Merge "Fix stack preview"

1 files changed, 11 insertions, 1 deletions

diff --git a/heat/engine/translation.py b/heat/engine/translation.py
index ec5b6bd1a..d890da54c 100644
--- a/heat/engine/translation.py
+++ b/heat/engine/translation.py
@@ -11,6 +11,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_utils import encodeutils
+
+from heat.common import exception
 from heat.common.i18n import _
 from heat.engine.cfn import functions as cfn_funcs
 from heat.engine import function
@@ -154,7 +157,14 @@ class TranslationRule(object):
             if isinstance(param, hot_funcs.Removed):
                 raise AttributeError(_('Property uses removed function.'))
             if isinstance(param, (hot_funcs.GetParam, cfn_funcs.ParamRef)):
-                return function.resolve(param)
+                try:
+                    return function.resolve(param)
+                except exception.UserParameterMissing as ex:
+                    # We can't resolve parameter now. Abort translation.
+                    err_msg = encodeutils.exception_to_unicode(ex)
+                    raise AttributeError(
+                        _('Can not resolve parameter '
+                          'due to: %s') % err_msg)
             elif isinstance(param, list):
                 return [resolve_param(param_item) for param_item in param]
             else: