git · johnrichardrinehart · Aug 9, 2026 · Aug 9, 2026
diff --git a/Documentation/gitnamespaces.adoc b/Documentation/gitnamespaces.adoc
@@ -8,6 +8,7 @@ gitnamespaces - Git namespaces
 SYNOPSIS
 --------
 [verse]
+GIT_NAMESPACE=<namespace> git <command>
 GIT_NAMESPACE=<namespace> 'git upload-pack'
 GIT_NAMESPACE=<namespace> 'git receive-pack'
 
@@ -45,11 +46,19 @@ also avoids ambiguity with strange namespace paths such as `foo/refs/heads/`,
 which could otherwise generate directory/file conflicts within the `refs`
 directory.
 
+For ordinary Git commands, `GIT_NAMESPACE` selects the local ref view.
+A ref such as `refs/heads/main` resolves to the corresponding ref inside
+the selected namespace.  Branch, tag, tracking, fetch, and push commands
+use these logical ref names.
+
 linkgit:git-upload-pack[1] and linkgit:git-receive-pack[1] rewrite the
 names of refs as specified by `GIT_NAMESPACE`.  git-upload-pack and
 git-receive-pack will ignore all references outside the specified
 namespace.
 
+Reference maintenance commands such as linkgit:git-gc[1] protect refs from
+all namespaces because every namespace shares the object store.
+
 The smart HTTP server, linkgit:git-http-backend[1], will pass
 GIT_NAMESPACE through to the backend programs; see
 linkgit:git-http-backend[1] for sample configuration to expose

diff --git a/builtin/gc.c b/builtin/gc.c
@@ -863,7 +863,7 @@ static int should_write_commit_graph(struct gc_config *cfg UNUSED)
 	if (data.limit < 0)
 		return 1;
 
-	result = refs_for_each_ref(get_main_ref_store(the_repository),
+	result = refs_for_each_ref_all(get_main_ref_store(the_repository),
 				   dfs_on_ref, &data);
 
 	repo_clear_commit_marks(the_repository, SEEN);

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
@@ -5324,6 +5324,8 @@ int cmd_pack_objects(int argc,
 		strvec_push(&rp, "--objects");
 
 	if (rev_list_all) {
+		/* --all must protect every namespace in the shared object store. */
+		set_git_namespace_is_local(0);
 		use_internal_rev_list = 1;
 		strvec_push(&rp, "--all");
 	}

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
@@ -2632,6 +2632,7 @@ int cmd_receive_pack(int argc,
 		OPT_END()
 	};
 
+	set_git_namespace_is_local(0);
 	packet_trace_identity("receive-pack");
 
 	argc = parse_options(argc, argv, prefix, options, receive_pack_usage, 0);

diff --git a/builtin/upload-pack.c b/builtin/upload-pack.c
@@ -43,6 +43,7 @@ int cmd_upload_pack(int argc,
 	};
 	unsigned enter_repo_flags = ENTER_REPO_ANY_OWNER_OK;
 
+	set_git_namespace_is_local(0);
 	packet_trace_identity("upload-pack");
 	disable_replace_refs();
 	save_commit_buffer = 0;

diff --git a/environment.c b/environment.c
@@ -168,6 +168,18 @@ int have_git_dir(void)
 		|| the_repository->gitdir;
 }
 
+static int git_namespace_local = 1;
+
+int git_namespace_is_local(void)
+{
+	return git_namespace_local;
+}
+
+void set_git_namespace_is_local(int is_local)
+{
+	git_namespace_local = is_local;
+}
+
 const char *get_git_namespace(void)
 {
 	static const char *namespace;

diff --git a/environment.h b/environment.h
@@ -168,6 +168,8 @@ int use_optional_locks(void);
 
 const char *get_git_namespace(void);
 const char *strip_namespace(const char *namespaced_ref);
+int git_namespace_is_local(void);
+void set_git_namespace_is_local(int is_local);
 
 int git_default_config(const char *, const char *,
 		       const struct config_context *, void *);

diff --git a/http-backend.c b/http-backend.c
@@ -771,6 +771,7 @@ int cmd_main(int argc UNUSED, const char **argv UNUSED)
 	int i;
 	struct strbuf hdr = STRBUF_INIT;
 
+	set_git_namespace_is_local(0);
 	set_die_routine(die_webcgi);
 	set_die_is_recursing_routine(die_webcgi_recursing);
 

diff --git a/reachable.c b/reachable.c
@@ -317,7 +317,7 @@ void mark_reachable_objects(struct rev_info *revs, int mark_reflog,
 	add_index_objects_to_pending(revs, 0);
 
 	/* Add all external refs */
-	refs_for_each_ref(get_main_ref_store(the_repository), add_one_ref,
+	refs_for_each_ref_all(get_main_ref_store(the_repository), add_one_ref,
 			  revs);
 
 	/* detached HEAD is not included in the list above */