[PATCH 10/13] odb: handle initialization of sources in `odb_new()`

From: Patrick Steinhardt <ps@pks.im>
Date: Nov 19, 2025, 07:50 UTC
Message-ID: <20251119-b4-pks-odb-creation-v1-10-2b2ed2612cb6@pks.im>
In-Reply-To: <20251119-b4-pks-odb-creation-v1-0-2b2ed2612cb6@pks.im>

The logic to set up a new object database is currently distributed across two functions in "repository.c":

  - In `initialize_repository()` we initialize an empty object database.
    This object database is not fully initialized and doesn't have any
    sources attached to it.

  - The primary object database source is then created in
    `repo_set_gitdir()`.

Ideally though, the logic should be entirely self-contained so that we can iterate more readily on how exactly the sources themselves get set up.

Refactor `odb_new()` to handle both allocation and setup of the object database. This ensures that the object database is always initialized and ready for use, and it allows us to change how the sources get set up eventually.

Note that `repo_set_gitdir()` still reaches into the sources when the function gets called with an already-initialized object database. This will be fixed in the next commit.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 odb.c        | 14 +++++++++++++-
 odb.h        | 15 ++++++++++++++-
 repository.c | 20 ++++++++------------
 3 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/odb.c b/odb.c
index ccc6e999e7..88b40c81c0 100644
--- a/odb.c
+++ b/odb.c
@@ -1034,15 +1034,27 @@ int odb_write_object_stream(struct object_database *odb,
 	return odb_source_loose_write_stream(odb->sources, stream, len, oid);
 }
 
-struct object_database *odb_new(struct repository *repo)
+struct object_database *odb_new(struct repository *repo,
+				const char *primary_source,
+				const char *secondary_sources)
 {
 	struct object_database *o = xmalloc(sizeof(*o));
+	char *to_free = NULL;
 
 	memset(o, 0, sizeof(*o));
 	o->repo = repo;
 	o->packfiles = packfile_store_new(o);
 	pthread_mutex_init(&o->replace_mutex, NULL);
 	string_list_init_dup(&o->submodule_source_paths);
+
+	if (!primary_source)
+		primary_source = to_free = xstrfmt("%s/objects", repo->commondir);
+	o->sources = odb_source_new(o, primary_source, true);
+	o->sources_tail = &o->sources->next;
+	o->alternate_db = xstrdup_or_null(secondary_sources);
+
+	free(to_free);
+
 	return o;
 }
 
diff --git a/odb.h b/odb.h
index 99c4d48972..41b3c03027 100644
--- a/odb.h
+++ b/odb.h
@@ -159,7 +159,20 @@ struct object_database {
 	struct string_list submodule_source_paths;
 };
 
-struct object_database *odb_new(struct repository *repo);
+/*
+ * Create a new object database for the given repository.
+ *
+ * If the primary source parameter is set it will override the usual primary
+ * object directory derived from the repository's common directory. The
+ * alternate sources are expected to be a PATH_SEP-separated list of secondary
+ * sources. Note that these alternate sources will be added in addition to, not
+ * instead of, the alternates identified by the primary source.
+ *
+ * Returns the newly created object database.
+ */
+struct object_database *odb_new(struct repository *repo,
+				const char *primary_source,
+				const char *alternate_sources);
 
 /* Free the object database and release all resources. */
 void odb_free(struct object_database *o);
diff --git a/repository.c b/repository.c
index 455c2d279f..5975c8f341 100644
--- a/repository.c
+++ b/repository.c
@@ -52,7 +52,6 @@ static void set_default_hash_algo(struct repository *repo)
 
 void initialize_repository(struct repository *repo)
 {
-	repo->objects = odb_new(repo);
 	repo->remote_state = remote_state_new();
 	repo->parsed_objects = parsed_object_pool_new(repo);
 	ALLOC_ARRAY(repo->index, 1);
@@ -160,29 +159,26 @@ void repo_set_gitdir(struct repository *repo,
 	 * until after xstrdup(root). Then we can free it.
 	 */
 	char *old_gitdir = repo->gitdir;
-	char *objects_path = NULL;
 
 	repo->gitdir = xstrdup(gitfile ? gitfile : root);
 	free(old_gitdir);
 
 	repo_set_commondir(repo, o->commondir);
-	expand_base_dir(&objects_path, o->object_dir,
-			repo->commondir, "objects");
-
-	if (!repo->objects->sources) {
-		repo->objects->sources = odb_source_new(repo->objects,
-							objects_path, true);
-		repo->objects->sources_tail = &repo->objects->sources->next;
-		free(objects_path);
+
+	if (!repo->objects) {
+		repo->objects = odb_new(repo, o->object_dir, o->alternate_db);
 	} else {
+		char *objects_path = NULL;
+		expand_base_dir(&objects_path, o->object_dir,
+				repo->commondir, "objects");
 		free(repo->objects->sources->path);
 		repo->objects->sources->path = objects_path;
+		free(repo->objects->alternate_db);
+		repo->objects->alternate_db = xstrdup_or_null(o->alternate_db);
 	}
 
 	repo->disable_ref_updates = o->disable_ref_updates;
 
-	free(repo->objects->alternate_db);
-	repo->objects->alternate_db = xstrdup_or_null(o->alternate_db);
 	expand_base_dir(&repo->graft_file, o->graft_file,
 			repo->commondir, "info/grafts");
 	expand_base_dir(&repo->index_file, o->index_file,

-- 
2.52.0.rc2.482.gaa765fefd0.dirty