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2024-07-02Merge branch 'ps/use-the-repository'Junio C Hamano1-3/+5
A CPP macro USE_THE_REPOSITORY_VARIABLE is introduced to help transition the codebase to rely less on the availability of the singleton the_repository instance. * ps/use-the-repository: hex: guard declarations with `USE_THE_REPOSITORY_VARIABLE` t/helper: remove dependency on `the_repository` in "proc-receive" t/helper: fix segfault in "oid-array" command without repository t/helper: use correct object hash in partial-clone helper compat/fsmonitor: fix socket path in networked SHA256 repos replace-object: use hash algorithm from passed-in repository protocol-caps: use hash algorithm from passed-in repository oidset: pass hash algorithm when parsing file http-fetch: don't crash when parsing packfile without a repo hash-ll: merge with "hash.h" refs: avoid include cycle with "repository.h" global: introduce `USE_THE_REPOSITORY_VARIABLE` macro hash: require hash algorithm in `empty_tree_oid_hex()` hash: require hash algorithm in `is_empty_{blob,tree}_oid()` hash: make `is_null_oid()` independent of `the_repository` hash: convert `oidcmp()` and `oideq()` to compare whole hash global: ensure that object IDs are always padded hash: require hash algorithm in `oidread()` and `oidclr()` hash: require hash algorithm in `hasheq()`, `hashcmp()` and `hashclr()` hash: drop (mostly) unused `is_empty_{blob,tree}_sha1()` functions
2024-06-20Merge branch 'kn/update-ref-symref'Junio C Hamano1-8/+9
"git update-ref --stdin" learned to handle transactional updates of symbolic-refs. * kn/update-ref-symref: update-ref: add support for 'symref-update' command reftable: pick either 'oid' or 'target' for new updates update-ref: add support for 'symref-create' command update-ref: add support for 'symref-delete' command update-ref: add support for 'symref-verify' command refs: specify error for regular refs with `old_target` refs: create and use `ref_update_expects_existing_old_ref()`
2024-06-17Merge branch 'ps/ref-storage-migration'Junio C Hamano1-14/+110
A new command has been added to migrate a repository that uses the files backend for its ref storage to use the reftable backend, with limitations. * ps/ref-storage-migration: builtin/refs: new command to migrate ref storage formats refs: implement logic to migrate between ref storage formats refs: implement removal of ref storages worktree: don't store main worktree twice reftable: inline `merged_table_release()` refs/files: fix NULL pointer deref when releasing ref store refs/files: extract function to iterate through root refs refs/files: refactor `add_pseudoref_and_head_entries()` refs: allow to skip creation of reflog entries refs: pass storage format to `ref_store_init()` explicitly refs: convert ref storage format to an enum setup: unset ref storage when reinitializing repository version
2024-06-14global: introduce `USE_THE_REPOSITORY_VARIABLE` macroPatrick Steinhardt1-0/+2
Use of the `the_repository` variable is deprecated nowadays, and we slowly but steadily convert the codebase to not use it anymore. Instead, callers should be passing down the repository to work on via parameters. It is hard though to prove that a given code unit does not use this variable anymore. The most trivial case, merely demonstrating that there is no direct use of `the_repository`, is already a bit of a pain during code reviews as the reviewer needs to manually verify claims made by the patch author. The bigger problem though is that we have many interfaces that implicitly rely on `the_repository`. Introduce a new `USE_THE_REPOSITORY_VARIABLE` macro that allows code units to opt into usage of `the_repository`. The intent of this macro is to demonstrate that a certain code unit does not use this variable anymore, and to keep it from new dependencies on it in future changes, be it explicit or implicit For now, the macro only guards `the_repository` itself as well as `the_hash_algo`. There are many more known interfaces where we have an implicit dependency on `the_repository`, but those are not guarded at the current point in time. Over time though, we should start to add guards as required (or even better, just remove them). Define the macro as required in our code units. As expected, most of our code still relies on the global variable. Nearly all of our builtins rely on the variable as there is no way yet to pass `the_repository` to their entry point. For now, declare the macro in "biultin.h" to keep the required changes at least a little bit more contained. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-14hash: require hash algorithm in `oidread()` and `oidclr()`Patrick Steinhardt1-3/+3
Both `oidread()` and `oidclr()` use `the_repository` to derive the hash function that shall be used. Require callers to pass in the hash algorithm to get rid of this implicit dependency. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-13Merge branch 'ps/ref-storage-migration' into ps/use-the-repositoryJunio C Hamano1-14/+110
* ps/ref-storage-migration: builtin/refs: new command to migrate ref storage formats refs: implement logic to migrate between ref storage formats refs: implement removal of ref storages worktree: don't store main worktree twice reftable: inline `merged_table_release()` refs/files: fix NULL pointer deref when releasing ref store refs/files: extract function to iterate through root refs refs/files: refactor `add_pseudoref_and_head_entries()` refs: allow to skip creation of reflog entries refs: pass storage format to `ref_store_init()` explicitly refs: convert ref storage format to an enum setup: unset ref storage when reinitializing repository version
2024-06-07refs: specify error for regular refs with `old_target`Karthik Nayak1-6/+8
When a reference update tries to update a symref, but the ref in question is actually a regular ref, we raise an error. However the error raised in this situation is: verifying symref target: '<ref>': reference is missing but expected <old-target> which is very generic and doesn't indicate the mismatch of types. Let's make this error more specific: cannot lock ref '<ref>': expected symref with target '<old-target>': but is a regular ref so that users have a clearer understanding. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-07refs: create and use `ref_update_expects_existing_old_ref()`Karthik Nayak1-2/+1
The files and reftable backend, need to check if a ref must exist, so that the required validation can be done. A ref must exist only when the `old_oid` value of the update has been explicitly set and it is not the `null_oid` value. Since we also support symrefs now, we need to ensure that even when `old_target` is set a ref must exist. While this was missed when we added symref support in transactions, there are no active users of this path. As we introduce the 'symref-verify' command in the upcoming commits, it is important to fix this. So let's export this to a function called `ref_update_expects_existing_old_ref()` and expose it internally via 'refs-internal.h'. Helped-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-06refs: implement removal of ref storagesPatrick Steinhardt1-0/+62
We're about to introduce logic to migrate ref storages. One part of the migration will be to delete the files that are part of the old ref storage format. We don't yet have a way to delete such data generically across ref backends though. Implement a new `delete` callback and expose it via a new `ref_storage_delete()` function. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-06refs/files: extract function to iterate through root refsPatrick Steinhardt1-9/+42
Extract a new function that can be used to iterate through all root refs known to the "files" backend. This will be used in the next commit, where we start to teach ref backends to remove themselves. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-06refs/files: refactor `add_pseudoref_and_head_entries()`Patrick Steinhardt1-9/+6
The `add_pseudoref_and_head_entries()` function accepts both the ref store as well as a directory name as input. This is unnecessary though as the ref store already uniquely identifies the root directory of the ref store anyway. Furthermore, the function is misnamed now that we have clarified the meaning of pseudorefs as it doesn't add pseudorefs, but root refs. Rename it accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-06refs: allow to skip creation of reflog entriesPatrick Steinhardt1-0/+4
The ref backends do not have any way to disable the creation of reflog entries. This will be required for upcoming ref format migration logic so that we do not create any entries that didn't exist in the original ref database. Provide a new `REF_SKIP_CREATE_REFLOG` flag that allows the caller to disable reflog entry creation. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-30Merge branch 'ps/refs-without-the-repository-updates'Junio C Hamano1-23/+36
Further clean-up the refs subsystem to stop relying on the_repository, and instead use the repository associated to the ref_store object. * ps/refs-without-the-repository-updates: refs/packed: remove references to `the_hash_algo` refs/files: remove references to `the_hash_algo` refs/files: use correct repository refs: remove `dwim_log()` refs: drop `git_default_branch_name()` refs: pass repo when peeling objects refs: move object peeling into "object.c" refs: pass ref store when detecting dangling symrefs refs: convert iteration over replace refs to accept ref store refs: retrieve worktree ref stores via associated repository refs: refactor `resolve_gitlink_ref()` to accept a repository refs: pass repo when retrieving submodule ref store refs: track ref stores via strmap refs: implement releasing ref storages refs: rename `init_db` callback to avoid confusion refs: adjust names for `init` and `init_db` callbacks
2024-05-28Merge branch 'ps/pseudo-ref-terminology'Junio C Hamano1-2/+1
Terminology to call various ref-like things are getting straightened out. * ps/pseudo-ref-terminology: refs: refuse to write pseudorefs ref-filter: properly distinuish pseudo and root refs refs: pseudorefs are no refs refs: classify HEAD as a root ref refs: do not check ref existence in `is_root_ref()` refs: rename `is_special_ref()` to `is_pseudo_ref()` refs: rename `is_pseudoref()` to `is_root_ref()` Documentation/glossary: define root refs as refs Documentation/glossary: clarify limitations of pseudorefs Documentation/glossary: redefine pseudorefs as special refs
2024-05-23Merge branch 'it/refs-name-conflict'Junio C Hamano1-1/+3
Expose "name conflict" error when a ref creation fails due to D/F conflict in the ref namespace, to improve an error message given by "git fetch". * it/refs-name-conflict: refs: return conflict error when checking packed refs
2024-05-23Merge branch 'ps/pseudo-ref-terminology' into ps/ref-storage-migrationJunio C Hamano1-2/+1
* ps/pseudo-ref-terminology: refs: refuse to write pseudorefs ref-filter: properly distinuish pseudo and root refs refs: pseudorefs are no refs refs: classify HEAD as a root ref refs: do not check ref existence in `is_root_ref()` refs: rename `is_special_ref()` to `is_pseudo_ref()` refs: rename `is_pseudoref()` to `is_root_ref()` Documentation/glossary: define root refs as refs Documentation/glossary: clarify limitations of pseudorefs Documentation/glossary: redefine pseudorefs as special refs
2024-05-23Merge branch 'ps/refs-without-the-repository-updates' into ↵Junio C Hamano1-23/+36
ps/ref-storage-migration * ps/refs-without-the-repository-updates: refs/packed: remove references to `the_hash_algo` refs/files: remove references to `the_hash_algo` refs/files: use correct repository refs: remove `dwim_log()` refs: drop `git_default_branch_name()` refs: pass repo when peeling objects refs: move object peeling into "object.c" refs: pass ref store when detecting dangling symrefs refs: convert iteration over replace refs to accept ref store refs: retrieve worktree ref stores via associated repository refs: refactor `resolve_gitlink_ref()` to accept a repository refs: pass repo when retrieving submodule ref store refs: track ref stores via strmap refs: implement releasing ref storages refs: rename `init_db` callback to avoid confusion refs: adjust names for `init` and `init_db` callbacks
2024-05-17refs/files: remove references to `the_hash_algo`Patrick Steinhardt1-2/+2
Remove references to `the_hash_algo` in favor of the hash algo specified by the repository associated with the files ref store. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17refs/files: use correct repositoryPatrick Steinhardt1-10/+13
There are several places in the "files" backend where we use `the_repository` instead of the repository associated with the ref store itself. Adapt those to use the correct repository. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17refs: implement releasing ref storagesPatrick Steinhardt1-0/+10
Ref storages are typically only initialized once for `the_repository` and then never released. Until now we got away with that without causing memory leaks because `the_repository` stays reachable, and because the ref backend is reachable via `the_repository` its memory basically never leaks. This is about to change though because of the upcoming migration logic, which will create a secondary ref storage. In that case, we will either have to release the old or new ref storage to avoid leaks. Implement a new `release` callback and expose it via a new `ref_storage_release()` function. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17refs: rename `init_db` callback to avoid confusionPatrick Steinhardt1-6/+6
Reference backends have two callbacks `init` and `init_db`. The similarity of these two callbacks has repeatedly confused me whenever I was looking at them, where I always had to look up which of them does what. Rename the `init_db` callback to `create_on_disk`, which should hopefully be clearer. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-17refs: adjust names for `init` and `init_db` callbacksPatrick Steinhardt1-5/+5
The names of the functions that implement the `init` and `init_db` callbacks in the "files" and "packed" backends do not match the names of the callbacks, which is inconsistent. Rename them so that they match, which makes it easier to discover their respective implementations. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-15refs: classify HEAD as a root refPatrick Steinhardt1-2/+1
Root refs are those refs that live in the root of the ref hierarchy. Our old and venerable "HEAD" reference falls into this category, but we don't yet classify it as such in `is_root_ref()`. Adapt the function to also treat "HEAD" as a root ref. This change is safe to do for all current callers: - `ref_kind_from_refname()` already handles "HEAD" explicitly before calling `is_root_ref()`. - The "files" and "reftable" backends explicitly call both `is_root_ref()` and `is_headref()` together. This also aligns behaviour or `is_root_ref()` and `is_headref()` such that we stop checking for ref existence. This changes semantics for our backends: - In the reftable backend we already know that the ref must exist because `is_headref()` is called as part of the ref iterator. The existence check is thus redundant, and the change is safe to do. - In the files backend we use it when populating root refs, where we would skip adding the "HEAD" file if it was not possible to resolve it. The new behaviour is to instead mark "HEAD" as broken, which will cause us to emit warnings in various places. As there are no callers of `is_headref()` left afer the refactoring, we can absorb it completely into `is_root_ref()`. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-15refs: do not check ref existence in `is_root_ref()`Patrick Steinhardt1-2/+2
Before this patch series, root refs except for "HEAD" and our special refs were classified as pseudorefs. Furthermore, our terminology clarified that pseudorefs must not be symbolic refs. This restriction is enforced in `is_root_ref()`, which explicitly checks that a supposed root ref resolves to an object ID without recursing. This has been extremely confusing right from the start because (in old terminology) a ref name may sometimes be a pseudoref and sometimes not depending on whether it is a symbolic or regular ref. This behaviour does not seem reasonable at all and I very much doubt that it results in anything sane. Last but not least, the current behaviour can actually lead to a segfault when calling `is_root_ref()` with a reference that either does not exist or that is a symbolic ref because we never initialized `oid`, but then read it via `is_null_oid()`. We have now changed terminology to clarify that pseudorefs are really only "MERGE_HEAD" and "FETCH_HEAD", whereas all the other refs that live in the root of the ref hierarchy are just plain refs. Thus, we do not need to check whether the ref is symbolic or not. In fact, we can now avoid looking up the ref completely as the name is sufficient for us to figure out whether something would be a root ref or not. This change of course changes semantics for our callers. As there are only three of them we can assess each of them individually: - "ref-filter.c:ref_kind_from_refname()" uses it to classify refs. It's clear that the intent is to classify based on the ref name, only. - "refs/reftable_backend.c:reftable_ref_iterator_advance()" uses it to filter root refs. Again, using existence checks is pointless here as the iterator has just surfaced the ref, so we know it does exist. - "refs/files_backend.c:add_pseudoref_and_head_entries()" uses it to determine whether it should add a ref to the root directory of its iterator. This had the effect that we skipped over any files that are either a symbolic ref, or which are not a ref at all. The new behaviour is to include symbolic refs know, which aligns us with the adapted terminology. Furthermore, files which look like root refs but aren't are now mark those as "broken". As broken refs are not surfaced by our tooling, this should not lead to a change in user-visible behaviour, but may cause us to emit warnings. This feels like the right thing to do as we would otherwise just silently ignore corrupted root refs completely. So in all cases the existence check was either superfluous, not in line with the adapted terminology or masked potential issues. This commit thus changes the behaviour as proposed and drops the existence check altogether. Add a test that verifies that this does not change user-visible behaviour. Namely, we still don't want to show broken refs to the user by default in git-for-each-ref(1). What this does allow though is for internal callers to surface dangling root refs when they pass in the `DO_FOR_EACH_INCLUDE_BROKEN` flag. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-15refs: rename `is_pseudoref()` to `is_root_ref()`Patrick Steinhardt1-1/+1
Rename `is_pseudoref()` to `is_root_ref()` to adapt to the newly defined terminology in our gitglossary(7). Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-07refs: remove `create_symref` and associated dead codeKarthik Nayak1-67/+0
In the previous commits, we converted `refs_create_symref()` to utilize transactions to perform symref updates. Earlier `refs_create_symref()` used `create_symref()` to do the same. We can now remove `create_symref()` and any code associated with it which is no longer used. We remove `create_symref()` code from all the reference backends and also remove it entirely from the `ref_storage_be` struct. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-07refs: add support for transactional symref updatesKarthik Nayak1-21/+92
The reference backends currently support transactional reference updates. While this is exposed to users via 'git-update-ref' and its '--stdin' mode, it is also used internally within various commands. However, we do not support transactional updates of symrefs. This commit adds support for symrefs in both the 'files' and the 'reftable' backend. Here, we add and use `ref_update_has_null_new_value()`, a helper function which is used to check if there is a new_value in a reference update. The new value could either be a symref target `new_target` or a OID `new_oid`. We also add another common function `ref_update_check_old_target` which will be used to check if the update's old_target corresponds to a reference's current target. Now transactional updates (verify, create, delete, update) can be used for: - regular refs - symbolic refs - conversion of regular to symbolic refs and vice versa This also allows us to expose this to users via new commands in 'git-update-ref' in the future. Note that a dangling symref update does not record a new reflog entry, which is unchanged before and after this commit. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-07refs: move `original_update_refname` to 'refs.c'Karthik Nayak1-16/+5
The files backend and the reftable backend implement `original_update_refname` to obtain the original refname of the update. Move it out to 'refs.c' and only expose it internally to the refs library. This will be used in an upcoming commit to also introduce another common functionality for the two backends. We also rename the function to `ref_update_original_update_refname` to keep it consistent with the upcoming other 'ref_update_*' functions that'll be introduced. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-07files-backend: extract out `create_symref_lock()`Karthik Nayak1-14/+37
The function `create_symref_locked()` creates a symref by creating a '<symref>.lock' file and then committing the symref lock, which creates the final symref. Extract the early half of `create_symref_locked()` into a new helper function `create_symref_lock()`. Because the name of the new function is too similar to the original, rename the original to `create_and_commit_symref()` to avoid confusion. The new function `create_symref_locked()` can be used to create the symref lock in a separate step from that of committing it. This allows to add transactional support for symrefs, where the lock would be created in the preparation step and the lock would be committed in the finish step. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-07refs: accept symref values in `ref_transaction_update()`Karthik Nayak1-6/+6
The function `ref_transaction_update()` obtains ref information and flags to create a `ref_update` and add them to the transaction at hand. To extend symref support in transactions, we need to also accept the old and new ref targets and process it. This commit adds the required parameters to the function and modifies all call sites. The two parameters added are `new_target` and `old_target`. The `new_target` is used to denote what the reference should point to when the transaction is applied. Some functions allow this parameter to be NULL, meaning that the reference is not changed. The `old_target` denotes the value the reference must have before the update. Some functions allow this parameter to be NULL, meaning that the old value of the reference is not checked. We also update the internal function `ref_transaction_add_update()` similarly to take the two new parameters. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-06refs: return conflict error when checking packed refsIvan Tse1-1/+3
The TRANSACTION_NAME_CONFLICT error code refers to a failure to create a ref due to a name conflict with another ref. An example of this is a directory/file conflict such as ref names A/B and A. "git fetch" uses this error code to more accurately describe the error by recommending to the user that they try running "git remote prune" to remove any old refs that are deleted by the remote which would clear up any directory/file conflicts. This helpful error message is not displayed when the conflicted ref is stored in packed refs. This change fixes this by ensuring error return code consistency in `lock_raw_ref`. Signed-off-by: Ivan Tse <ivan.tse1@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-03-05Merge branch 'kn/for-all-refs'Junio C Hamano1-34/+93
"git for-each-ref" learned "--include-root-refs" option to show even the stuff outside the 'refs/' hierarchy. * kn/for-all-refs: for-each-ref: add new option to include root refs ref-filter: rename 'FILTER_REFS_ALL' to 'FILTER_REFS_REGULAR' refs: introduce `refs_for_each_include_root_refs()` refs: extract out `loose_fill_ref_dir_regular_file()` refs: introduce `is_pseudoref()` and `is_headref()`
2024-02-23refs: introduce `refs_for_each_include_root_refs()`Karthik Nayak1-5/+60
Introduce a new ref iteration flag `DO_FOR_EACH_INCLUDE_ROOT_REFS`, which will be used to iterate over regular refs plus pseudorefs and HEAD. Refs which fall outside the `refs/` and aren't either pseudorefs or HEAD are more of a grey area. This is because we don't block the users from creating such refs but they are not officially supported. Introduce `refs_for_each_include_root_refs()` which calls `do_for_each_ref()` with this newly introduced flag. In `refs/files-backend.c`, introduce a new function `add_pseudoref_and_head_entries()` to add pseudorefs and HEAD to the `ref_dir`. We then finally call `add_pseudoref_and_head_entries()` whenever the `DO_FOR_EACH_INCLUDE_ROOT_REFS` flag is set. Any new ref backend will also have to implement similar changes on its end. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-23refs: extract out `loose_fill_ref_dir_regular_file()`Karthik Nayak1-29/+33
Extract out the code for adding a single file to the loose ref dir as `loose_fill_ref_dir_regular_file()` from `loose_fill_ref_dir()` in `refs/files-backend.c`. This allows us to use this function independently in the following commits where we add code to also add pseudorefs to the ref dir. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-21refs: stop resolving ref corresponding to reflogsPatrick Steinhardt1-10/+2
The reflog iterator tries to resolve the corresponding ref for every reflog that it is about to yield. Historically, this was done due to multiple reasons: - It ensures that the refname is safe because we end up calling `check_refname_format()`. Also, non-conformant refnames are skipped altogether. - The iterator used to yield the resolved object ID as well as its flags to the callback. This info was never used though, and the corresponding parameters were dropped in the preceding commit. - When a ref is corrupt then the reflog is not emitted at all. We're about to introduce a new `git reflog list` subcommand that will print all reflogs that the refdb knows about. Skipping over reflogs whose refs are corrupted would be quite counterproductive in this case as the user would have no way to learn about reflogs which may still exist in their repository to help and rescue such a corrupted ref. Thus, the only remaining reason for why we'd want to resolve the ref is to verify its refname. Refactor the code to call `check_refname_format()` directly instead of trying to resolve the ref. This is significantly more efficient given that we don't have to hit the object database anymore to list reflogs. And second, it ensures that we end up showing reflogs of broken refs, which will help to make the reflog more useful. Note that this really only impacts the case where the corresponding ref is corrupt. Reflogs for nonexistent refs would have been returned to the caller beforehand already as we did not pass `RESOLVE_REF_READING` to the function, and thus `refs_resolve_ref_unsafe()` would have returned successfully in that case. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-21refs: drop unused params from the reflog iterator callbackPatrick Steinhardt1-7/+1
The ref and reflog iterators share much of the same underlying code to iterate over the corresponding entries. This results in some weird code because the reflog iterator also exposes an object ID as well as a flag to the callback function. Neither of these fields do refer to the reflog though -- they refer to the corresponding ref with the same name. This is quite misleading. In practice at least the object ID cannot really be implemented in any other way as a reflog does not have a specific object ID in the first place. This is further stressed by the fact that none of the callbacks except for our test helper make use of these fields. Split up the infrastucture so that ref and reflog iterators use separate callback signatures. This allows us to drop the nonsensical fields from the reflog iterator. Note that internally, the backends still use the same shared infra to iterate over both types. As the backends should never end up being called directly anyway, this is not much of a problem and thus kept as-is for simplicity's sake. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-21refs: always treat iterators as orderedPatrick Steinhardt1-4/+3
In the preceding commit we have converted the reflog iterator of the "files" backend to be ordered, which was the only remaining ref iterator that wasn't ordered. Refactor the ref iterator infrastructure so that we always assume iterators to be ordered, thus simplifying the code. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-21refs/files: sort merged worktree and common reflogsPatrick Steinhardt1-28/+2
When iterating through reflogs in a worktree we create a merged iterator that merges reflogs from both refdbs. The resulting refs are ordered so that instead we first return all worktree reflogs before we return all common refs. This is the only remaining case where a ref iterator returns entries in a non-lexicographic order. The result would look something like the following (listed with a command we introduce in a subsequent commit): ``` $ git reflog list HEAD refs/worktree/per-worktree refs/heads/main refs/heads/wt ``` So we first print the per-worktree reflogs in lexicographic order, then the common reflogs in lexicographic order. This is confusing and not consistent with how we print per-worktree refs, which are exclusively sorted lexicographically. Sort reflogs lexicographically in the same way as we sort normal refs. As this is already implemented properly by the "reftable" backend via a separate selection function, we simply pull out that logic and reuse it for the "files" backend. As logs are properly sorted now, mark the merged reflog iterator as sorted. Tests will be added in a subsequent commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-21refs/files: sort reflogs returned by the reflog iteratorPatrick Steinhardt1-2/+2
We use a directory iterator to return reflogs via the reflog iterator. This iterator returns entries in the same order as readdir(3P) would and will thus yield reflogs with no discernible order. Set the new `DIR_ITERATOR_SORTED` flag that was introduced in the preceding commit so that the order is deterministic. While the effect of this can only been observed in a test tool, a subsequent commit will start to expose this functionality to users via a new `git reflog list` subcommand. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-26Merge branch 'ps/worktree-refdb-initialization'Junio C Hamano1-6/+31
Instead of manually creating refs/ hierarchy on disk upon a creation of a secondary worktree, which is only usable via the files backend, use the refs API to populate it. * ps/worktree-refdb-initialization: builtin/worktree: create refdb via ref backend worktree: expose interface to look up worktree by name builtin/worktree: move setup of commondir file earlier refs/files: skip creation of "refs/{heads,tags}" for worktrees setup: move creation of "refs/" into the files backend refs: prepare `refs_init_db()` for initializing worktree refs
2024-01-16Merge branch 'ps/refstorage-extension'Junio C Hamano1-1/+0
Introduce a new extension "refstorage" so that we can mark a repository that uses a non-default ref backend, like reftable. * ps/refstorage-extension: t9500: write "extensions.refstorage" into config builtin/clone: introduce `--ref-format=` value flag builtin/init: introduce `--ref-format=` value flag builtin/rev-parse: introduce `--show-ref-format` flag t: introduce GIT_TEST_DEFAULT_REF_FORMAT envvar setup: introduce GIT_DEFAULT_REF_FORMAT envvar setup: introduce "extensions.refStorage" extension setup: set repository's formats on init setup: start tracking ref storage format refs: refactor logic to look up storage backends worktree: skip reading HEAD when repairing worktrees t: introduce DEFAULT_REPO_FORMAT prereq
2024-01-08Merge branch 'en/header-cleanup'Junio C Hamano1-2/+0
Remove unused header "#include". * en/header-cleanup: treewide: remove unnecessary includes in source files treewide: add direct includes currently only pulled in transitively trace2/tr2_tls.h: remove unnecessary include submodule-config.h: remove unnecessary include pkt-line.h: remove unnecessary include line-log.h: remove unnecessary include http.h: remove unnecessary include fsmonitor--daemon.h: remove unnecessary includes blame.h: remove unnecessary includes archive.h: remove unnecessary include treewide: remove unnecessary includes in source files treewide: remove unnecessary includes from header files
2024-01-08refs/files: skip creation of "refs/{heads,tags}" for worktreesPatrick Steinhardt1-8/+14
The files ref backend will create both "refs/heads" and "refs/tags" in the Git directory. While this logic makes sense for normal repositories, it does not for worktrees because those refs are "common" refs that would always be contained in the main repository's ref database. Introduce a new flag telling the backend that it is expected to create a per-worktree ref database and skip creation of these dirs in the files backend when the flag is set. No other backends (currently) need worktree-specific logic, so this is the only required change to start creating per-worktree ref databases via `refs_init_db()`. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-08setup: move creation of "refs/" into the files backendPatrick Steinhardt1-0/+17
When creating the ref database we unconditionally create the "refs/" directory in "setup.c". This is a mandatory prerequisite for all Git repositories regardless of the ref backend in use, because Git will be unable to detect the directory as a repository if "refs/" doesn't exist. We are about to add another new caller that will want to create a ref database when creating worktrees. We would require the same logic to create the "refs/" directory even though the caller really should not care about such low-level details. Ideally, the ref database should be fully initialized after calling `refs_init_db()`. Move the code to create the directory into the files backend itself to make it so. This means that future ref backends will also need to have equivalent logic around to ensure that the directory exists, but it seems a lot more sensible to have it this way round than to require callers to create the directory themselves. An alternative to this would be to create "refs/" in `refs_init_db()` directly. This feels conceptually unclean though as the creation of the refdb is now cluttered across different callsites. Furthermore, both the "files" and the upcoming "reftable" backend write backend-specific data into the "refs/" directory anyway, so splitting up this logic would only make it harder to reason about. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-08refs: prepare `refs_init_db()` for initializing worktree refsPatrick Steinhardt1-1/+3
The purpose of `refs_init_db()` is to initialize the on-disk files of a new ref database. The function is quite inflexible right now though, as callers can neither specify the `struct ref_store` nor can they pass any flags. Refactor the interface to accept both of these. This will be required so that we can start initializing per-worktree ref databases via the ref backend instead of open-coding the initialization in "worktree.c". Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-02refs: refactor logic to look up storage backendsPatrick Steinhardt1-1/+0
In order to look up ref storage backends, we're currently using a linked list of backends, where each backend is expected to set up its `next` pointer to the next ref storage backend. This is kind of a weird setup as backends need to be aware of other backends without much of a reason. Refactor the code so that the array of backends is centrally defined in "refs.c", where each backend is now identified by an integer constant. Expose functions to translate from those integer constants to the name and vice versa, which will be required by subsequent patches. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-12-26treewide: remove unnecessary includes in source filesElijah Newren1-2/+0
Each of these were checked with gcc -E -I. ${SOURCE_FILE} | grep ${HEADER_FILE} to ensure that removing the direct inclusion of the header actually resulted in that header no longer being included at all (i.e. that no other header pulled it in transitively). ...except for a few cases where we verified that although the header was brought in transitively, nothing from it was directly used in that source file. These cases were: * builtin/credential-cache.c * builtin/pull.c * builtin/send-pack.c Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-11-17refs: remove `delete_refs` callback from backendsPatrick Steinhardt1-7/+0
Now that `refs_delete_refs` is implemented in a generic way via the ref transaction interfaces there are no callers left that invoke the `delete_refs` callback anymore. Remove it from all of our backends. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-11-17refs: deduplicate code to delete referencesPatrick Steinhardt1-45/+1
Both the files and the packed-refs reference backends now use the same generic transactions-based code to delete references. Let's pull these implementations up into `refs_delete_refs()` to deduplicate the code. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-11-17refs/files: use transactions to delete referencesPatrick Steinhardt1-32/+34
In the `files_delete_refs()` callback function of the files backend we implement deletion of references. This is done in two steps: 1. We lock the packed-refs file and delete all references from it in a single transaction. 2. We delete all loose references via separate calls to `refs_delete_ref()`. These steps essentially duplicate the logic around locking and deletion order that we already have in the transactional interfaces, where we do know to lock and evict references from the packed-refs file. Despite the fact that we duplicate the logic, it's also less efficient than if we used a single generic transaction: - The transactional interface knows to skip locking of the packed refs in case they don't contain any of the refs which are about to be deleted. - We end up creating N+1 separate reference transactions, one for the packed-refs file and N for the individual loose references. Refactor the code to instead delete references via a single transaction. As we don't assert the expected old object ID this is equivalent to the previous behaviour, and we already do the same in the packed-refs backend. Despite the fact that the result is simpler to reason about, this change also results in improved performance. The following benchmarks have been executed in linux.git: ``` $ hyperfine -n '{rev}, packed={packed} refcount={refcount}' \ -L packed true,false -L refcount 1,1000 -L rev master,pks-ref-store-generic-delete-refs \ --setup 'git -C /home/pks/Development/git switch --detach {rev} && make -C /home/pks/Development/git -j17' \ --prepare 'printf "create refs/heads/new-branch-%d HEAD\n" $(seq {refcount}) | git -C /home/pks/Reproduction/linux.git update-ref --stdin && if test {packed} = true; then git pack-refs --all; fi' \ --warmup=10 \ '/home/pks/Development/git/bin-wrappers/git -C /home/pks/Reproduction/linux.git branch -d new-branch-{1..{refcount}}' Benchmark 1: master packed=true refcount=1 Time (mean ± σ): 7.8 ms ± 1.6 ms [User: 3.4 ms, System: 4.4 ms] Range (min … max): 5.5 ms … 11.0 ms 120 runs Benchmark 2: master packed=false refcount=1 Time (mean ± σ): 7.0 ms ± 1.1 ms [User: 3.2 ms, System: 3.8 ms] Range (min … max): 5.7 ms … 9.8 ms 180 runs Benchmark 3: master packed=true refcount=1000 Time (mean ± σ): 283.8 ms ± 5.2 ms [User: 45.7 ms, System: 231.5 ms] Range (min … max): 276.7 ms … 291.6 ms 10 runs Benchmark 4: master packed=false refcount=1000 Time (mean ± σ): 284.4 ms ± 5.3 ms [User: 44.2 ms, System: 233.6 ms] Range (min … max): 277.1 ms … 293.3 ms 10 runs Benchmark 5: generic-delete-refs packed=true refcount=1 Time (mean ± σ): 6.2 ms ± 1.8 ms [User: 2.3 ms, System: 3.9 ms] Range (min … max): 4.1 ms … 12.2 ms 142 runs Benchmark 6: generic-delete-refs packed=false refcount=1 Time (mean ± σ): 7.1 ms ± 1.4 ms [User: 2.8 ms, System: 4.3 ms] Range (min … max): 4.2 ms … 10.8 ms 157 runs Benchmark 7: generic-delete-refs packed=true refcount=1000 Time (mean ± σ): 198.9 ms ± 1.7 ms [User: 29.5 ms, System: 165.7 ms] Range (min … max): 196.1 ms … 201.4 ms 10 runs Benchmark 8: generic-delete-refs packed=false refcount=1000 Time (mean ± σ): 199.7 ms ± 7.8 ms [User: 32.2 ms, System: 163.2 ms] Range (min … max): 193.8 ms … 220.7 ms 10 runs Summary generic-delete-refs packed=true refcount=1 ran 1.14 ± 0.37 times faster than master packed=false refcount=1 1.15 ± 0.40 times faster than generic-delete-refs packed=false refcount=1 1.26 ± 0.44 times faster than master packed=true refcount=1 32.24 ± 9.17 times faster than generic-delete-refs packed=true refcount=1000 32.36 ± 9.29 times faster than generic-delete-refs packed=false refcount=1000 46.00 ± 13.10 times faster than master packed=true refcount=1000 46.10 ± 13.13 times faster than master packed=false refcount=1000 ``` Especially in the case where we have many references we can see a clear performance speedup of nearly 30%. This is in contrast to the stated objecive in a27dcf89b68 (refs: make delete_refs() virtual, 2016-09-04), where the virtual `delete_refs()` function was introduced with the intent to speed things up rather than making things slower. So it seems like we have outlived the need for a virtual function. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>