core: Add composefs digest for local commits too

This pairs with dbe7821
where we generate composefs metadata for base images.

It's going to be useful to do it for client side builds too, so
that we can treat them symmetrically.  It doesn't have
a very high cost, just a metadata traversal.

src/libpriv/rpmostree-core.cxx

@@ -4718,9 +4718,12 @@ rpmostree_context_commit (RpmOstreeContext *self, const char *parent,
         if (!ostree_commit_metadata_for_bootable (root, metadata_dict, cancellable, error))
           return FALSE;
       }
-    g_autoptr (GVariant) metadata = g_variant_dict_end (metadata_dict);
+    if (!ostree_repo_commit_add_composefs_metadata (self->ostreerepo, 0, metadata_dict,
+                                                    (OstreeRepoFile *)root, cancellable, error))
+      return glnx_prefix_error (error, "Adding composefs metadata");
 
     {
+      g_autoptr (GVariant) metadata = g_variant_dict_end (metadata_dict);
       if (!ostree_repo_write_commit (self->ostreerepo, parent, "", "", metadata,
                                      OSTREE_REPO_FILE (root), &ret_commit_checksum, cancellable,
                                      error))

src/libpriv/rpmostree-postprocess.cxx

@@ -838,17 +838,9 @@ rpmostree_compose_commit (int rootfs_fd, OstreeRepo *repo, const char *parent_re
   // Unfortunately these API takes GVariantDict, not GVariantBuilder, so convert
   g_autoptr (GVariantDict) metadata_dict = g_variant_dict_new (src_metadata);
 
-#if OSTREE_CHECK_VERSION(2023, 4)
-  g_autoptr (GError) local_error = NULL;
-  if (!ostree_repo_commit_add_composefs_metadata (
-          repo, 0, metadata_dict, (OstreeRepoFile *)root_tree, cancellable, &local_error)
-      && !g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED))
-    {
-      g_propagate_prefixed_error (error, util::move_nullify (local_error),
-                                  "Adding composefs metadata");
-      return FALSE;
-    }
-#endif
+  if (!ostree_repo_commit_add_composefs_metadata (repo, 0, metadata_dict,
+                                                  (OstreeRepoFile *)root_tree, cancellable, error))
+    return glnx_prefix_error (error, "Adding composefs metadata");
 
   if (!container)
     {

tests/kolainst/destructive/layering-local

@@ -76,6 +76,9 @@ fi
 ostree show --print-metadata-key=ostree.bootable ${booted_commit} >out.txt
 assert_file_has_content_literal out.txt 'true'
 echo "ok bootable metadata"
+ostree show --print-metadata-key=ostree.composefs.digest.v0 ${booted_commit} >out.txt
+assert_file_has_content_literal out.txt 'byte'
+echo "ok composefs metadata on client generated commit"
 
 # check we could uninstall the package using either its NEVRA or name
 rpm-ostree uninstall foo-1.2-3.x86_64