Re: [PATCH v2 05/13] submodule-config: stop registering submodule sources
From: Justin Tobler <hidden>
Date: 2026-09-06 18:38:20
On 26/09/02 03:34PM, Patrick Steinhardt wrote:
When reading the ".gitmodules" file from a blob in a repository other than `the_repository`, we register the repository's object database as an in-memory source of `the_repository`'s object database. This call has its origins in d9b8b8f896 (submodule-config.c: use repo_get_oid for reading .gitmodules, 2019-04-16): back then, `config_with_options()` was not able to read a blob from an arbitrary repository, but would always read it via `the_repository`. So even though the blob could be resolved in the submodule repository via `repo_get_oid()`, the submodule's object database had to be registered as an in-memory source of `the_repository` so that the subsequent object read was able to find the blob at all.
Ok, so IIUC the problem was that a gitmodule blob from a repository that is not "the_repository" would fail to be read by `config_with_options()` because it would only read objects from "the_repository". The workaround was to add the other repositories as another source to ensure the gitmodule blob could be read. I had to reread the commit message a couple of times to follow, but I think it makes sense now.
That need went away with e3e8bf046e (submodule-config: pass repo upon blob config read, 2021-08-16), which taught the config machinery to read the blob from the repository we pass to it. The same series converted the eager submodule source registration into a lazy mechanism that only registers submodule sources with the object database when an object lookup failed. The intent though was that we don't ever have to fall back to this mechanism in the first place, and to verify that this is the case we introduced GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB. If set, then any such lazy registration would cause us to BUG. At the beginning of this series, we still triggered this bug in t1092. But now that we have converted the "cache-tree" subsystem to not depend on `the_repository` anymore it also knows to properly access objects via the submodule. With that change, GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB does not cause any failures anymore.
Ok, now we can properly read objects from their respective repository source and no longer neeed the workaround.
quoted hunk ↗ jump to hunk
Remove the call to `odb_add_submodule_source_by_path()`. This removes the last user of `the_repository`, so at the same time we can also get rid of `USE_THE_REPOSITORY_VARIABLE`. Signed-off-by: Patrick Steinhardt <redacted> --- submodule-config.c | 4 ---- 1 file changed, 4 deletions(-)diff --git a/submodule-config.c b/submodule-config.c index 7c73fa108b..37c3be377b 100644 --- a/submodule-config.c +++ b/submodule-config.c@@ -1,4 +1,3 @@ -#define USE_THE_REPOSITORY_VARIABLE #define DISABLE_SIGN_COMPARE_WARNINGS #include "git-compat-util.h"@@ -803,9 +802,6 @@ static void config_from_gitmodules(config_fn_t fn, struct repository *repo, void } else if (repo_get_oid(repo, GITMODULES_INDEX, &oid) >= 0 || repo_get_oid(repo, GITMODULES_HEAD, &oid) >= 0) { config_source.blob = oidstr = xstrdup(oid_to_hex(&oid)); - if (repo != the_repository) - odb_add_submodule_source_by_path(the_repository->objects, - repo->objects->sources->path);
Nice to have one less workaround. :) -Justin