names start with the whole prefix, not all of those in `find_containing_dir(prefix)` as the old docstring claimed. This docstring was probably copy-pasted from old ref-cache code, which had the old specification. But now, `cache_ref_iterator_begin()` (from which the files reference iterator gets its values) automatically wraps its output using `prefix_ref_iterator_begin()` when necessary, so it has the stricter behavior. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>