[ostree] core: Note which artifact failed to compose

[Colin Walters <walters src gnome org>]

commit a6e6146ab641ece005df140e89e5cc1b58db0ced
Author: Colin Walters <walters verbum org>
Date:   Mon Jan 16 09:57:24 2012 -0500

    core: Note which artifact failed to compose

 src/ostree/ot-builtin-compose.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/src/ostree/ot-builtin-compose.c b/src/ostree/ot-builtin-compose.c
index 30d0aec..5019dfa 100644
--- a/src/ostree/ot-builtin-compose.c
+++ b/src/ostree/ot-builtin-compose.c
@@ -75,8 +75,11 @@ add_branch (OstreeRepo          *repo,
 
   if (!ostree_repo_stage_directory_to_mtree (repo, subdir, mtree, NULL,
                                              NULL, error))
-    goto out;
-  
+    {
+      g_prefix_error (error, "Error composing %s: ", branch_path);
+      goto out;
+    }  
+
   if (metadata_builder)
     g_variant_builder_add (metadata_builder, "(ss)", branch_path, branch_rev);