pull: Allow disabling commit binding verification

In some cases such as backups or mirroring you may want to pull commits
from one repo to another even if there commits that have incorrect
bindings. Fixing the commits in the source repository to have correct
bindings may not be feasible, so provide a pull option to disable
verification.

For Endless we have several repositories that predate collection IDs and
ref bindings. Later these repositories gained collection IDs to support
the features they provide and ref bindings as the ostree tooling was
upgraded. These repositories contain released commits that were valid to
the clients they were targeting at the time. Correcting the bindings is
not really an option as it would mean invalidating the repository
history.

src/libostree/ostree-repo-pull.c

@@ -1620,15 +1620,17 @@ scan_commit_object (OtPullData                 *pull_data,
   if (!ostree_repo_load_commit (pull_data->repo, checksum, &commit, &commitstate, error))
     return FALSE;
 
-  /* If ref is non-NULL then the commit we fetched was requested through the
-   * branch, otherwise we requested a commit checksum without specifying a branch.
-   */
-  g_autofree char *remote_collection_id = NULL;
-  remote_collection_id = get_remote_repo_collection_id (pull_data);
-  if (!_ostree_repo_verify_bindings (remote_collection_id,
-                                     (ref != NULL) ? ref->ref_name : NULL,
-                                     commit, error))
-    return glnx_prefix_error (error, "Commit %s", checksum);
+  if (!pull_data->disable_verify_bindings) {
+    /* If ref is non-NULL then the commit we fetched was requested through the
+     * branch, otherwise we requested a commit checksum without specifying a branch.
+     */
+    g_autofree char *remote_collection_id = NULL;
+    remote_collection_id = get_remote_repo_collection_id (pull_data);
+    if (!_ostree_repo_verify_bindings (remote_collection_id,
+                                       (ref != NULL) ? ref->ref_name : NULL,
+                                       commit, error))
+      return glnx_prefix_error (error, "Commit %s", checksum);
+  }
 
   guint64 new_ts = ostree_commit_get_timestamp (commit);
   if (pull_data->timestamp_check)
@@ -3670,6 +3672,8 @@ all_requested_refs_have_commit (GHashTable *requested_refs /* (element-type Ostr
  *     specified, the `summary` will be downloaded from the remote. Since: 2020.5
  *   * `summary-sig-bytes` (`ay`): Contents of the `summary.sig` file. If this
  *     is specified, `summary-bytes` must also be specified. Since: 2020.5
+ *   * `disable-verify-bindings` (`b`): Disable verification of commit bindings.
+ *     Since: 2020.9
  */
 gboolean
 ostree_repo_pull_with_options (OstreeRepo             *self,
@@ -3771,6 +3775,7 @@ ostree_repo_pull_with_options (OstreeRepo             *self,
 	g_variant_lookup (options, "ref-keyring-map", "a(sss)", &ref_keyring_map_iter);
       (void) g_variant_lookup (options, "summary-bytes", "@ay", &summary_bytes_v);
       (void) g_variant_lookup (options, "summary-sig-bytes", "@ay", &summary_sig_bytes_v);
+      (void) g_variant_lookup (options, "disable-verify-bindings", "b", &pull_data->disable_verify_bindings);
 
       if (pull_data->remote_refspec_name != NULL)
         pull_data->remote_name = g_strdup (pull_data->remote_refspec_name);