summary: Implement a new, more efficient, summary format

This drops the deltas from the summary and uses the per-commit
metadata field to add the cache data to avoid the need for the separate
xa.cache and xa.sparse-cache indexes. This way we avoid repeating the
refs in multiple places.

Nothing uses this format yet, but we still pass make check if we enable
it.

5 files changed, 336 insertions, 179 deletions

diff --git a/app/flatpak-builtins-repo.c b/app/flatpak-builtins-repo.c
index 0360c9dd..6207b8f1 100644
--- a/app/flatpak-builtins-repo.c
+++ b/app/flatpak-builtins-repo.c
@@ -70,9 +70,8 @@ ostree_repo_mode_to_string (OstreeRepoMode mode,
 
 static void
 print_info (OstreeRepo *repo,
-            GVariant   *meta)
+            GVariant   *summary)
 {
-  g_autoptr(GVariant) cache = NULL;
   const char *title;
   const char *comment;
   const char *description;
@@ -87,11 +86,15 @@ print_info (OstreeRepo *repo,
   g_autoptr(GVariant) gpg_keys = NULL;
   OstreeRepoMode mode;
   const char *mode_string = "unknown";
+  g_autoptr(GVariant) meta = NULL;
+  g_autoptr(GVariant) refs = NULL;
 
   mode = ostree_repo_get_mode (repo);
   ostree_repo_mode_to_string (mode, &mode_string, NULL);
   g_print (_("Repo mode: %s\n"), mode_string);
 
+  meta = g_variant_get_child_value (summary, 1);
+
   if (g_variant_lookup (meta, "xa.title", "&s", &title))
     g_print (_("Title: %s\n"), title);
 
@@ -134,44 +137,50 @@ print_info (OstreeRepo *repo,
       g_print (_("GPG key hash: %s\n"), gpg_data_checksum);
     }
 
-  cache = g_variant_lookup_value (meta, "xa.cache", NULL);
-  if (cache)
-    {
-      g_autoptr(GVariant) refdata = NULL;
-
-      refdata = g_variant_get_variant (cache);
-      g_print (_("%zd branches\n"), g_variant_n_children (refdata));
-    }
+  refs = g_variant_get_child_value (summary, 0);
+  g_print (_("%zd branches\n"), g_variant_n_children (refs));
 }
 
 static void
-print_branches (GVariant *meta)
+print_branches (GVariant *summary)
 {
-  g_autoptr(GVariant) cache = NULL;
-  g_autoptr(GVariant) sparse_cache = NULL;
+  g_autoptr(GVariant) meta = NULL;
+  guint summary_version = 0;
+  FlatpakTablePrinter *printer;
+
+  meta = g_variant_get_child_value (summary, 1);
+
+  g_variant_lookup (meta, "xa.summary-version", "u", &summary_version);
 
-  g_variant_lookup (meta, "xa.sparse-cache", "@a{sa{sv}}", &sparse_cache);
-  cache = g_variant_lookup_value (meta, "xa.cache", NULL);
-  if (cache)
+  printer = flatpak_table_printer_new ();
+  flatpak_table_printer_set_column_title (printer, 0, _("Ref"));
+  flatpak_table_printer_set_column_title (printer, 1, _("Installed"));
+  flatpak_table_printer_set_column_title (printer, 2, _("Download"));
+  flatpak_table_printer_set_column_title (printer, 3, _("Options"));
+
+  if (summary_version == 1)
     {
-      g_autoptr(GVariant) refdata = NULL;
+      g_autoptr(GVariant) refs = g_variant_get_child_value (summary, 0);
       GVariantIter iter;
       const char *ref;
-      guint64 installed_size;
-      guint64 download_size;
-      const char *metadata;
-      FlatpakTablePrinter *printer;
-
-      printer = flatpak_table_printer_new ();
-      flatpak_table_printer_set_column_title (printer, 0, _("Ref"));
-      flatpak_table_printer_set_column_title (printer, 1, _("Installed"));
-      flatpak_table_printer_set_column_title (printer, 2, _("Download"));
-      flatpak_table_printer_set_column_title (printer, 3, _("Options"));
-
-      refdata = g_variant_get_variant (cache);
-      g_variant_iter_init (&iter, refdata);
-      while (g_variant_iter_next (&iter, "{&s(tt&s)}", &ref, &installed_size, &download_size, &metadata))
+      GVariant *refdata_iter = NULL;
+
+      g_variant_iter_init (&iter, refs);
+      while (g_variant_iter_next (&iter, "(&s@(taya{sv}))", &ref, &refdata_iter))
         {
+          g_autoptr(GVariant) refdata = refdata_iter;
+          g_autoptr(GVariant) ref_meta = g_variant_get_child_value (refdata, 2);
+          g_autoptr(GVariant) data = g_variant_lookup_value (ref_meta, "xa.data", NULL);
+          guint64 installed_size;
+          guint64 download_size;
+          const char *metadata;
+          const char *eol;
+
+          if (data == NULL)
+            continue;
+
+          g_variant_get (data, "(tt&s)", &installed_size, &download_size, &metadata);
+
           g_autofree char *installed = g_format_size (GUINT64_FROM_BE (installed_size));
           g_autofree char *download = g_format_size (GUINT64_FROM_BE (download_size));
 
@@ -181,49 +190,120 @@ print_branches (GVariant *meta)
 
           flatpak_table_printer_add_column (printer, ""); /* Options */
 
-          if (sparse_cache)
+          if (g_variant_lookup (ref_meta, FLATPAK_SPARSE_CACHE_KEY_ENDOFLINE, "&s", &eol))
+            flatpak_table_printer_append_with_comma_printf (printer, "eol=%s", eol);
+          if (g_variant_lookup (ref_meta, FLATPAK_SPARSE_CACHE_KEY_ENDOFLINE_REBASE, "&s", &eol))
+            flatpak_table_printer_append_with_comma_printf (printer, "eol-rebase=%s", eol);
+
+          flatpak_table_printer_finish_row (printer);
+        }
+    }
+  else
+    {
+      g_autoptr(GVariant) cache = NULL;
+      g_autoptr(GVariant) sparse_cache = NULL;
+
+      g_variant_lookup (meta, "xa.sparse-cache", "@a{sa{sv}}", &sparse_cache);
+      cache = g_variant_lookup_value (meta, "xa.cache", NULL);
+      if (cache)
+        {
+          g_autoptr(GVariant) refdata = NULL;
+          GVariantIter iter;
+          const char *ref;
+          guint64 installed_size;
+          guint64 download_size;
+          const char *metadata;
+
+          refdata = g_variant_get_variant (cache);
+          g_variant_iter_init (&iter, refdata);
+          while (g_variant_iter_next (&iter, "{&s(tt&s)}", &ref, &installed_size, &download_size, &metadata))
             {
-              g_autoptr(GVariant) sparse = NULL;
-              if (g_variant_lookup (sparse_cache, ref, "@a{sv}", &sparse))
+              g_autofree char *installed = g_format_size (GUINT64_FROM_BE (installed_size));
+              g_autofree char *download = g_format_size (GUINT64_FROM_BE (download_size));
+
+              flatpak_table_printer_add_column (printer, ref);
+              flatpak_table_printer_add_decimal_column (printer, installed);
+              flatpak_table_printer_add_decimal_column (printer, download);
+
+              flatpak_table_printer_add_column (printer, ""); /* Options */
+
+              if (sparse_cache)
                 {
-                  const char *eol;
-                  if (g_variant_lookup (sparse, FLATPAK_SPARSE_CACHE_KEY_ENDOFLINE, "&s", &eol))
-                    flatpak_table_printer_append_with_comma_printf (printer, "eol=%s", eol);
-                  if (g_variant_lookup (sparse, FLATPAK_SPARSE_CACHE_KEY_ENDOFLINE_REBASE, "&s", &eol))
-                    flatpak_table_printer_append_with_comma_printf (printer, "eol-rebase=%s", eol);
+                  g_autoptr(GVariant) sparse = NULL;
+                  if (g_variant_lookup (sparse_cache, ref, "@a{sv}", &sparse))
+                    {
+                      const char *eol;
+                      if (g_variant_lookup (sparse, FLATPAK_SPARSE_CACHE_KEY_ENDOFLINE, "&s", &eol))
+                        flatpak_table_printer_append_with_comma_printf (printer, "eol=%s", eol);
+                      if (g_variant_lookup (sparse, FLATPAK_SPARSE_CACHE_KEY_ENDOFLINE_REBASE, "&s", &eol))
+                        flatpak_table_printer_append_with_comma_printf (printer, "eol-rebase=%s", eol);
+                    }
                 }
+
+              flatpak_table_printer_finish_row (printer);
             }
 
-          flatpak_table_printer_finish_row (printer);
         }
-
-      flatpak_table_printer_print (printer);
-      flatpak_table_printer_free (printer);
     }
+
+  flatpak_table_printer_print (printer);
+  flatpak_table_printer_free (printer);
 }
 
 static void
-print_metadata (GVariant   *meta,
+print_metadata (GVariant   *summary,
                 const char *branch)
 {
-  g_autoptr(GVariant) cache = NULL;
+  g_autoptr(GVariant) meta = NULL;
+  guint summary_version = 0;
+  guint64 installed_size;
+  guint64 download_size;
+  const char *metadata;
+  GVariantIter iter;
+  const char *ref;
+
+  meta = g_variant_get_child_value (summary, 1);
 
-  cache = g_variant_lookup_value (meta, "xa.cache", NULL);
-  if (cache)
+  g_variant_lookup (meta, "xa.summary-version", "u", &summary_version);
+
+  if (summary_version == 1)
     {
-      g_autoptr(GVariant) refdata = NULL;
-      GVariantIter iter;
-      const char *ref;
-      guint64 installed_size;
-      guint64 download_size;
-      const char *metadata;
+      g_autoptr(GVariant) refs = g_variant_get_child_value (summary, 0);
+      GVariant *refdata_iter = NULL;
 
-      refdata = g_variant_get_variant (cache);
-      g_variant_iter_init (&iter, refdata);
-      while (g_variant_iter_next (&iter, "{&s(tt&s)}", &ref, &installed_size, &download_size, &metadata))
+      g_variant_iter_init (&iter, refs);
+      while (g_variant_iter_next (&iter, "(&s@(taya{sv}))", &ref, &refdata_iter))
         {
+          g_autoptr(GVariant) refdata = refdata_iter;
+          g_autoptr(GVariant) ref_meta = g_variant_get_child_value (refdata, 2);
+
           if (strcmp (branch, ref) == 0)
-            g_print ("%s\n", metadata);
+            {
+              g_autoptr(GVariant) data = g_variant_lookup_value (ref_meta, "xa.data", NULL);
+              if (data)
+                {
+                  g_variant_get (data, "(tt&s)", &installed_size, &download_size, &metadata);
+                  g_print ("%s\n", metadata);
+                  break;
+                }
+            }
+        }
+    }
+  else /* Version 0 */
+    {
+      g_autoptr(GVariant) cache = g_variant_lookup_value (meta, "xa.cache", NULL);
+      if (cache)
+        {
+          g_autoptr(GVariant) refdata = g_variant_get_variant (cache);
+          g_variant_iter_init (&iter, refdata);
+          while (g_variant_iter_next (&iter, "{&s(tt&s)}", &ref, &installed_size, &download_size, &metadata))
+            {
+              if (strcmp (branch, ref) == 0)
+                {
+                  g_print ("%s\n", metadata);
+                  break;
+                }
+            }
         }
     }
 }
@@ -419,10 +499,8 @@ flatpak_builtin_repo (int argc, char **argv,
 {
   g_autoptr(GOptionContext) context = NULL;
   g_autoptr(GFile) location = NULL;
-  g_autoptr(GVariant) meta = NULL;
   g_autoptr(OstreeRepo) repo = NULL;
-  const char *ostree_metadata_ref = NULL;
-  g_autofree char *ostree_metadata_checksum = NULL;
+  g_autoptr(GVariant) summary = NULL;
   const char *collection_id;
 
   context = g_option_context_new (_("LOCATION - Repository maintenance"));
@@ -441,38 +519,11 @@ flatpak_builtin_repo (int argc, char **argv,
 
   collection_id = ostree_repo_get_collection_id (repo);
 
-  /* Try loading the metadata from the ostree-metadata branch first. If that
-   * fails, fall back to the summary file. */
-  ostree_metadata_ref = OSTREE_REPO_METADATA_REF;
-  if (!flatpak_repo_resolve_rev (repo, collection_id, NULL, ostree_metadata_ref,
-                                 TRUE, &ostree_metadata_checksum, cancellable, error))
-    return FALSE;
-
-  if (ostree_metadata_checksum != NULL)
-    {
-      g_autoptr(GVariant) commit_v = NULL;
-
-      if (!ostree_repo_load_commit (repo, ostree_metadata_checksum, &commit_v, NULL, error))
-        {
-          g_prefix_error (error, "Error getting repository metadata from %s ref: ", ostree_metadata_ref);
-          return FALSE;
-        }
-
-      meta = g_variant_get_child_value (commit_v, 0);
-      g_debug ("Using repository metadata from the ostree-metadata branch");
-    }
-  else
+  summary = flatpak_repo_load_summary (repo, error);
+  if (summary == NULL)
     {
-      g_autoptr(GVariant) summary = NULL;
-
-      summary = flatpak_repo_load_summary (repo, error);
-      if (summary == NULL)
-        {
-          g_prefix_error (error, "Error getting repository metadata from summary file: ");
-          return FALSE;
-        }
-      meta = g_variant_get_child_value (summary, 1);
-      g_debug ("Using repository metadata from the summary file");
+      g_prefix_error (error, "Error getting repository metadata from summary file: ");
+      return FALSE;
     }
 
   if (!opt_info && !opt_branches && !opt_metadata_branch && !opt_commits_branch)
@@ -480,13 +531,13 @@ flatpak_builtin_repo (int argc, char **argv,
 
   /* Print out the metadata. */
   if (opt_info)
-    print_info (repo, meta);
+    print_info (repo, summary);
 
   if (opt_branches)
-    print_branches (meta);
+    print_branches (summary);
 
   if (opt_metadata_branch)
-    print_metadata (meta, opt_metadata_branch);
+    print_metadata (summary, opt_metadata_branch);
 
   if (opt_commits_branch)
     {
diff --git a/common/flatpak-dir-private.h b/common/flatpak-dir-private.h
index a4cdf14d..2e84db35 100644
--- a/common/flatpak-dir-private.h
+++ b/common/flatpak-dir-private.h
@@ -119,6 +119,7 @@ typedef struct
 {
   char     *remote_name;
   char     *collection_id;
+  guint     summary_version;
   GVariant *summary;
   GBytes   *summary_bytes;
   GBytes   *summary_sig_bytes;
diff --git a/common/flatpak-dir.c b/common/flatpak-dir.c
index 1e7aff4f..9135e340 100644
--- a/common/flatpak-dir.c
+++ b/common/flatpak-dir.c
@@ -604,53 +604,74 @@ flatpak_remote_state_get_cache_version (FlatpakRemoteState *self)
   return GUINT32_FROM_LE (var_metadata_lookup_uint32 (meta, "xa.cache-version", 0));
 }
 
-static gboolean
-flatpak_remote_state_get_cache (FlatpakRemoteState *self,
-                                VarCacheRef        *out,
-                                GError            **error)
+gboolean
+flatpak_remote_state_lookup_cache (FlatpakRemoteState *self,
+                                   const char         *ref,
+                                   guint64            *out_download_size,
+                                   guint64            *out_installed_size,
+                                   const char        **out_metadata,
+                                   GError            **error)
 {
+  VarCacheDataRef cache_data;
   VarMetadataRef meta;
-  VarVariantRef cache_vv;
-  VarVariantRef cache_v;
   VarSummaryRef summary;
+  guint32 summary_version;
 
   if (!flatpak_remote_state_ensure_summary (self, error))
     return FALSE;
 
   summary = var_summary_from_gvariant (self->summary);
   meta = var_summary_get_metadata (summary);
-  if (!var_metadata_lookup (meta, "xa.cache", NULL, &cache_vv))
+
+  summary_version = GUINT32_FROM_LE (var_metadata_lookup_uint32 (meta, "xa.summary-version", 0));
+
+  if (summary_version == 0)
     {
-      flatpak_fail_error (error, FLATPAK_ERROR_INVALID_DATA, _("No summary or Flatpak cache available for remote %s"),
-                          self->remote_name);
-      return FALSE;
-    }
+      VarCacheRef cache;
+      gsize pos;
+      VarVariantRef cache_vv;
+      VarVariantRef cache_v;
 
-  /* For stupid historical reasons the xa.cache is double-wrapped in a variant */
-  cache_v = var_variant_from_variant (cache_vv);
-  *out = var_cache_from_variant (cache_v);
-  return TRUE;
-}
+      if (!var_metadata_lookup (meta, "xa.cache", NULL, &cache_vv))
+        {
+          flatpak_fail_error (error, FLATPAK_ERROR_INVALID_DATA, _("No summary or Flatpak cache available for remote %s"),
+                              self->remote_name);
+          return FALSE;
+        }
 
-gboolean
-flatpak_remote_state_lookup_cache (FlatpakRemoteState *self,
-                                   const char         *ref,
-                                   guint64            *out_download_size,
-                                   guint64            *out_installed_size,
-                                   const char        **out_metadata,
-                                   GError            **error)
-{
-  VarCacheRef cache;
-  VarCacheDataRef cache_data;
-  gsize pos;
+      /* For stupid historical reasons the xa.cache is double-wrapped in a variant */
+      cache_v = var_variant_from_variant (cache_vv);
+      cache = var_cache_from_variant (cache_v);
 
-  if (!flatpak_remote_state_get_cache (self, &cache, error))
-    return FALSE;
+      if (!var_cache_lookup (cache, ref, &pos, &cache_data))
+        return flatpak_fail_error (error, FLATPAK_ERROR_REF_NOT_FOUND,
+                                   _("No entry for %s in remote '%s' summary flatpak cache "),
+                                   ref, self->remote_name);
+    }
+  else if (summary_version == 1)
+    {
+      VarRefMapRef ref_map = var_summary_get_ref_map (summary);
+      VarRefInfoRef info;
+      VarMetadataRef commit_metadata;
+      VarVariantRef cache_data_v;
 
-  if (!var_cache_lookup (cache, ref, &pos, &cache_data))
-    return flatpak_fail_error (error, FLATPAK_ERROR_REF_NOT_FOUND,
-                               _("No entry for %s in remote '%s' summary flatpak cache "),
-                               ref, self->remote_name);
+      if (!flatpak_var_ref_map_lookup_ref (ref_map, ref, &info))
+        return flatpak_fail_error (error, FLATPAK_ERROR_REF_NOT_FOUND,
+                                   _("No entry for %s in remote '%s' summary cache "),
+                                   ref, self->remote_name);
+
+      commit_metadata = var_ref_info_get_metadata (info);
+      if (!var_metadata_lookup (commit_metadata, "xa.data", NULL, &cache_data_v))
+        return flatpak_fail_error (error, FLATPAK_ERROR_INVALID_DATA, _("Missing xa.data in summary for remote %s"),
+                                   self->remote_name);
+      cache_data = var_cache_data_from_variant (cache_data_v);
+    }
+  else
+    {
+      flatpak_fail_error (error, FLATPAK_ERROR_INVALID_DATA, _("Unsupported summary version %d for remote %s"),
+                          summary_version, self->remote_name);
+      return FALSE;
+    }
 
   if (out_installed_size)
     *out_installed_size = var_cache_data_get_installed_size (cache_data);
@@ -1025,22 +1046,45 @@ flatpak_remote_state_lookup_sparse_cache (FlatpakRemoteState *self,
   VarSummaryRef summary;
   VarMetadataRef meta;
   VarVariantRef sparse_cache_v;
+  guint32 summary_version;
 
   if (!flatpak_remote_state_ensure_summary (self, error))
     return FALSE;
 
   summary = var_summary_from_gvariant (self->summary);
   meta = var_summary_get_metadata (summary);
-  if (var_metadata_lookup (meta, "xa.sparse-cache", NULL, &sparse_cache_v))
+
+  summary_version = GUINT32_FROM_LE (var_metadata_lookup_uint32 (meta, "xa.summary-version", 0));
+
+  if (summary_version == 0)
     {
-      VarSparseCacheRef sparse_cache = var_sparse_cache_from_variant (sparse_cache_v);
-      return var_sparse_cache_lookup (sparse_cache, ref, NULL, out_metadata);
+      if (var_metadata_lookup (meta, "xa.sparse-cache", NULL, &sparse_cache_v))
+        {
+          VarSparseCacheRef sparse_cache = var_sparse_cache_from_variant (sparse_cache_v);
+          if (var_sparse_cache_lookup (sparse_cache, ref, NULL, out_metadata))
+            return TRUE;
+        }
     }
+  else if (summary_version == 1)
+    {
+      VarRefMapRef ref_map = var_summary_get_ref_map (summary);
+      VarRefInfoRef info;
 
-  g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND,
-               _("No entry for %s in remote summary flatpak sparse cache "), ref);
+      if (flatpak_var_ref_map_lookup_ref (ref_map, ref, &info))
+        {
+          *out_metadata = var_ref_info_get_metadata (info);
+          return TRUE;
+        }
+    }
+  else
+    {
+      flatpak_fail_error (error, FLATPAK_ERROR_INVALID_DATA, _("Unsupported summary version %d for remote %s"),
+                          summary_version, self->remote_name);
+      return FALSE;
+    }
 
-  return FALSE;
+  return flatpak_fail_error (error, FLATPAK_ERROR_REF_NOT_FOUND,
+                             _("No entry for %s in remote summary flatpak sparse cache "), ref);
 }
 
 static DirExtraData *
diff --git a/common/flatpak-utils-private.h b/common/flatpak-utils-private.h
index 7f55a0fa..c280419d 100644
--- a/common/flatpak-utils-private.h
+++ b/common/flatpak-utils-private.h
@@ -57,6 +57,11 @@
 #define FLATPAK_XA_CACHE_VERSION 1
 /* version 1 added extra data download size */
 
+#define FLATPAK_XA_SUMMARY_VERSION 1
+/* version 0/missing is standard ostree summary,
+ * version 1 is compact format with inline cache and no deltas
+ */
+
 gboolean flatpak_set_tty_echo (gboolean echo);
 void flatpak_get_window_size (int *rows,
                               int *cols);
@@ -170,6 +175,9 @@ gboolean flatpak_summary_lookup_ref (GVariant      *summary,
 gboolean flatpak_summary_find_ref_map (VarSummaryRef  summary,
                                        const char    *collection_id,
                                        VarRefMapRef  *refs_out);
+gboolean flatpak_var_ref_map_lookup_ref (VarRefMapRef   ref_map,
+                                         const char    *ref,
+                                         VarRefInfoRef *out_info);
 gboolean flatpak_name_matches_one_wildcard_prefix (const char         *string,
                                                    const char * const *maybe_wildcard_prefixes,
                                                    gboolean            require_exact_match);
diff --git a/common/flatpak-utils.c b/common/flatpak-utils.c
index 0bc74133..aa37d79b 100644
--- a/common/flatpak-utils.c
+++ b/common/flatpak-utils.c
@@ -2605,7 +2605,7 @@ flatpak_variant_save (GFile        *dest,
 
 /* This special cases the ref lookup which by doing a
    bsearch since the array is sorted */
-static gboolean
+gboolean
 flatpak_var_ref_map_lookup_ref (VarRefMapRef   ref_map,
                                 const char    *ref,
                                 VarRefInfoRef *out_info)
@@ -3469,6 +3469,7 @@ populate_commit_data_cache (GVariant   *metadata,
   g_autoptr(GVariant) sparse_cache = NULL;
   gsize n, i;
   guint32 cache_version = 0;
+  guint32 summary_version = 0;
   const char *old_collection_id;
 
   if (!g_variant_lookup (metadata, "ostree.summary.collection-id", "&s", &old_collection_id))
@@ -3486,6 +3487,11 @@ populate_commit_data_cache (GVariant   *metadata,
   if (cache_version < FLATPAK_XA_CACHE_VERSION)
     return; /* We need to rebuild the cache with the current version */
 
+  if (g_variant_lookup (metadata, "xa.summary-version", "u", &summary_version))
+    summary_version = GUINT32_FROM_LE (summary_version);
+  else
+    summary_version = 0;
+
   cache = g_variant_get_child_value (cache_v, 0);
 
   sparse_cache = g_variant_lookup_value (metadata, "xa.sparse-cache", NULL);
@@ -3778,11 +3784,33 @@ flatpak_get_arch_for_ref (const char *ref)
   return NULL;
 }
 
+static void
+variant_dict_merge (GVariantDict *dict,
+                    GVariant *to_merge)
+{
+  GVariantIter iter;
+  gchar *key;
+  GVariant *value;
+
+  if (to_merge)
+    {
+      g_variant_iter_init (&iter, to_merge);
+      while (g_variant_iter_next (&iter, "{sv}", &key, &value))
+        {
+          g_variant_dict_insert_value (dict, key, value);
+          g_variant_unref (value);
+          g_free (key);
+        }
+    }
+}
+
 static GVariant *
 generate_summary (OstreeRepo   *repo,
+                  gboolean      compat_format,
                   GHashTable   *refs,
                   GHashTable   *commit_data_cache,
                   GPtrArray    *delta_names,
+                  const char  **summary_arches,
                   const char  **gpg_key_ids,
                   const char   *gpg_homedir,
                   GCancellable *cancellable,
@@ -3805,7 +3833,6 @@ generate_summary (OstreeRepo   *repo,
   g_autofree char *authenticator_name = NULL;
   g_autofree char *gpg_keys = NULL;
   g_auto(GStrv) config_keys = NULL;
-  g_auto(GStrv) summary_arches = NULL;
   g_autoptr(GHashTable) summary_arches_ht = NULL;
   int authenticator_install = -1;
   g_autoptr(GHashTable) commits = NULL;
@@ -3837,7 +3864,6 @@ generate_summary (OstreeRepo   *repo,
       if (g_key_file_has_key (config, "flatpak", "authenticator-install", NULL))
         authenticator_install = g_key_file_get_boolean (config, "flatpak", "authenticator-install", NULL);
 
-      summary_arches = g_key_file_get_string_list (config, "flatpak", "summary-arches", NULL, NULL);
 
       config_keys = g_key_file_get_keys (config, "flatpak", NULL, NULL);
     }
@@ -3976,6 +4002,7 @@ generate_summary (OstreeRepo   *repo,
     {
       const char *ref = l->data;
       const char *rev = g_hash_table_lookup (refs, ref);
+      const CommitData *rev_data = NULL;
       g_auto(GVariantDict) commit_metadata_builder = FLATPAK_VARIANT_BUILDER_INITIALIZER;
       g_autoptr(GVariant) commit_obj = NULL;
 
@@ -3985,18 +4012,10 @@ generate_summary (OstreeRepo   *repo,
       if (!ostree_repo_load_variant (repo, OSTREE_OBJECT_TYPE_COMMIT, rev, &commit_obj, error))
         return NULL;
 
-      g_variant_dict_init (&commit_metadata_builder, NULL);
-      g_variant_builder_add_value (refs_builder,
-                                   g_variant_new ("(s(t@ay@a{sv}))", ref,
-                                                  (guint64) g_variant_get_size (commit_obj),
-                                                  ostree_checksum_to_bytes_v (rev),
-                                                  g_variant_dict_end (&commit_metadata_builder)));
-
       /* Only add CommitData for flatpak refs */
       if (is_flatpak_ref (ref))
         {
-          const CommitData *rev_data = g_hash_table_lookup (commit_data_cache, rev);
-
+          rev_data = g_hash_table_lookup (commit_data_cache, rev);
           if (rev_data == NULL)
             {
               rev_data = read_commit_data (repo, ref, rev, cancellable, error);
@@ -4005,7 +4024,25 @@ generate_summary (OstreeRepo   *repo,
 
               g_hash_table_insert (commit_data_cache, g_strdup (rev), (CommitData *)rev_data);
             }
+        }
 
+      g_variant_dict_init (&commit_metadata_builder, NULL);
+      if (!compat_format && rev_data)
+        {
+          g_variant_dict_insert (&commit_metadata_builder, "xa.data", "(tts)",
+                                 GUINT64_TO_BE (rev_data->installed_size),
+                                 GUINT64_TO_BE (rev_data->download_size),
+                                 rev_data->metadata_contents);
+          variant_dict_merge (&commit_metadata_builder, rev_data->sparse_data);
+        }
+      g_variant_builder_add_value (refs_builder,
+                                   g_variant_new ("(s(t@ay@a{sv}))", ref,
+                                                  (guint64) g_variant_get_size (commit_obj),
+                                                  ostree_checksum_to_bytes_v (rev),
+                                                  g_variant_dict_end (&commit_metadata_builder)));
+
+      if (compat_format && rev_data)
+        {
           g_variant_builder_add (ref_data_builder, "{s(tts)}",
                                  ref,
                                  GUINT64_TO_BE (rev_data->installed_size),
@@ -4017,48 +4054,57 @@ generate_summary (OstreeRepo   *repo,
         }
     }
 
-  {
-    g_auto(GVariantDict) deltas_builder = FLATPAK_VARIANT_BUILDER_INITIALIZER;
+  if (delta_names)
+    {
+      g_auto(GVariantDict) deltas_builder = FLATPAK_VARIANT_BUILDER_INITIALIZER;
 
-    g_variant_dict_init (&deltas_builder, NULL);
-    for (guint i = 0; i < delta_names->len; i++)
-      {
-        g_autofree char *from = NULL;
-        g_autofree char *to = NULL;
-        GVariant *digest;
+      g_variant_dict_init (&deltas_builder, NULL);
+      for (guint i = 0; i < delta_names->len; i++)
+        {
+          g_autofree char *from = NULL;
+          g_autofree char *to = NULL;
+          GVariant *digest;
 
-        _ostree_parse_delta_name (delta_names->pdata[i], &from, &to);
+          _ostree_parse_delta_name (delta_names->pdata[i], &from, &to);
 
-        /* Only keep deltas going to a ref that is in the summary
-         * (i.e. not arch filtered or random) */
-        if (!g_hash_table_contains (commits, to))
-          continue;
+          /* Only keep deltas going to a ref that is in the summary
+           * (i.e. not arch filtered or random) */
+          if (!g_hash_table_contains (commits, to))
+            continue;
 
-        digest = _ostree_repo_static_delta_superblock_digest (repo,
-                                                              (from && from[0]) ? from : NULL,
-                                                              to, cancellable, error);
-        if (digest == NULL)
-          return FALSE;
+          digest = _ostree_repo_static_delta_superblock_digest (repo,
+                                                                (from && from[0]) ? from : NULL,
+                                                                to, cancellable, error);
+          if (digest == NULL)
+            return FALSE;
 
-        g_variant_dict_insert_value (&deltas_builder, delta_names->pdata[i], digest);
-      }
+          g_variant_dict_insert_value (&deltas_builder, delta_names->pdata[i], digest);
+        }
 
-    if (delta_names->len > 0)
-      g_variant_builder_add (metadata_builder, "{sv}", "ostree.static-deltas", g_variant_dict_end (&deltas_builder));
-  }
+      if (delta_names->len > 0)
+        g_variant_builder_add (metadata_builder, "{sv}", "ostree.static-deltas", g_variant_dict_end (&deltas_builder));
+    }
 
-  /* Note: xa.cache doesn’t need to support collection IDs for the refs listed
-   * in it, because the xa.cache metadata is stored on the ostree-metadata ref,
-   * which is itself strongly bound to a collection ID — so that collection ID
-   * is bound to all the refs in xa.cache. If a client is using the xa.cache
-   * data from a summary file (rather than an ostree-metadata branch), they are
-   * too old to care about collection IDs anyway. */
-  g_variant_builder_add (metadata_builder, "{sv}", "xa.cache",
-                         g_variant_new_variant (g_variant_builder_end (ref_data_builder)));
+  if (compat_format)
+    {
+      /* Note: xa.cache doesn’t need to support collection IDs for the refs listed
+       * in it, because the xa.cache metadata is stored on the ostree-metadata ref,
+       * which is itself strongly bound to a collection ID — so that collection ID
+       * is bound to all the refs in xa.cache. If a client is using the xa.cache
+       * data from a summary file (rather than an ostree-metadata branch), they are
+       * too old to care about collection IDs anyway. */
+      g_variant_builder_add (metadata_builder, "{sv}", "xa.cache",
+                             g_variant_new_variant (g_variant_builder_end (ref_data_builder)));
+      g_variant_builder_add (metadata_builder, "{sv}", "xa.sparse-cache",
+                             g_variant_builder_end (ref_sparse_data_builder));
+    }
+  else
+    {
+      g_variant_builder_add (metadata_builder, "{sv}", "xa.summary-version",
+                             g_variant_new_uint32 (GUINT32_TO_LE (FLATPAK_XA_SUMMARY_VERSION)));
+    }
   g_variant_builder_add (metadata_builder, "{sv}", "xa.cache-version",
                          g_variant_new_uint32 (GUINT32_TO_LE (FLATPAK_XA_CACHE_VERSION)));
-  g_variant_builder_add (metadata_builder, "{sv}", "xa.sparse-cache",
-                         g_variant_builder_end (ref_sparse_data_builder));
 
   g_variant_builder_add_value (summary_builder, g_variant_builder_end (refs_builder));
   g_variant_builder_add_value (summary_builder, g_variant_builder_end (metadata_builder));
@@ -4091,9 +4137,13 @@ flatpak_repo_update (OstreeRepo   *repo,
   g_autoptr(GVariant) old_summary = NULL;
   g_autoptr(GVariant) new_summary = NULL;
   g_autoptr(GPtrArray) delta_names = NULL;
+  g_auto(GStrv) summary_arches = NULL;
   g_autoptr(GHashTable) refs = NULL;
+  GKeyFile *config;
   int repo_dfd;
 
+  config = ostree_repo_get_config (repo);
+
   if (!ostree_repo_list_refs_ext (repo, NULL, &refs,
                                   OSTREE_REPO_LIST_REFS_EXT_EXCLUDE_REMOTES | OSTREE_REPO_LIST_REFS_EXT_EXCLUDE_MIRRORS,
                                   cancellable, error))
@@ -4112,7 +4162,10 @@ flatpak_repo_update (OstreeRepo   *repo,
   if (!ostree_repo_list_static_delta_names (repo, &delta_names, cancellable, error))
     return FALSE;
 
-  new_summary = generate_summary (repo, refs, commit_data_cache, delta_names,
+  if (config)
+    summary_arches = g_key_file_get_string_list (config, "flatpak", "summary-arches", NULL, NULL);
+
+  new_summary = generate_summary (repo, TRUE, refs, commit_data_cache, delta_names, (const char **)summary_arches,
                                   gpg_key_ids, gpg_homedir, cancellable, error);
   if (new_summary == NULL)
     return FALSE;