[PATCH v2 06/13] builtin/grep: stop registering submodule ODB as source
From: Patrick Steinhardt <hidden>
Date: 2026-09-02 13:35:15
Subsystem:
the rest · Maintainer:
Linus Torvalds
Same as with the preceding commit, git-grep(1) registers each submodule's object database as an in-memory source of the main object database before grepping it. This was introduced as an eager alternate registration and converted into the lazy mechanism via 8d33c3af0b (grep: use submodule-ODB-as-alternate lazy-addition, 2021-08-16). Starting with 0693806bf8 (grep: add repository to OID grep sources, 2021-08-16), the command instead knows to pass submodule repositories to our workers, which means that those now use that repository to look up objects, too. As a consequence, registering submodule sources as alternates is not required anymore. Remove the logic to register submodule sources. Unfortunately, this does not allow us to get rid of the object read lock as initializing the subrepository is still racy. Signed-off-by: Patrick Steinhardt <redacted> --- builtin/grep.c | 26 ++++++-------------------- 1 file changed, 6 insertions(+), 20 deletions(-)
diff --git a/builtin/grep.c b/builtin/grep.c
index 073dfaaf45..b045f8a488 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c@@ -463,16 +463,6 @@ static int grep_submodule(struct grep_opt *opt, ALLOC_GROW(repos_to_free, repos_to_free_nr + 1, repos_to_free_alloc); repos_to_free[repos_to_free_nr++] = subrepo; - /* - * NEEDSWORK: repo_read_gitmodules() might call - * odb_add_to_alternates_memory() via config_from_gitmodules(). This - * operation causes a race condition with concurrent object readings - * performed by the worker threads. That's why we need obj_read_lock() - * here. It should be removed once it's no longer necessary to add the - * subrepo's odbs to the in-memory alternates list. - */ - obj_read_lock(); - /* * NEEDSWORK: when reading a submodule, the sparsity settings in the * superproject are incorrectly forgotten or misused. For example:
@@ -498,18 +488,14 @@ static int grep_submodule(struct grep_opt *opt, * ditto. * * Note that this list is not exhaustive. + * + * NEEDSWORK: initializing the subrepository is not thread-safe, + * either, as it may cause us to race around `get_main_ref_store()`. We + * thus need to hold the object-read lock to serialize all readers with + * one another. */ + obj_read_lock(); repo_read_gitmodules(subrepo, 0); - - /* - * All code paths tested by test code no longer need submodule ODBs to - * be added as alternates, but add it to the list just in case. - * Submodule ODBs added through add_submodule_odb_by_path() will be - * lazily registered as alternates when needed (and except in an - * unexpected code interaction, it won't be needed). - */ - odb_add_submodule_source_by_path(the_repository->objects, - subrepo->objects->sources->path); obj_read_unlock(); memcpy(&subopt, opt, sizeof(subopt));
--
2.55.0.979.g7e5102b832.dirty