From: Patrick Steinhardt Date: Fri, 06 Feb 2026 14:33:39 GMT Subject: Re: [PATCH v4 3/4] refs: parse and use the reference storage payload Message-ID: In-Reply-To: <20260202-kn-alternate-ref-dir-v4-3-3b30430411e3@gmail.com> On Mon, Feb 02, 2026 at 01:26:32PM +0100, Karthik Nayak wrote: > The previous commit extended the 'extensions.refStorage' config to add > support for a reference storage payload. The payload provides backend > specific information on where to store references for a given directory. > > Propagate this information to individual backends when initializing them > via the 'init()' function. Both the files and reftable backends will > parse the information to be filesystem paths to store references. > > To enable this, provide a 'refs_compute_filesystem_location()' function > which will parse the current 'gitdir' and the 'payload' to provide the > final reference directory and common reference directory (if working in > a linked worktree). > > Finally, for linked worktrees, traditionally references were stored in > the '$GIT_DIR/worktrees/' path. But when using an alternate > reference storage path, it doesn't make sense to store main worktree > references in the new path, and linked worktree references in the > $GIT_DIR path. So, let's store linked worktree references in > '$ALTERNATE_REFERENCE_DIR/worktrees// > diff --git a/Documentation/config/extensions.adoc b/Documentation/config/extensions.adoc > index 532456644b..df86da6aa7 100644 > --- a/Documentation/config/extensions.adoc > +++ b/Documentation/config/extensions.adoc > @@ -57,10 +57,24 @@ For historical reasons, this extension is respected regardless of the > `core.repositoryFormatVersion` setting. > > refStorage::: > - Specify the ref storage format to use. The acceptable values are: > + Specify the ref storage format and location to use. The value can be > + either a format name or a URI: > + > -- > +* A format name alone (e.g., `reftable` or `files`) uses the default > + location (the repository's common directory). > + > +* A URI format `://` explicitly specifies both the I think I mentioned this before, but shouldn't we say payload instead of location here? It may not be a location for all backends. > diff --git a/builtin/worktree.c b/builtin/worktree.c > index fbdaf2eb2e..800a376ac5 100644 > --- a/builtin/worktree.c > +++ b/builtin/worktree.c > @@ -425,6 +425,40 @@ static int make_worktree_orphan(const char * ref, const struct add_opts *opts, > return run_command(&cp); > } > > +/* > + * References for worktress are generally stored in '$GIT_DIR/worktrees/'. > + * But when using alternate reference directories, we want to store the worktree > + * references in '$ALTERNATE_REFERENCE_DIR/worktrees/'. > + * > + * Create the necessary folder structure to facilitate the same. But to ensure > + * that the former path is still considered a Git directory, add stubs (similar > + * to how we do in the reftable backend). > + */ I think the last part in the braces isn't necessary to say anymore given that we simply shell out to a function now. > diff --git a/refs.c b/refs.c > index 32b4edaf2d..c1d69082a9 100644 > --- a/refs.c > +++ b/refs.c > @@ -2224,7 +2225,11 @@ static struct ref_store *ref_store_init(struct repository *repo, > if (!be) > BUG("reference backend is unknown"); > > - refs = be->init(repo, gitdir, flags); > + /* > + * TODO Send in a 'struct worktree' instead of a 'gitdir', and > + * allow the backend to handle how it wants to deal with worktrees. > + */ It would be nice if the commit message mentioned why this isn't done now already. > diff --git a/refs/files-backend.c b/refs/files-backend.c > index 240d3c3b26..160ecb53b7 100644 > --- a/refs/files-backend.c > +++ b/refs/files-backend.c > @@ -106,19 +106,24 @@ static void clear_loose_ref_cache(struct files_ref_store *refs) > * set of caches. > */ > static struct ref_store *files_ref_store_init(struct repository *repo, > + const char *payload, > const char *gitdir, > unsigned int flags) > { > struct files_ref_store *refs = xcalloc(1, sizeof(*refs)); > struct ref_store *ref_store = (struct ref_store *)refs; > - struct strbuf sb = STRBUF_INIT; > + struct strbuf ref_common_dir = STRBUF_INIT; > + struct strbuf refdir = STRBUF_INIT; > + bool is_worktree; > + > + refs_compute_filesystem_location(gitdir, payload, &is_worktree, &refdir, > + &ref_common_dir); > > - base_ref_store_init(ref_store, repo, gitdir, &refs_be_files); > + base_ref_store_init(ref_store, repo, refdir.buf, &refs_be_files); > refs->store_flags = flags; > - get_common_dir_noenv(&sb, gitdir); > - refs->gitcommondir = strbuf_detach(&sb, NULL); > + refs->gitcommondir = xstrdup(ref_common_dir.buf); We can use `strbuf_detach()` instead to save an allocation and then use `refs->gitcommondir` below. > refs->packed_ref_store = > - packed_ref_store_init(repo, refs->gitcommondir, flags); > + packed_ref_store_init(repo, payload, ref_common_dir.buf, flags); > refs->log_all_ref_updates = repo_settings_get_log_all_ref_updates(repo); > repo_config_get_bool(repo, "core.prefersymlinkrefs", &refs->prefer_symlink_refs); Patrick