From da80429cef00ff697bb42ba6a935bc56b8a386c7 Mon Sep 17 00:00:00 2001 From: Jonathan Tan Date: Fri, 1 Nov 2024 13:11:45 -0700 Subject: [PATCH 1/4] t0410: make test description clearer Commit 9a4c507886 (t0410: test fetching from many promisor remotes, 2019-06-25) adds some tests that demonstrate not the automatic fetching of missing objects, but the direct fetching from another promisor remote (configured explicitly in one test and implicitly via --filter on the "git fetch" CLI invocation in the other test) - thus demonstrating support for multiple promisor remotes, as described in the commit message. Change the test descriptions accordingly to make this clearer. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano --- t/t0410-partial-clone.sh | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh index 818700fbecd457..eadb69473f4293 100755 --- a/t/t0410-partial-clone.sh +++ b/t/t0410-partial-clone.sh @@ -241,7 +241,7 @@ test_expect_success 'fetching of missing objects works with ref-in-want enabled' grep "fetch< fetch=.*ref-in-want" trace ' -test_expect_success 'fetching of missing objects from another promisor remote' ' +test_expect_success 'fetching from another promisor remote' ' git clone "file://$(pwd)/server" server2 && test_commit -C server2 bar && git -C server2 repack -a -d --write-bitmap-index && @@ -264,7 +264,7 @@ test_expect_success 'fetching of missing objects from another promisor remote' ' grep "$HASH2" out ' -test_expect_success 'fetching of missing objects configures a promisor remote' ' +test_expect_success 'fetching with --filter configures a promisor remote' ' git clone "file://$(pwd)/server" server3 && test_commit -C server3 baz && git -C server3 repack -a -d --write-bitmap-index && From 78995ff57c6a8713f198fecc03cf5a6e530af45c Mon Sep 17 00:00:00 2001 From: Jonathan Tan Date: Fri, 1 Nov 2024 13:11:46 -0700 Subject: [PATCH 2/4] t0410: use from-scratch server A subsequent commit will add functionality: when fetching from a promisor remote, existing non-promisor objects that are ancestors of any fetched object will be repacked into promisor packs (since if a promisor remote has an object, it also has all its ancestors). This means that sometimes, a fetch from a promisor remote results in 2 new promisor packs (instead of the 1 that you would expect). There is a test that fetches a descendant of a local object from a promisor remote, but also specifically tests that there is exactly 1 promisor pack as a result of the fetch. This means that this test will fail when the subsequent commit is added. Since the ancestry of the fetched object is not the concern of this test, make the fetched objects have no ancestry in common with the objets in the client repo. This is done by making the server from scratch, instead of using an existing repo that has objects in common with the client. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano --- t/t0410-partial-clone.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh index eadb69473f4293..e2b317db650b24 100755 --- a/t/t0410-partial-clone.sh +++ b/t/t0410-partial-clone.sh @@ -265,7 +265,7 @@ test_expect_success 'fetching from another promisor remote' ' ' test_expect_success 'fetching with --filter configures a promisor remote' ' - git clone "file://$(pwd)/server" server3 && + test_create_repo server3 && test_commit -C server3 baz && git -C server3 repack -a -d --write-bitmap-index && HASH3=$(git -C server3 rev-parse baz) && From d9e24ce2ca07db19eec6af332a7244eafbd82f67 Mon Sep 17 00:00:00 2001 From: Jonathan Tan Date: Fri, 1 Nov 2024 13:11:47 -0700 Subject: [PATCH 3/4] t5300: move --window clamp test next to unclamped A subsequent commit will change the behavior of "git index-pack --promisor", which is exercised in "build pack index for an existing pack", causing the unclamped and clamped versions of the --window test to exhibit different behavior. Move the clamp test closer to the unclamped test that it references. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano --- t/t5300-pack-object.sh | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh index 3b9dae331a5ea9..aff164ddf8ec79 100755 --- a/t/t5300-pack-object.sh +++ b/t/t5300-pack-object.sh @@ -156,6 +156,11 @@ test_expect_success 'pack without delta' ' check_deltas stderr = 0 ' +test_expect_success 'negative window clamps to 0' ' + git pack-objects --progress --window=-1 neg-window stderr && + check_deltas stderr = 0 +' + test_expect_success 'pack-objects with bogus arguments' ' test_must_fail git pack-objects --window=0 test-1 blah blah stderr && - check_deltas stderr = 0 -' - for hash in sha1 sha256 do test_expect_success "verify-pack with $hash packfile" ' From 705e624f96c085ad4d0fff5c8ca31c38ec6c8b32 Mon Sep 17 00:00:00 2001 From: Jonathan Tan Date: Fri, 1 Nov 2024 13:11:48 -0700 Subject: [PATCH 4/4] index-pack: repack local links into promisor packs Teach index-pack to, when processing the objects in a pack with --promisor specified on the CLI, repack local objects (and the local objects that they refer to, recursively) referenced by these objects into promisor packs. This prevents the situation in which, when fetching from a promisor remote, we end up with promisor objects (newly fetched) referring to non-promisor objects (locally created prior to the fetch). This situation may arise if the client had previously pushed objects to the remote, for example. One issue that arises in this situation is that, if the non-promisor objects become inaccessible except through promisor objects (for example, if the branch pointing to them has moved to point to the promisor object that refers to them), then GC will garbage collect them. There are other ways to solve this, but the simplest seems to be to enforce the invariant that we don't have promisor objects referring to non-promisor objects. This repacking is done from index-pack to minimize the performance impact. During a fetch, the only time most objects are fully inflated in memory is when their object ID is computed, so we also scan the objects (to see which objects they refer to) during this time. Also to minimize the performance impact, an object is calculated to be local if it's a loose object or present in a non-promisor pack. (If it's also in a promisor pack or referred to by an object in a promisor pack, it is technically already a promisor object. But a misidentification of a promisor object as a non-promisor object is relatively benign here - we will thus repack that promisor object into a promisor pack, duplicating it in the object store, but there is no correctness issue, just an issue of inefficiency.) Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano --- Documentation/git-index-pack.txt | 5 ++ builtin/index-pack.c | 110 ++++++++++++++++++++++++++++++- builtin/pack-objects.c | 28 ++++++++ t/t5616-partial-clone.sh | 30 +++++++++ 4 files changed, 171 insertions(+), 2 deletions(-) diff --git a/Documentation/git-index-pack.txt b/Documentation/git-index-pack.txt index 5a20deefd5f5da..4be09e58e72145 100644 --- a/Documentation/git-index-pack.txt +++ b/Documentation/git-index-pack.txt @@ -139,6 +139,11 @@ include::object-format-disclaimer.txt[] written. If a `` is provided, then that content will be written to the .promisor file for future reference. See link:technical/partial-clone.html[partial clone] for more information. ++ +Also, if there are objects in the given pack that references non-promisor +objects (in the repo), repacks those non-promisor objects into a promisor +pack. This avoids a situation in which a repo has non-promisor objects that are +accessible through promisor objects. NOTES ----- diff --git a/builtin/index-pack.c b/builtin/index-pack.c index 9d23b41b3a2306..e4afd6725f5ac1 100644 --- a/builtin/index-pack.c +++ b/builtin/index-pack.c @@ -9,6 +9,7 @@ #include "csum-file.h" #include "blob.h" #include "commit.h" +#include "tag.h" #include "tree.h" #include "progress.h" #include "fsck.h" @@ -20,9 +21,14 @@ #include "object-file.h" #include "object-store-ll.h" #include "oid-array.h" +#include "oidset.h" +#include "path.h" #include "replace-object.h" +#include "tree-walk.h" #include "promisor-remote.h" +#include "run-command.h" #include "setup.h" +#include "strvec.h" static const char index_pack_usage[] = "git index-pack [-v] [-o ] [--keep | --keep=] [--[no-]rev-index] [--verify] [--strict[==...]] [--fsck-objects[==...]] ( | --stdin [--fix-thin] [])"; @@ -148,6 +154,13 @@ static uint32_t input_crc32; static int input_fd, output_fd; static const char *curr_pack; +/* + * local_links is guarded by read_mutex, and record_local_links is read-only in + * a thread. + */ +static struct oidset local_links = OIDSET_INIT; +static int record_local_links; + static struct thread_local *thread_data; static int nr_dispatched; static int threads_active; @@ -799,6 +812,44 @@ static int check_collison(struct object_entry *entry) return 0; } +static void record_if_local_object(const struct object_id *oid) +{ + struct object_info info = OBJECT_INFO_INIT; + if (oid_object_info_extended(the_repository, oid, &info, 0)) + /* Missing; assume it is a promisor object */ + return; + if (info.whence == OI_PACKED && info.u.packed.pack->pack_promisor) + return; + oidset_insert(&local_links, oid); +} + +static void do_record_local_links(struct object *obj) +{ + if (obj->type == OBJ_TREE) { + struct tree *tree = (struct tree *)obj; + struct tree_desc desc; + struct name_entry entry; + if (init_tree_desc_gently(&desc, &tree->object.oid, + tree->buffer, tree->size, 0)) + /* + * Error messages are given when packs are + * verified, so do not print any here. + */ + return; + while (tree_entry_gently(&desc, &entry)) + record_if_local_object(&entry.oid); + } else if (obj->type == OBJ_COMMIT) { + struct commit *commit = (struct commit *) obj; + struct commit_list *parents = commit->parents; + + for (; parents; parents = parents->next) + record_if_local_object(&parents->item->object.oid); + } else if (obj->type == OBJ_TAG) { + struct tag *tag = (struct tag *) obj; + record_if_local_object(get_tagged_oid(tag)); + } +} + static void sha1_object(const void *data, struct object_entry *obj_entry, unsigned long size, enum object_type type, const struct object_id *oid) @@ -845,7 +896,7 @@ static void sha1_object(const void *data, struct object_entry *obj_entry, free(has_data); } - if (strict || do_fsck_object) { + if (strict || do_fsck_object || record_local_links) { read_lock(); if (type == OBJ_BLOB) { struct blob *blob = lookup_blob(the_repository, oid); @@ -877,6 +928,8 @@ static void sha1_object(const void *data, struct object_entry *obj_entry, die(_("fsck error in packed object")); if (strict && fsck_walk(obj, NULL, &fsck_options)) die(_("Not all child objects of %s are reachable"), oid_to_hex(&obj->oid)); + if (record_local_links) + do_record_local_links(obj); if (obj->type == OBJ_TREE) { struct tree *item = (struct tree *) obj; @@ -1719,6 +1772,57 @@ static void show_pack_info(int stat_only) free(chain_histogram); } +static void repack_local_links(void) +{ + struct child_process cmd = CHILD_PROCESS_INIT; + FILE *out; + struct strbuf line = STRBUF_INIT; + struct oidset_iter iter; + struct object_id *oid; + char *base_name; + + if (!oidset_size(&local_links)) + return; + + base_name = mkpathdup("%s/pack/pack", repo_get_object_directory(the_repository)); + + strvec_push(&cmd.args, "pack-objects"); + strvec_push(&cmd.args, "--exclude-promisor-objects-best-effort"); + strvec_push(&cmd.args, base_name); + cmd.git_cmd = 1; + cmd.in = -1; + cmd.out = -1; + if (start_command(&cmd)) + die(_("could not start pack-objects to repack local links")); + + oidset_iter_init(&local_links, &iter); + while ((oid = oidset_iter_next(&iter))) { + if (write_in_full(cmd.in, oid_to_hex(oid), the_hash_algo->hexsz) < 0 || + write_in_full(cmd.in, "\n", 1) < 0) + die(_("failed to feed local object to pack-objects")); + } + close(cmd.in); + + out = xfdopen(cmd.out, "r"); + while (strbuf_getline_lf(&line, out) != EOF) { + unsigned char binary[GIT_MAX_RAWSZ]; + if (line.len != the_hash_algo->hexsz || + !hex_to_bytes(binary, line.buf, line.len)) + die(_("index-pack: Expecting full hex object ID lines only from pack-objects.")); + + /* + * pack-objects creates the .pack and .idx files, but not the + * .promisor file. Create the .promisor file, which is empty. + */ + write_special_file("promisor", "", NULL, binary, NULL); + } + + fclose(out); + if (finish_command(&cmd)) + die(_("could not finish pack-objects to repack local links")); + strbuf_release(&line); +} + int cmd_index_pack(int argc, const char **argv, const char *prefix, @@ -1794,7 +1898,7 @@ int cmd_index_pack(int argc, } else if (skip_to_optional_arg(arg, "--keep", &keep_msg)) { ; /* nothing to do */ } else if (skip_to_optional_arg(arg, "--promisor", &promisor_msg)) { - ; /* already parsed */ + record_local_links = 1; } else if (starts_with(arg, "--threads=")) { char *end; nr_threads = strtoul(arg+10, &end, 0); @@ -1970,6 +2074,8 @@ int cmd_index_pack(int argc, free((void *) curr_index); free(curr_rev_index); + repack_local_links(); + /* * Let the caller know this pack is not self contained */ diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c index 080071426710da..762949e4c8f73c 100644 --- a/builtin/pack-objects.c +++ b/builtin/pack-objects.c @@ -239,6 +239,7 @@ static enum { static uint16_t write_bitmap_options = BITMAP_OPT_HASH_CACHE; static int exclude_promisor_objects; +static int exclude_promisor_objects_best_effort; static int use_delta_islands; @@ -4312,6 +4313,18 @@ static int option_parse_cruft_expiration(const struct option *opt UNUSED, return 0; } +static int is_not_in_promisor_pack_obj(struct object *obj, void *data UNUSED) +{ + struct object_info info = OBJECT_INFO_INIT; + if (oid_object_info_extended(the_repository, &obj->oid, &info, 0)) + BUG("should_include_obj should only be called on existing objects"); + return info.whence != OI_PACKED || !info.u.packed.pack->pack_promisor; +} + +static int is_not_in_promisor_pack(struct commit *commit, void *data) { + return is_not_in_promisor_pack_obj((struct object *) commit, data); +} + int cmd_pack_objects(int argc, const char **argv, const char *prefix, @@ -4424,6 +4437,9 @@ int cmd_pack_objects(int argc, option_parse_missing_action), OPT_BOOL(0, "exclude-promisor-objects", &exclude_promisor_objects, N_("do not pack objects in promisor packfiles")), + OPT_BOOL(0, "exclude-promisor-objects-best-effort", + &exclude_promisor_objects_best_effort, + N_("implies --missing=allow-any")), OPT_BOOL(0, "delta-islands", &use_delta_islands, N_("respect islands during delta compression")), OPT_STRING_LIST(0, "uri-protocol", &uri_protocols, @@ -4504,10 +4520,18 @@ int cmd_pack_objects(int argc, strvec_push(&rp, "--unpacked"); } + if (exclude_promisor_objects && exclude_promisor_objects_best_effort) + die(_("options '%s' and '%s' cannot be used together"), + "--exclude-promisor-objects", "--exclude-promisor-objects-best-effort"); if (exclude_promisor_objects) { use_internal_rev_list = 1; fetch_if_missing = 0; strvec_push(&rp, "--exclude-promisor-objects"); + } else if (exclude_promisor_objects_best_effort) { + use_internal_rev_list = 1; + fetch_if_missing = 0; + option_parse_missing_action(NULL, "allow-any", 0); + /* revs configured below */ } if (unpack_unreachable || keep_unreachable || pack_loose_unreachable) use_internal_rev_list = 1; @@ -4627,6 +4651,10 @@ int cmd_pack_objects(int argc, repo_init_revisions(the_repository, &revs, NULL); list_objects_filter_copy(&revs.filter, &filter_options); + if (exclude_promisor_objects_best_effort) { + revs.include_check = is_not_in_promisor_pack; + revs.include_check_obj = is_not_in_promisor_pack_obj; + } get_object_list(&revs, rp.nr, rp.v); release_revisions(&revs); } diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh index c53e93be2f7779..91d1808883615f 100755 --- a/t/t5616-partial-clone.sh +++ b/t/t5616-partial-clone.sh @@ -694,6 +694,36 @@ test_expect_success 'lazy-fetch in submodule succeeds' ' git -C client restore --recurse-submodules --source=HEAD^ :/ ' +test_expect_success 'after fetching descendants of non-promisor commits, gc works' ' + # Setup + git init full && + git -C full config uploadpack.allowfilter 1 && + git -C full config uploadpack.allowanysha1inwant 1 && + touch full/foo && + git -C full add foo && + git -C full commit -m "commit 1" && + git -C full checkout --detach && + + # Partial clone and push commit to remote + git clone "file://$(pwd)/full" --filter=blob:none partial && + echo "hello" > partial/foo && + git -C partial commit -a -m "commit 2" && + git -C partial push && + + # gc in partial repo + git -C partial gc --prune=now && + + # Create another commit in normal repo + git -C full checkout main && + echo " world" >> full/foo && + git -C full commit -a -m "commit 3" && + + # Pull from remote in partial repo, and run gc again + git -C partial pull && + git -C partial gc --prune=now +' + + . "$TEST_DIRECTORY"/lib-httpd.sh start_httpd