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2022-04-13Revert "Merge branch 'ps/avoid-unnecessary-hook-invocation-with-packed-refs'"Libravatar Junio C Hamano1-8/+3
This reverts commit 991b4d47f0accd3955d05927d5ce434e03ffbdb6, reversing changes made to bcd020f88e1e22f38422ac3f73ab06b34ec4bef1.
2022-03-17refs debug: add a wrapper for "read_symbolic_ref"Libravatar Ævar Arnfjörð Bjarmason1-12/+1
In cd475b3b038 (refs: add ability for backends to special-case reading of symbolic refs, 2022-03-01) when the "read_symbolic_ref" callback was added we'd fall back on "refs_read_raw_ref" if there wasn't any backend implementation of "read_symbolic_ref". As discussed in the preceding commit this would only happen if we were running the "debug" backend, e.g. in the "setup for ref completion" test in t9902-completion.sh with: GIT_TRACE_REFS=1 git fetch --no-tags other Let's improve the trace output, but and also eliminate the now-redundant refs_read_raw_ref() fallback case. As noted in the preceding commit the "packed" backend will never call refs_read_symbolic_ref() (nor is it ever going to). For any future backend such as reftable it's OK to ask that they either implement this (or a wrapper) themselves. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-16Merge branch 'ps/fetch-mirror-optim'Libravatar Junio C Hamano1-0/+17
Various optimization for "git fetch". * ps/fetch-mirror-optim: refs/files-backend: optimize reading of symbolic refs remote: read symbolic refs via `refs_read_symbolic_ref()` refs: add ability for backends to special-case reading of symbolic refs fetch: avoid lookup of commits when not appending to FETCH_HEAD upload-pack: look up "want" lines via commit-graph
2022-03-13Merge branch 'ps/fetch-atomic'Libravatar Junio C Hamano1-0/+16
"git fetch" can make two separate fetches, but ref updates coming from them were in two separate ref transactions under "--atomic", which has been corrected. * ps/fetch-atomic: fetch: make `--atomic` flag cover pruning of refs fetch: make `--atomic` flag cover backfilling of tags refs: add interface to iterate over queued transactional updates fetch: report errors when backfilling tags fails fetch: control lifecycle of FETCH_HEAD in a single place fetch: backfill tags before setting upstream fetch: increase test coverage of fetches
2022-03-01refs: add ability for backends to special-case reading of symbolic refsLibravatar Patrick Steinhardt1-0/+17
Reading of symbolic and non-symbolic references is currently treated the same in reference backends: we always call `refs_read_raw_ref()` and then decide based on the returned flags what type it is. This has one downside though: symbolic references may be treated different from normal references in a backend from normal references. The packed-refs backend for example doesn't even know about symbolic references, and as a result it is pointless to even ask it for one. There are cases where we really only care about whether a reference is symbolic or not, but don't care about whether it exists at all or may be a non-symbolic reference. But it is not possible to optimize for this case right now, and as a consequence we will always first check for a loose reference to exist, and if it doesn't, we'll query the packed-refs backend for a known-to-not-be-symbolic reference. This is inefficient and requires us to search all packed references even though we know to not care for the result at all. Introduce a new function `refs_read_symbolic_ref()` which allows us to fix this case. This function will only ever return symbolic references and can thus optimize for the scenario layed out above. By default, if the backend doesn't provide an implementation for it, we just use the old code path and fall back to `read_raw_ref()`. But in case the backend provides its own, more efficient implementation, we will use that one instead. Note that this function is explicitly designed to not distinguish between missing references and non-symbolic references. If it did, we'd be forced to always search the packed-refs backend to see whether the symbolic reference the user asked for really doesn't exist, or if it exists as a non-symbolic reference. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-01Merge branch 'ps/fetch-atomic' into ps/fetch-mirror-optimLibravatar Junio C Hamano1-0/+16
* ps/fetch-atomic: fetch: make `--atomic` flag cover pruning of refs fetch: make `--atomic` flag cover backfilling of tags refs: add interface to iterate over queued transactional updates fetch: report errors when backfilling tags fails fetch: control lifecycle of FETCH_HEAD in a single place fetch: backfill tags before setting upstream fetch: increase test coverage of fetches
2022-02-25Merge branch 'ab/date-mode-release'Libravatar Junio C Hamano1-0/+1
Plug (some) memory leaks around parse_date_format(). * ab/date-mode-release: date API: add and use a date_mode_release() date API: add basic API docs date API: provide and use a DATE_MODE_INIT date API: create a date.h, split from cache.h cache.h: remove always unused show_date_human() declaration
2022-02-18Merge branch 'ps/avoid-unnecessary-hook-invocation-with-packed-refs'Libravatar Junio C Hamano1-3/+8
Because a deletion of ref would need to remove it from both the loose ref store and the packed ref store, a delete-ref operation that logically removes one ref may end up invoking ref-transaction hook twice, which has been corrected. * ps/avoid-unnecessary-hook-invocation-with-packed-refs: refs: skip hooks when deleting uncovered packed refs refs: do not execute reference-transaction hook on packing refs refs: demonstrate excessive execution of the reference-transaction hook refs: allow skipping the reference-transaction hook refs: allow passing flags when beginning transactions refs: extract packed_refs_delete_refs() to allow control of transaction
2022-02-17refs: add interface to iterate over queued transactional updatesLibravatar Patrick Steinhardt1-0/+16
There is no way for a caller to see whether a reference update has already been queued up for a given reference transaction. There are multiple alternatives to provide this functionality: - We may add a function that simply tells us whether a specific reference has already been queued. If implemented naively then this would potentially be quadratic in runtime behaviour if this question is asked repeatedly because we have to iterate over all references every time. The alternative would be to add a hashmap of all queued reference updates to speed up the lookup, but this adds overhead to all callers. - We may add a flag to `ref_transaction_add_update()` that causes it to skip duplicates, but this has the same runtime concerns as the first alternative. - We may add an interface which lets callers collect all updates which have already been queued such that he can avoid re-adding them. This is the most flexible approach and puts the burden on the caller, but also allows us to not impact any of the existing callsites which don't need this information. This commit implements the last approach: it allows us to compute the map of already-queued updates once up front such that we can then skip all subsequent references which are already part of this map. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-16date API: create a date.h, split from cache.hLibravatar Ævar Arnfjörð Bjarmason1-0/+1
Move the declaration of the date.c functions from cache.h, and adjust the relevant users to include the new date.h header. The show_ident_date() function belonged in pretty.h (it's defined in pretty.c), its two users outside of pretty.c didn't strictly need to include pretty.h, as they get it indirectly, but let's add it to them anyway. Similarly, the change to "builtin/{fast-import,show-branch,tag}.c" isn't needed as far as the compiler is concerned, but since they all use the "DATE_MODE()" macro we now define in date.h, let's have them include it. We could simply include this new header in "cache.h", but as this change shows these functions weren't common enough to warrant including in it in the first place. By moving them out of cache.h changes to this API will no longer cause a (mostly) full re-build of the project when "make" is run. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-26refs API: remove "failure_errno" from refs_resolve_ref_unsafe()Libravatar Ævar Arnfjörð Bjarmason1-34/+17
Remove the now-unused "failure_errno" parameter from the refs_resolve_ref_unsafe() signature. In my recent 96f6623ada0 (Merge branch 'ab/refs-errno-cleanup', 2021-11-29) series we made all of its callers explicitly request the errno via an output parameter. As that series shows all but one caller ended up passing in a boilerplate "ignore_errno", since they only cared about whether the return value was NULL or not, i.e. if the ref could be resolved. There was one small issue with that series fixed with a follow-up in 31e39123695 (Merge branch 'ab/refs-errno-cleanup', 2022-01-14) a small bug in that series was fixed. After those two there was one caller left in sequencer.c that used the "failure_errno', but as of the preceding commit it uses a boilerplate "ignore_errno" instead. This leaves the public refs API without any use of "failure_errno" at all. We could still do with a bit of cleanup and generalization between refs.c and refs/files-backend.c before the "reftable" integration lands, but that's all internal to the reference code itself. So let's remove this output parameter. Not only isn't it used now, but it's unlikely that we'll want it again in the future. We'd like to slowly move the refs API to a more file-backend independent way of communicating error codes, having it use a "failure_errno" was only the first step in that direction. If this or any other function needs to communicate what specifically is wrong with the requested "refname" it'll be better to have the function set some output enum of well-defined error states than piggy-backend on "errno". Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-17refs: allow skipping the reference-transaction hookLibravatar Patrick Steinhardt1-0/+3
The reference-transaction hook is executing whenever we prepare, commit or abort a reference transaction. While this is mostly intentional, in case of the files backend we're leaking the implementation detail that the store is in fact a composite store with one loose and one packed backend to the caller. So while we want to execute the hook for all logical updates, executing it for such implementation details is unexpected. Prepare for a fix by adding a new flag which allows to skip execution of the hook. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-17refs: allow passing flags when beginning transactionsLibravatar Patrick Steinhardt1-3/+5
We do not currently have any flags when creating reference transactions, but we'll add one to disable execution of the reference transaction hook in some cases. Allow passing flags to `ref_store_transaction_begin()` to prepare for this change. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-14Merge branch 'ab/refs-errno-cleanup'Libravatar Junio C Hamano1-2/+0
A brown-paper-bag fix on top of a topic that was merged during this cycle. * ab/refs-errno-cleanup: refs API: use "failure_errno", not "errno"
2022-01-13refs API: use "failure_errno", not "errno"Libravatar Ævar Arnfjörð Bjarmason1-2/+0
Fix a logic error in refs_resolve_ref_unsafe() introduced in a recent series of mine to abstract the refs API away from errno. See 96f6623ada0 (Merge branch 'ab/refs-errno-cleanup', 2021-11-29)for that series. In that series introduction of "failure_errno" to refs_resolve_ref_unsafe came in ef18119dec8 (refs API: add a version of refs_resolve_ref_unsafe() with "errno", 2021-10-16). There we'd set "errno = 0" immediately before refs_read_raw_ref(), and then set "failure_errno" to "errno" if errno was non-zero afterwards. Then in the next commit 8b72fea7e91 (refs API: make refs_read_raw_ref() not set errno, 2021-10-16) we started expecting "refs_read_raw_ref()" to set "failure_errno". It would do that if refs_read_raw_ref() failed, but it wouldn't be the same errno. So we might set the "errno" here to any arbitrary bad value, and end up e.g. returning NULL when we meant to return the refname from refs_resolve_ref_unsafe(), or the other way around. Instrumenting this code will reveal cases where refs_read_raw_ref() will fail, and "errno" and "failure_errno" will be set to different values. In practice I haven't found a case where this scary bug changed anything in practice. The reason for that is that we'll not care about the actual value of "errno" here per-se, but only whether: 1. We have an errno 2. If it's one of ENOENT, EISDIR or ENOTDIR. See the adjacent code added in a1c1d8170db (refs_resolve_ref_unsafe: handle d/f conflicts for writes, 2017-10-06) I.e. if we clobber "failure_errno" with "errno", but it happened to be one of those three, and we'll clobber it with another one of the three we were OK. Perhaps there are cases where the difference ended up mattering, but I haven't found them. Instrumenting the test suite to fail if "errno" and "failure_errno" are different shows a lot of failures, checking if they're different *and* one is but not the other is outside that list of three "errno" values yields no failures. But let's fix the obvious bug. We should just stop paying attention to "errno" in refs_resolve_ref_unsafe(). In addition let's change the partial resetting of "errno" in files_read_raw_ref() to happen just before the "return", to ensure that any such bug will be more easily spotted in the future. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-10Merge branch 'hn/refs-debug-update'Libravatar Junio C Hamano1-2/+4
Debugging support for refs API. * hn/refs-debug-update: refs: centralize initialization of the base ref_store. refs: print error message in debug output refs: pass gitdir to packed_ref_store_create
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
2021-12-22refs: centralize initialization of the base ref_store.Libravatar Han-Wen Nienhuys1-2/+4
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>