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2022-01-03Merge branch 'ns/tmp-objdir'Libravatar Junio C Hamano1-1/+1
New interface into the tmp-objdir API to help in-core use of the quarantine feature. * ns/tmp-objdir: tmp-objdir: disable ref updates when replacing the primary odb tmp-objdir: new API for creating temporary writable databases
2021-12-15Merge branch 'hn/allow-bogus-oid-in-ref-tests'Libravatar Junio C Hamano1-3/+4
The test helper for refs subsystem learned to write bogus and/or nonexistent object name to refs to simulate error situations we want to test Git in. * hn/allow-bogus-oid-in-ref-tests: t1430: create valid symrefs using test-helper t1430: remove refs using test-tool refs: introduce REF_SKIP_REFNAME_VERIFICATION flag refs: introduce REF_SKIP_OID_VERIFICATION flag refs: update comment. test-ref-store: plug memory leak in cmd_delete_refs test-ref-store: parse symbolic flag constants test-ref-store: remove force-create argument for create-reflog
2021-12-10Merge branch 'hn/create-reflog-simplify'Libravatar Junio C Hamano1-5/+4
A small simplification of API. * hn/create-reflog-simplify: refs: drop force_create argument of create_reflog API
2021-12-10Merge branch 'jk/refs-g11-workaround'Libravatar Junio C Hamano1-0/+7
Workaround for a false-alarm by gcc-11 * jk/refs-g11-workaround: refs: work around gcc-11 warning with REF_HAVE_NEW
2021-12-08tmp-objdir: disable ref updates when replacing the primary odbLibravatar Neeraj Singh1-1/+1
When creating a subprocess with a temporary ODB, we set the GIT_QUARANTINE_ENVIRONMENT env var to tell child Git processes not to update refs, since the tmp-objdir may go away. Introduce a similar mechanism for in-process temporary ODBs when we call tmp_objdir_replace_primary_odb. Now both mechanisms set the disable_ref_updates flag on the odb, which is queried by the ref_transaction_prepare function. Peff's test case [1] was invoking ref updates via the cachetextconv setting. That particular code silently does nothing when a ref update is forbidden. See the call to notes_cache_put in fill_textconv where errors are ignored. [1] https://lore.kernel.org/git/YVOn3hDsb5pnxR53@coredump.intra.peff.net/ Reported-by: Jeff King <peff@peff.net> Signed-off-by: Neeraj Singh <neerajsi@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-07refs: introduce REF_SKIP_REFNAME_VERIFICATION flagLibravatar Han-Wen Nienhuys1-3/+4
Use this flag with the test-helper in t1430, to avoid direct writes to the ref database. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-29Merge branch 'ab/refs-errno-cleanup'Libravatar Junio C Hamano1-58/+66
The "remainder" of hn/refs-errno-cleanup topic. * ab/refs-errno-cleanup: (21 commits) refs API: post-migration API renaming [2/2] refs API: post-migration API renaming [1/2] refs API: don't expose "errno" in run_transaction_hook() refs API: make expand_ref() & repo_dwim_log() not set errno refs API: make resolve_ref_unsafe() not set errno refs API: make refs_ref_exists() not set errno refs API: make refs_resolve_refdup() not set errno refs tests: ignore ignore errno in test-ref-store helper refs API: ignore errno in worktree.c's find_shared_symref() refs API: ignore errno in worktree.c's add_head_info() refs API: make files_copy_or_rename_ref() et al not set errno refs API: make loose_fill_ref_dir() not set errno refs API: make resolve_gitlink_ref() not set errno refs API: remove refs_read_ref_full() wrapper refs/files: remove "name exist?" check in lock_ref_oid_basic() reflog tests: add --updateref tests refs API: make refs_rename_ref_available() static refs API: make parse_loose_ref_contents() not set errno refs API: make refs_read_raw_ref() not set errno refs API: add a version of refs_resolve_ref_unsafe() with "errno" ...
2021-11-22refs: drop force_create argument of create_reflog APILibravatar Han-Wen Nienhuys1-5/+4
There is only one caller, builtin/checkout.c, and it hardcodes force_create=1. This argument was introduced in abd0cd3a301 (refs: new public ref function: safe_create_reflog, 2015-07-21), which promised to immediately use it in a follow-on commit, but that never happened. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-19refs: work around gcc-11 warning with REF_HAVE_NEWLibravatar Jeff King1-0/+7
Using gcc-11 (or 12) to compile refs.o with -O3 results in: In file included from hashmap.h:4, from cache.h:6, from refs.c:5: In function ‘oidcpy’, inlined from ‘ref_transaction_add_update’ at refs.c:1065:3, inlined from ‘ref_transaction_update’ at refs.c:1094:2, inlined from ‘ref_transaction_verify’ at refs.c:1132:9: hash.h:262:9: warning: argument 2 null where non-null expected [-Wnonnull] 262 | memcpy(dst->hash, src->hash, GIT_MAX_RAWSZ); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from git-compat-util.h:177, from cache.h:4, from refs.c:5: refs.c: In function ‘ref_transaction_verify’: /usr/include/string.h:43:14: note: in a call to function ‘memcpy’ declared ‘nonnull’ 43 | extern void *memcpy (void *__restrict __dest, const void *__restrict __src, | ^~~~~~ That call to memcpy() is in a conditional block that requires REF_HAVE_NEW to be set. But in ref_transaction_update(), we make sure it isn't set coming in: if (flags & ~REF_TRANSACTION_UPDATE_ALLOWED_FLAGS) BUG("illegal flags 0x%x passed to ref_transaction_update()", flags); and then only set it if the variable isn't NULL: flags |= (new_oid ? REF_HAVE_NEW : 0) | (old_oid ? REF_HAVE_OLD : 0); So it should be impossible to reach that memcpy() with a NULL oid. But for whatever reason, gcc doesn't accept that hitting the BUG() means we won't go any further, even though it's marked with the noreturn attribute. And the conditional is correct; ALLOWED_FLAGS doesn't contain HAVE_NEW or HAVE_OLD, and you can even simplify it to check for those flags explicitly and the compiler still complains. We can work around this by just clearing the disallowed flags explicitly. This should be a noop because of the BUG() check, but it makes the compiler happy. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-25Merge branch 'jt/no-abuse-alternate-odb-for-submodules'Libravatar Junio C Hamano1-8/+24
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
2021-10-16refs API: post-migration API renaming [2/2]Libravatar Ævar Arnfjörð Bjarmason1-8/+8
Rename the transitory refs_werrres_ref_unsafe() function to refs_resolve_ref_unsafe(), now that all callers of the old function have learned to pass in a "failure_errno" parameter. The coccinelle semantic patch added in the preceding commit works, but I couldn't figure out how to get spatch(1) to re-flow these argument lists (and sometimes make lines way too long), so this rename was done with: perl -pi -e 's/refs_werrres_ref_unsafe/refs_resolve_ref_unsafe/g' \ $(git grep -l refs_werrres_ref_unsafe -- '*.c') But after that "make contrib/coccinelle/refs.cocci.patch" comes up empty, so the result would have been the same. Let's remove that transitory semantic patch file, we won't need to retain it for any other in-flight changes, refs_werrres_ref_unsafe() only existed within this patch series. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: post-migration API renaming [1/2]Libravatar Ævar Arnfjörð Bjarmason1-14/+1
In preceding commits all callers of refs_resolve_ref_unsafe() were migrated to the transitory refs_werrres_ref_unsafe() function. As a first step in getting rid of it let's remove the old function from the public API (it went unused in a preceding commit). We then provide both a coccinelle rule to do the rename, and a macro to avoid breaking the existing callers. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: don't expose "errno" in run_transaction_hook()Libravatar Ævar Arnfjörð Bjarmason1-1/+4
In run_transaction_hook() we've checked errno since 67541597670 (refs: implement reference transaction hook, 2020-06-19), let's reset errno afterwards to make sure nobody using refs.c directly or indirectly relies on it. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: make expand_ref() & repo_dwim_log() not set errnoLibravatar Ævar Arnfjörð Bjarmason1-5/+10
The use of these two is rather trivial, and it's easy to see none of their callers care about errno. So let's move them from refs_resolve_ref_unsafe() to refs_resolve_ref_unsafe_with_errno(), these were the last two callers, so we can get rid of that wrapper function. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: make resolve_ref_unsafe() not set errnoLibravatar Ævar Arnfjörð Bjarmason1-2/+4
Change the resolve_ref_unsafe() wrapper function to use the underlying refs_werrres_ref_unsafe() directly. From a reading of the callers I determined that the only one who cared about errno was a sequencer.c caller added in e47c6cafcb5 (commit: move print_commit_summary() to libgit, 2017-11-24), I'm migrating it to using refs_werrres_ref_unsafe() directly. This adds another "set errno" instance, but in this case it's OK and idiomatic. We are setting it just before calling die_errno(). We could have some hypothetical die_errno_var(&saved_errno, ...) here, but I don't think it's worth it. The problem with errno is subtle action at distance, not this sort of thing. We already use this pattern in a couple of places in wrapper.c Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: make refs_ref_exists() not set errnoLibravatar Ævar Arnfjörð Bjarmason1-1/+3
Move refs_ref_exists from the legacy refs_resolve_ref_unsafe() to the new refs_werrres_ref_unsafe(). I have read its callers and determined that they don't care about errno being set, in particular: git grep -W -w -e refs_ref_exists -e ref_exists Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: make refs_resolve_refdup() not set errnoLibravatar Ævar Arnfjörð Bjarmason1-2/+3
Move refs_resolve_refdup() from the legacy refs_resolve_ref_unsafe() to the new refs_werrres_ref_unsafe(). I have read its callers and determined that they don't care about errno being set. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: make resolve_gitlink_ref() not set errnoLibravatar Ævar Arnfjörð Bjarmason1-2/+3
I have carefully read the upstream callers of resolve_gitlink_ref() and determined that they don't care about errno. So let's move away from the errno-setting refs_resolve_ref_unsafe() wrapper to refs_werrres_ref_unsafe(), and explicitly ignore the errno it sets for us. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: remove refs_read_ref_full() wrapperLibravatar Ævar Arnfjörð Bjarmason1-11/+9
Remove the refs_read_ref_full() wrapper in favor of migrating various refs.c API users to the underlying refs_werrres_ref_unsafe() function. A careful reading of these callers shows that the callers of this function did not care about "errno", by moving away from the refs_resolve_ref_unsafe() wrapper we can be sure that nothing relies on it anymore. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: make refs_rename_ref_available() staticLibravatar Ævar Arnfjörð Bjarmason1-19/+0
Move the refs_rename_ref_available() function into "refs/files-backend.c". It is file-backend specific. This function was added in 5fe7d825da8 (refs.c: pass a list of names to skip to is_refname_available, 2014-05-01) as rename_ref_available() and was only ever used in this one file-backend specific codepath. So let's move it there. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-16refs API: make parse_loose_ref_contents() not set errnoLibravatar Han-Wen Nienhuys1-3/+5
Change the parse_loose_ref_contents() function to stop setting "errno" and failure, and to instead pass up a "failure_errno" via a parameter. This requires changing its callers to do the same. The EINVAL error from parse_loose_ref_contents is used in files-backend to create a custom error message. In untangling this we discovered a tricky edge case. The refs_read_special_head() function was relying on parse_loose_ref_contents() setting EINVAL. By converting it to use "saved_errno" we can migrate away from "errno" in this part of the code entirely, and do away with an existing "save_errno" pattern, its only purpose was to not clobber the "errno" we previously needed at the end of files_read_raw_ref(). Let's assert that we can do that by not having files_read_raw_ref() itself operate on *failure_errno in addition to passing it on. Instead we'll assert that if we return non-zero we actually do set errno, thus assuring ourselves and callers that they can trust the resulting "failure_errno". 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>
2021-10-16refs API: make refs_read_raw_ref() not set errnoLibravatar Han-Wen Nienhuys1-8/+16
Add a "failure_errno" to refs_read_raw_ref(), his allows refs_werrres_ref_unsafe() to pass along its "failure_errno", as a first step before its own callers are migrated to pass it further up the chain. We are leaving out out the refs_read_special_head() in refs_read_raw_ref() for now, as noted in a subsequent commit moving it to "failure_errno" will require some special consideration. 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>
2021-10-16refs API: add a version of refs_resolve_ref_unsafe() with "errno"Libravatar Ævar Arnfjörð Bjarmason1-9/+27
Add a new refs_werrres_ref_unsafe() function, which is like refs_resolve_ref_unsafe() except that it explicitly saves away the "errno" to a passed-in parameter, the refs_resolve_ref_unsafe() then becomes a wrapper for it. In subsequent commits we'll migrate code over to it, before finally making "refs_resolve_ref_unsafe()" with an "errno" parameter the canonical version, so this this function exists only so that we can incrementally migrate callers, it will be going away in a subsequent commit. As the added comment notes has a rather tortured name to be the same length as "refs_resolve_ref_unsafe", to avoid churn as we won't need to re-indent the argument lists, similarly the documentation and structure of it in refs.h is designed to minimize a diff in a subsequent commit, where that documentation will be added to the new refs_resolve_ref_unsafe(). At the end of this migration the "meaningful errno" TODO item left in 76d70dc0c63 (refs.c: make resolve_ref_unsafe set errno to something meaningful on error, 2014-06-20) will be resolved. As can be seen from the use of refs_read_raw_ref() we'll also need to convert some functions that the new refs_werrres_ref_unsafe() itself calls to take this "failure_errno". That will be done in subsequent commits. 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>
2021-10-13Merge branch 'ab/config-based-hooks-1'Libravatar Junio C Hamano1-0/+1
Mostly preliminary clean-up in the hook API. * ab/config-based-hooks-1: hook-list.h: add a generated list of hooks, like config-list.h hook.c users: use "hook_exists()" instead of "find_hook()" hook.c: add a hook_exists() wrapper and use it in bugreport.c hook.[ch]: move find_hook() from run-command.c to hook.c Makefile: remove an out-of-date comment Makefile: don't perform "mv $@+ $@" dance for $(GENERATED_H) Makefile: stop hardcoding {command,config}-list.h Makefile: mark "check" target as .PHONY
2021-10-11Merge branch 'jk/ref-paranoia'Libravatar Junio C Hamano1-22/+20
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 Tan1-1/+2
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 Tan1-7/+22
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>
2021-10-06Merge branch 'ab/retire-refs-unused-funcs'Libravatar Junio C Hamano1-5/+0
Code cleanup. * ab/retire-refs-unused-funcs: refs/ref-cache.[ch]: remove "incomplete" from create_dir_entry() refs/ref-cache.c: remove "mkdir" parameter from find_containing_dir() refs/ref-cache.[ch]: remove unused add_ref_entry() refs/ref-cache.[ch]: remove unused remove_entry_from_dir() refs.[ch]: remove unused ref_storage_backend_exists()
2021-09-28refs.[ch]: remove unused ref_storage_backend_exists()Libravatar Ævar Arnfjörð Bjarmason1-5/+0
This function was added in 3dce444f178 (refs: add a backend method structure, 2016-09-04), but has never been used by anything. The only caller that might care uses find_ref_storage_backend() directly. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27refs: drop "broken" flag from for_each_fullref_in()Libravatar Jeff King1-16/+6
No callers pass in anything but "0" here. Likewise to our sibling functions. Note that some of them ferry along the flag, but none of their callers pass anything but "0" either. Nor is anybody likely to change that. Callers which really want to see all of the raw refs use for_each_rawref(). And anybody interested in iterating a subset of the refs will likely be happy to use the now-default behavior of showing broken refs, but omitting dangling symlinks. So we can get rid of this whole feature. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27repack, prune: drop GIT_REF_PARANOIA settingsLibravatar Jeff King1-0/+2
Now that GIT_REF_PARANOIA is the default, we don't need to selectively enable it for destructive operations. In fact, it's harmful to do so, because it overrides any GIT_REF_PARANOIA=0 setting that the user may have provided (because they're trying to work around some corruption). With these uses gone, we can further clean up the ref_paranoia global, and make it a static variable inside the refs code. 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: turn on GIT_REF_PARANOIA by defaultLibravatar Jeff King1-1/+1
The original point of the GIT_REF_PARANOIA flag was to include broken refs in iterations, so that possibly-destructive operations would not silently ignore them (and would generally instead try to operate on the oids and fail when the objects could not be accessed). We already turned this on by default for some dangerous operations, like "repack -ad" (where missing a reachability tip would mean dropping the associated history). But it was not on for general use, even though it could easily result in the spreading of corruption (e.g., imagine cloning a repository which simply omits some of its refs because their objects are missing; the result quietly succeeds even though you did not clone everything!). This patch turns on GIT_REF_PARANOIA by default. So a clone as mentioned above would actually fail (upload-pack tells us about the broken ref, and when we ask for the objects, pack-objects fails to deliver them). This may be inconvenient when working with a corrupted repository, but: - we are better off to err on the side of complaining about corruption, and then provide mechanisms for explicitly loosening safety. - this is only one type of corruption anyway. If we are missing any other objects in the history that _aren't_ ref tips, then we'd behave similarly (happily show the ref, but then barf when we started traversing). We retain the GIT_REF_PARANOIA variable, but simply default it to "1" instead of "0". That gives the user an escape hatch for loosening this when working with a corrupt repository. It won't work across a remote connection to upload-pack (because we can't necessarily set environment variables on the remote), but there the client has other options (e.g., choosing which refs to fetch). As a bonus, this also makes ref iteration faster in general (because we don't have to call has_object_file() for each ref), though probably not noticeably so in the general case. In a repo with a million refs, it shaved a few hundred milliseconds off of upload-pack's advertisement; that's noticeable, but most repos are not nearly that large. The possible downside here is that any operation which iterates refs but doesn't ever open their objects may now quietly claim to have X when the object is corrupted (e.g., "git rev-list new-branch --not --all" will treat a broken ref as uninteresting). But again, that's not really any different than corruption below the ref level. We might have refs/heads/old-branch as non-corrupt, but we are not actively checking that we have the entire reachable history. Or the pointed-to object could even be corrupted on-disk (but our "do we have it" check would still succeed). In that sense, this is merely bringing ref-corruption in line with general object corruption. One alternative implementation would be to actually check for broken refs, and then _immediately die_ if we see any. That would cause the "rev-list --not --all" case above to abort immediately. But in many ways that's the worst of all worlds: - it still spends time looking up the objects an extra time - it still doesn't catch corruption below the ref level - it's even more inconvenient; with the current implementation of GIT_REF_PARANOIA for something like upload-pack, we can make the advertisement and let the client choose a non-broken piece of history. If we bail as soon as we see a broken ref, they cannot even see the advertisement. The test changes here show some of the fallout. A non-destructive "git repack -adk" now fails by default (but we can override it). Deleting a broken ref now actually tells the hooks the correct "before" state, rather than a confusing null oid. 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: omit dangling symrefs when using GIT_REF_PARANOIALibravatar Jeff King1-4/+8
Dangling symrefs aren't actually a corruption problem. It's perfectly fine for refs/remotes/origin/HEAD to point to an unborn branch. And in particular, if you are trying to establish reachability, a symref that points nowhere doesn't matter either way. Any ref it could point to will be examined during the rest of the traversal. It's possible that a symref pointing nowhere _could_ be a sign that the ref it was meant to point to was deleted accidentally (e.g., via corruption). But there is no particular reason to think that is true for any given case, and in the meantime, GIT_REF_PARANOIA kicking in automatically for some operations means they'll fail unnecessarily. So let's loosen it just a bit. The new test in t5312 shows off an example that is safe, but currently fails (and no longer does after this patch). Note that we don't do anything if the caller explicitly asked for DO_FOR_EACH_INCLUDE_BROKEN. In that case they may be looking for dangling symrefs themselves, and setting GIT_REF_PARANOIA should not _loosen_ things from what the caller asked for. 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 King1-4/+6
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>
2021-09-27hook.[ch]: move find_hook() from run-command.c to hook.cLibravatar Ævar Arnfjörð Bjarmason1-0/+1
Move the find_hook() function from run-command.c to a new hook.c library. This change establishes a stub library that's pretty pointless right now, but will see much wider use with Emily Shaffer's upcoming "configuration-based hooks" series. Eventually all the hook related code will live in hook.[ch]. Let's start that process by moving the simple find_hook() function over as-is. Signed-off-by: Emily Shaffer <emilyshaffer@google.com> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-25refs: make errno output explicit for read_raw_ref_fnLibravatar Han-Wen Nienhuys1-1/+1
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 API: remove OID argument to reflog_expire()Libravatar Ævar Arnfjörð Bjarmason1-4/+4
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>
2021-08-25refs: make repo_dwim_log() accept a NULL oidLibravatar Ævar Arnfjörð Bjarmason1-2/+3
Change the repo_dwim_log() function initially added as dwim_log() in eb3a48221fd (log --reflog: use dwim_log, 2007-02-09) to accept a NULL oid parameter. The refs_resolve_ref_unsafe() function it invokes already deals with it, but it didn't. This allows for a bit more clarity in a reflog-walk.c codepath added in f2eba66d4d1 (Enable HEAD@{...} and make it independent from the current branch, 2007-02-03). We'll shortly use this in builtin/reflog.c as well. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-16Merge branch 'hn/refs-iterator-peel-returns-boolean'Libravatar Junio C Hamano1-1/+1
Tiny API tweak. * hn/refs-iterator-peel-returns-boolean: refs: make explicit that ref_iterator_peel returns boolean
2021-05-20refs: make explicit that ref_iterator_peel returns booleanLibravatar Han-Wen Nienhuys1-1/+1
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>
2021-05-10Merge branch 'bc/hash-transition-interop-part-1'Libravatar Junio C Hamano1-2/+2
SHA-256 transition. * bc/hash-transition-interop-part-1: hex: print objects using the hash algorithm member hex: default to the_hash_algo on zero algorithm value builtin/pack-objects: avoid using struct object_id for pack hash commit-graph: don't store file hashes as struct object_id builtin/show-index: set the algorithm for object IDs hash: provide per-algorithm null OIDs hash: set, copy, and use algo field in struct object_id builtin/pack-redundant: avoid casting buffers to struct object_id Use the final_oid_fn to finalize hashing of object IDs hash: add a function to finalize object IDs http-push: set algorithm when reading object ID Always use oidread to read into struct object_id hash: add an algo member to struct object_id
2021-04-27hash: provide per-algorithm null OIDsLibravatar brian m. carlson1-2/+2
Up until recently, object IDs did not have an algorithm member, only a hash. Consequently, it was possible to share one null (all-zeros) object ID among all hash algorithms. Now that we're going to be handling objects from multiple hash algorithms, it's important to make sure that all object IDs have a correct algorithm field. Introduce a per-algorithm null OID, and add it to struct hash_algo. Introduce a wrapper function as well, and use it everywhere we used to use the null_oid constant. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-13lookup_unknown_object(): take a repository argumentLibravatar Jeff King1-1/+1
All of the other lookup_foo() functions take a repository argument, but lookup_unknown_object() was never converted, and it uses the_repository internally. Let's fix that. We could leave a wrapper that uses the_repository, but there aren't that many calls, so we'll just convert them all. I looked briefly at each site to see if we had a repository struct (besides the_repository) we could pass, but none of them do (so this conversion to pass the_repository is a pure noop in each case, though it does take us one step closer to eventually getting rid of the_repository). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-13use CALLOC_ARRAYLibravatar René Scharfe1-2/+2
Add and apply a semantic patch for converting code that open-codes CALLOC_ARRAY to use it instead. It shortens the code and infers the element size automatically. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05Merge branch 'tb/ls-refs-optim'Libravatar Junio C Hamano1-0/+87
The ls-refs protocol operation has been optimized to narrow the sub-hierarchy of refs/ it walks to produce response. * tb/ls-refs-optim: ls-refs.c: traverse prefixes of disjoint "ref-prefix" sets ls-refs.c: initialize 'prefixes' before using it refs: expose 'for_each_fullref_in_prefixes'
2021-02-03Merge branch 'jk/peel-iterated-oid'Libravatar Junio C Hamano1-23/+6
The peel_ref() API has been replaced with peel_iterated_oid(). * jk/peel-iterated-oid: refs: switch peel_ref() to peel_iterated_oid()
2021-01-22refs: expose 'for_each_fullref_in_prefixes'Libravatar Taylor Blau1-0/+87
This function was used in the ref-filter.c code to find the longest common prefix of among a set of refspecs, and then to iterate all of the references that descend from that prefix. A future patch will want to use that same code from ls-refs.c, so prepare by exposing and moving it to refs.c. Since there is nothing specific to the ref-filter code here (other than that it was previously the only caller of this function), this really belongs in the more generic refs.h header. The code moved in this patch is identical before and after, with the one exception of renaming some arguments to be consistent with other functions exposed in refs.h. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-21refs: switch peel_ref() to peel_iterated_oid()Libravatar Jeff King1-23/+6
The peel_ref() interface is confusing and error-prone: - it's typically used by ref iteration callbacks that have both a refname and oid. But since they pass only the refname, we may load the ref value from the filesystem again. This is inefficient, but also means we are open to a race if somebody simultaneously updates the ref. E.g., this: int some_ref_cb(const char *refname, const struct object_id *oid, ...) { if (!peel_ref(refname, &peeled)) printf("%s peels to %s", oid_to_hex(oid), oid_to_hex(&peeled); } could print nonsense. It is correct to say "refname peels to..." (you may see the "before" value or the "after" value, either of which is consistent), but mentioning both oids may be mixing before/after values. Worse, whether this is possible depends on whether the optimization to read from the current iterator value kicks in. So it is actually not possible with: for_each_ref(some_ref_cb); but it _is_ possible with: head_ref(some_ref_cb); which does not use the iterator mechanism (though in practice, HEAD should never peel to anything, so this may not be triggerable). - it must take a fully-qualified refname for the read_ref_full() code path to work. Yet we routinely pass it partial refnames from callbacks to for_each_tag_ref(), etc. This happens to work when iterating because there we do not call read_ref_full() at all, and only use the passed refname to check if it is the same as the iterator. But the requirements for the function parameters are quite unclear. Instead of taking a refname, let's instead take an oid. That fixes both problems. It's a little funny for a "ref" function not to involve refs at all. The key thing is that it's optimizing under the hood based on having access to the ref iterator. So let's change the name to make it clear why you'd want this function versus just peel_object(). There are two other directions I considered but rejected: - we could pass the peel information into the each_ref_fn callback. However, we don't know if the caller actually wants it or not. For packed-refs, providing it is essentially free. But for loose refs, we actually have to peel the object, which would be wasteful in most cases. We could likewise pass in a flag to the callback indicating whether the peeled information is known, but that complicates those callbacks, as they then have to decide whether to manually peel themselves. Plus it requires changing the interface of every callback, whether they care about peeling or not, and there are many of them. - we could make a function to return the peeled value of the current iterated ref (computing it if necessary), and BUG() otherwise. I.e.: int peel_current_iterated_ref(struct object_id *out); Each of the current callers is an each_ref_fn callback, so they'd mostly be happy. But: - we use those callbacks with functions like head_ref(), which do not use the iteration code. So we'd need to handle the fallback case there, anyway. - it's possible that a caller would want to call into generic code that sometimes is used during iteration and sometimes not. This encapsulates the logic to do the fast thing when possible, and fallback when necessary. The implementation is mostly obvious, but I want to call out a few things in the patch: - the test-tool coverage for peel_ref() is now meaningless, as it all collapses to a single peel_object() call (arguably they were pretty uninteresting before; the tricky part of that function is the fast-path we see during iteration, but these calls didn't trigger that). I've just dropped it entirely, though note that some other tests relied on the tags we created; I've moved that creation to the tests where it matters. - we no longer need to take a ref_store parameter, since we'd never look up a ref now. We do still rely on a global "current iterator" variable which _could_ be kept per-ref-store. But in practice this is only useful if there are multiple recursive iterations, at which point the more appropriate solution is probably a stack of iterators. No caller used the actual ref-store parameter anyway (they all call the wrapper that passes the_repository). - the original only kicked in the optimization when the "refname" pointer matched (i.e., not string comparison). We do likewise with the "oid" parameter here, but fall back to doing an actual oideq() call. This in theory lets us kick in the optimization more often, though in practice no current caller cares. It should never be wrong, though (peeling is a property of an object, so two refs pointing to the same object would peel identically). - the original took care not to touch the peeled out-parameter unless we found something to put in it. But no caller cares about this, and anyway, it is enforced by peel_object() itself (and even in the optimized iterator case, that's where we eventually end up). We can shorten the code and avoid an extra copy by just passing the out-parameter through the stack. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-11refs: allow @{n} to work with n-sized reflogLibravatar Denton Liu1-14/+32
This sequence works $ git checkout -b newbranch $ git commit --allow-empty -m one $ git show -s newbranch@{1} and shows the state that was immediately after the newbranch was created. But then if you do $ git reflog expire --expire=now refs/heads/newbranch $ git commit --allow=empty -m two $ git show -s newbranch@{1} you'd be scolded with fatal: log for 'newbranch' only has 1 entries While it is true that it has only 1 entry, we have enough information in that single entry that records the transition between the state in which the tip of the branch was pointing at commit 'one' to the new commit 'two' built on it, so we should be able to answer "what object newbranch was pointing at?". But we refuse to do so. Make @{0} the special case where we use the new side to look up that entry. Otherwise, look up @{n} using the old side of the (n-1)th entry of the reflog. Suggested-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-10refs: factor out set_read_ref_cutoffs()Libravatar Denton Liu1-17/+17
This block of code is duplicated twice. In a future commit, it will be duplicated for a third time. Factor out the common functionality into set_read_ref_cutoffs(). In the case of read_ref_at_ent(), we are incrementing `cb->reccnt` at the beginning of the function. Move these to right before the return so that the `cb->reccnt - 1` is changed to `cb->reccnt` and it can be cleanly factored out into set_read_ref_cutoffs(). The duplication of the increment statements will be removed in a future patch. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>