diff --git a/project.py b/project.py
index 34e9046d..f2f81d7a 100644
--- a/project.py
+++ b/project.py
@@ -1443,6 +1443,8 @@ class Project(object):
         rather than the id of the current git object (for example, a tag)
 
         """
+        if self.revisionId:
+            return self.revisionId
         if not self.revisionExpr.startswith(R_TAGS):
             return self.GetRevisionId(self._allrefs)