show: Print an error message if commit doesn't have detached metadata

...instead of segfaulting.

diff --git a/src/ostree/ot-builtin-show.c b/src/ostree/ot-builtin-show.c
index 09aaead7fa21cf12530fa03ae21e911ef33ac3c6..859c3d149970a021d2733fdd3b70ab95b03e09b2 100644 (file)
--- a/src/ostree/ot-builtin-show.c
+++ b/src/ostree/ot-builtin-show.c
@@ -124,6 +124,12 @@ do_print_metadata_key (OstreeRepo     *repo,
       if (!ostree_repo_read_commit_detached_metadata (repo, resolved_rev, &metadata,
                                                       NULL, error))
         goto out;
+      if (metadata == NULL)
+        {
+          g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND,
+                       "No detached metadata for commit %s", resolved_rev);
+          goto out;
+        }
     }
   
   if (!g_variant_lookup (metadata, key, "&s", &value))