Merge branch 'kn/ref-location'

Allow the directory in which reference backends store their data to
be specified.

* kn/ref-location:
  refs: add GIT_REFERENCE_BACKEND to specify reference backend
  refs: allow reference location in refstorage config
  refs: receive and use the reference storage payload
  refs: move out stub modification to generic layer
  refs: extract out `refs_create_refdir_stubs()`
  setup: don't modify repo in `create_reference_database()`

5 files changed, 51 insertions, 53 deletions

diff --git a/refs/files-backend.c b/refs/files-backend.c
index b1b13b41f6..d2c4be1653 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 = strbuf_detach(&ref_common_dir, NULL);
 	refs->packed_ref_store =
-		packed_ref_store_init(repo, refs->gitcommondir, flags);
+		packed_ref_store_init(repo, NULL, refs->gitcommondir, 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);
 
@@ -126,6 +131,8 @@ static struct ref_store *files_ref_store_init(struct repository *repo,
 	chdir_notify_reparent("files-backend $GIT_COMMONDIR",
 			      &refs->gitcommondir);
 
+	strbuf_release(&refdir);
+
 	return ref_store;
 }
 
@@ -3699,7 +3706,11 @@ static int files_ref_store_remove_on_disk(struct ref_store *ref_store,
 	if (for_each_root_ref(refs, remove_one_root_ref, &data) < 0)
 		ret = -1;
 
-	if (ref_store_remove_on_disk(refs->packed_ref_store, err) < 0)
+	/*
+	 * Directly access the cleanup functions for packed-refs as the generic function
+	 * would try to clear stubs which isn't required for the files backend.
+	 */
+	if (refs->packed_ref_store->be->remove_on_disk(refs->packed_ref_store, err) < 0)
 		ret = -1;
 
 	strbuf_release(&sb);
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 59b3ecb9d6..8872a7fe18 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -211,7 +211,12 @@ static size_t snapshot_hexsz(const struct snapshot *snapshot)
 	return snapshot->refs->base.repo->hash_algo->hexsz;
 }
 
+/*
+ * Since packed-refs is only stored in the common dir, don't parse the
+ * payload and rely on the files-backend to set 'gitdir' correctly.
+ */
 struct ref_store *packed_ref_store_init(struct repository *repo,
+					const char *payload UNUSED,
 					const char *gitdir,
 					unsigned int store_flags)
 {
diff --git a/refs/packed-backend.h b/refs/packed-backend.h
index 9481d5e7c2..2c2377a356 100644
--- a/refs/packed-backend.h
+++ b/refs/packed-backend.h
@@ -14,6 +14,7 @@ struct ref_transaction;
  */
 
 struct ref_store *packed_ref_store_init(struct repository *repo,
+					const char *payload,
 					const char *gitdir,
 					unsigned int store_flags);
 
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 191a25683f..d79e35fd26 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -391,6 +391,7 @@ struct ref_store;
  * the ref_store and to record the ref_store for later lookup.
  */
 typedef struct ref_store *ref_store_init_fn(struct repository *repo,
+					    const char *payload,
 					    const char *gitdir,
 					    unsigned int flags);
 /*
@@ -668,4 +669,17 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 					  unsigned int initial_transaction,
 					  struct strbuf *err);
 
+/*
+ * Given a gitdir and the reference storage payload provided, retrieve the
+ * 'refdir' and 'ref_common_dir'. The former is where references should be
+ * stored for the current worktree, the latter is the common reference
+ * directory if working with a linked worktree. If working with the main
+ * worktree, both values will be the same.
+ *
+ * This is used by backends that store references in the repository directly.
+ */
+void refs_compute_filesystem_location(const char *gitdir, const char *payload,
+				      bool *is_worktree, struct strbuf *refdir,
+				      struct strbuf *ref_common_dir);
+
 #endif /* REFS_REFS_INTERNAL_H */
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 5611808ad7..57b5d48905 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -372,18 +372,24 @@ static int reftable_be_fsync(int fd)
 }
 
 static struct ref_store *reftable_be_init(struct repository *repo,
+					  const char *payload,
 					  const char *gitdir,
 					  unsigned int store_flags)
 {
 	struct reftable_ref_store *refs = xcalloc(1, sizeof(*refs));
+	struct strbuf ref_common_dir = STRBUF_INIT;
+	struct strbuf refdir = STRBUF_INIT;
 	struct strbuf path = STRBUF_INIT;
-	int is_worktree;
+	bool is_worktree;
 	mode_t mask;
 
 	mask = umask(0);
 	umask(mask);
 
-	base_ref_store_init(&refs->base, repo, gitdir, &refs_be_reftable);
+	refs_compute_filesystem_location(gitdir, payload, &is_worktree, &refdir,
+					 &ref_common_dir);
+
+	base_ref_store_init(&refs->base, repo, refdir.buf, &refs_be_reftable);
 	strmap_init(&refs->worktree_backends);
 	refs->store_flags = store_flags;
 	refs->log_all_ref_updates = repo_settings_get_log_all_ref_updates(repo);
@@ -419,14 +425,11 @@ static struct ref_store *reftable_be_init(struct repository *repo,
 	/*
 	 * Set up the main reftable stack that is hosted in GIT_COMMON_DIR.
 	 * This stack contains both the shared and the main worktree refs.
-	 *
-	 * Note that we don't try to resolve the path in case we have a
-	 * worktree because `get_common_dir_noenv()` already does it for us.
 	 */
-	is_worktree = get_common_dir_noenv(&path, gitdir);
+	strbuf_addbuf(&path, &ref_common_dir);
 	if (!is_worktree) {
 		strbuf_reset(&path);
-		strbuf_realpath(&path, gitdir, 0);
+		strbuf_realpath(&path, ref_common_dir.buf, 0);
 	}
 	strbuf_addstr(&path, "/reftable");
 	refs->err = reftable_backend_init(&refs->main_backend, path.buf,
@@ -443,10 +446,9 @@ static struct ref_store *reftable_be_init(struct repository *repo,
 	 * do it efficiently.
 	 */
 	if (is_worktree) {
-		strbuf_reset(&path);
-		strbuf_addf(&path, "%s/reftable", gitdir);
+		strbuf_addstr(&refdir, "/reftable");
 
-		refs->err = reftable_backend_init(&refs->worktree_backend, path.buf,
+		refs->err = reftable_backend_init(&refs->worktree_backend, refdir.buf,
 						  &refs->write_options);
 		if (refs->err)
 			goto done;
@@ -456,6 +458,8 @@ static struct ref_store *reftable_be_init(struct repository *repo,
 
 done:
 	assert(refs->err != REFTABLE_API_ERROR);
+	strbuf_release(&ref_common_dir);
+	strbuf_release(&refdir);
 	strbuf_release(&path);
 	return &refs->base;
 }
@@ -491,19 +495,6 @@ static int reftable_be_create_on_disk(struct ref_store *ref_store,
 	safe_create_dir(the_repository, sb.buf, 1);
 	strbuf_reset(&sb);
 
-	strbuf_addf(&sb, "%s/HEAD", refs->base.gitdir);
-	write_file(sb.buf, "ref: refs/heads/.invalid");
-	adjust_shared_perm(the_repository, sb.buf);
-	strbuf_reset(&sb);
-
-	strbuf_addf(&sb, "%s/refs", refs->base.gitdir);
-	safe_create_dir(the_repository, sb.buf, 1);
-	strbuf_reset(&sb);
-
-	strbuf_addf(&sb, "%s/refs/heads", refs->base.gitdir);
-	write_file(sb.buf, "this repository uses the reftable format");
-	adjust_shared_perm(the_repository, sb.buf);
-
 	strbuf_release(&sb);
 	return 0;
 }
@@ -529,30 +520,6 @@ static int reftable_be_remove_on_disk(struct ref_store *ref_store,
 			    strerror(errno));
 		ret = -1;
 	}
-	strbuf_reset(&sb);
-
-	strbuf_addf(&sb, "%s/HEAD", refs->base.gitdir);
-	if (unlink(sb.buf) < 0) {
-		strbuf_addf(err, "could not delete stub HEAD: %s",
-			    strerror(errno));
-		ret = -1;
-	}
-	strbuf_reset(&sb);
-
-	strbuf_addf(&sb, "%s/refs/heads", refs->base.gitdir);
-	if (unlink(sb.buf) < 0) {
-		strbuf_addf(err, "could not delete stub heads: %s",
-			    strerror(errno));
-		ret = -1;
-	}
-	strbuf_reset(&sb);
-
-	strbuf_addf(&sb, "%s/refs", refs->base.gitdir);
-	if (rmdir(sb.buf) < 0) {
-		strbuf_addf(err, "could not delete refs directory: %s",
-			    strerror(errno));
-		ret = -1;
-	}
 
 	strbuf_release(&sb);
 	return ret;