@matheusbsbs / matheus-bagliano / commits / ecd81dfc79

tmp-objdir: disable ref updates when replacing the primary odb

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>

Neeraj Singh committed Dec 6, 2021 at 22:05 UTC ecd81dfc79cf12cc21fc0340da8ca8fcc5aa58a7
6 files changed +21 -1
environment.c
+4
@@ -177,6 +177,10 @@ void setup_git_env(const char *git_dir)
177 args.graft_file = getenv_safe(&to_free, GRAFT_ENVIRONMENT);
178 args.index_file = getenv_safe(&to_free, INDEX_ENVIRONMENT);
179 args.alternate_db = getenv_safe(&to_free, ALTERNATE_DB_ENVIRONMENT);
180 + if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
181 + args.disable_ref_updates = 1;
182 + }
183 +
184 repo_set_gitdir(the_repository, git_dir, &args);
185 strvec_clear(&to_free);
186
object-file.c
+6
@@ -767,6 +767,12 @@ struct object_directory *set_temporary_primary_odb(const char *dir, int will_des
767 */
768 new_odb = xcalloc(1, sizeof(*new_odb));
769 new_odb->path = xstrdup(dir);
770 +
771 + /*
772 + * Disable ref updates while a temporary odb is active, since
773 + * the objects in the database may roll back.
774 + */
775 + new_odb->disable_ref_updates = 1;
776 new_odb->will_destroy = will_destroy;
777 new_odb->next = the_repository->objects->odb;
778 the_repository->objects->odb = new_odb;
object-store.h
+7
@@ -27,6 +27,13 @@ struct object_directory {
27 uint32_t loose_objects_subdir_seen[8]; /* 256 bits */
28 struct oidtree *loose_objects_cache;
29
30 + /*
31 + * This is a temporary object store created by the tmp_objdir
32 + * facility. Disable ref updates since the objects in the store
33 + * might be discarded on rollback.
34 + */
35 + int disable_ref_updates;
36 +
37 /*
38 * This object store is ephemeral, so there is no need to fsync.
39 */
refs.c
+1 -1
@@ -2126,7 +2126,7 @@ int ref_transaction_prepare(struct ref_transaction *transaction,
2126 break;
2127 }
2128
2129 - if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
2129 + if (refs->repo->objects->odb->disable_ref_updates) {
2130 strbuf_addstr(err,
2131 _("ref updates forbidden inside quarantine environment"));
2132 return -1;
repository.c
+2
@@ -80,6 +80,8 @@ void repo_set_gitdir(struct repository *repo,
80 expand_base_dir(&repo->objects->odb->path, o->object_dir,
81 repo->commondir, "objects");
82
83 + repo->objects->odb->disable_ref_updates = o->disable_ref_updates;
84 +
85 free(repo->objects->alternate_db);
86 repo->objects->alternate_db = xstrdup_or_null(o->alternate_db);
87 expand_base_dir(&repo->graft_file, o->graft_file,
repository.h
+1
@@ -162,6 +162,7 @@ struct set_gitdir_args {
162 const char *graft_file;
163 const char *index_file;
164 const char *alternate_db;
165 + int disable_ref_updates;
166 };
167
168 void repo_set_gitdir(struct repository *repo, const char *root,