[ostree] log: Print a friendly error if we haven't downloaded the complete history

[Colin Walters <walters src gnome org>]

commit 4ac27caefd30aa10f2a82cc38bf9e8df095619e0
Author: Colin Walters <walters verbum org>
Date:   Wed Jun 11 16:40:50 2014 -0400

    log: Print a friendly error if we haven't downloaded the complete history
    
    For the local repository on the system, it's not the usual case to
    have the complete compose history.  Rather than erroring out, provide
    a bit more friendly message.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=731538

 src/ostree/ot-builtin-log.c |   23 +++++++++++++++++++----
 1 files changed, 19 insertions(+), 4 deletions(-)
---
diff --git a/src/ostree/ot-builtin-log.c b/src/ostree/ot-builtin-log.c
index 0ab134c..89445cd 100644
--- a/src/ostree/ot-builtin-log.c
+++ b/src/ostree/ot-builtin-log.c
@@ -37,21 +37,36 @@ static GOptionEntry options[] = {
 static gboolean
 log_commit (OstreeRepo     *repo,
             const gchar    *checksum,
+            gboolean        is_recurse,
             OstreeDumpFlags flags,
             GError        **error)
 {
   gs_unref_variant GVariant *variant = NULL;
   gs_free gchar *parent = NULL;
   gboolean ret = FALSE;
+  GError *local_error = NULL;
 
-  if (!ostree_repo_load_variant (repo, OSTREE_OBJECT_TYPE_COMMIT, checksum, &variant, error))
-    goto out;
+  if (!ostree_repo_load_variant (repo, OSTREE_OBJECT_TYPE_COMMIT, checksum,
+                                 &variant, &local_error))
+    {
+      if (is_recurse && g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))
+        {
+          g_print ("<< History beyond this commit not fetched >>\n");
+          g_clear_error (&local_error);
+          ret = TRUE;
+        }
+      else
+        {
+          g_propagate_error (error, local_error);
+        }
+      goto out;
+    }
 
   ot_dump_object (OSTREE_OBJECT_TYPE_COMMIT, checksum, variant, flags);
 
   /* Get the parent of this commit */
   parent = ostree_commit_get_parent (variant);
-  if (parent && !log_commit (repo, parent, flags, error))
+  if (parent && !log_commit (repo, parent, TRUE, flags, error))
     goto out;
 
   ret = TRUE;
@@ -91,7 +106,7 @@ ostree_builtin_log (int           argc,
   if (!ostree_repo_resolve_rev (repo, rev, FALSE, &checksum, error))
     goto out;
 
-  if (!log_commit (repo, checksum, flags, error))
+  if (!log_commit (repo, checksum, FALSE, flags, error))
     goto out;
 
   ret = TRUE;