element.py: Handle uncached state in _push()

This allows proper error handling when pushing an uncached element
should result in a failure (bst artifact push), not a skipped job
(bst build).

1 files changed, 7 insertions, 1 deletions

diff --git a/src/buildstream/element.py b/src/buildstream/element.py
index 5118f0193..ff7dcbbbb 100644
--- a/src/buildstream/element.py
+++ b/src/buildstream/element.py
@@ -1999,7 +1999,13 @@ class Element(Plugin):
     #           and no updated was required
     #
     def _push(self):
-        self.__assert_cached()
+        if not self._cached():
+            raise ElementError("Push failed: {} is not cached".format(self.name))
+
+        # Do not push elements that are cached with a dangling buildtree ref
+        # unless element type is expected to have an an empty buildtree directory
+        if not self._cached_buildtree() and self._buildtree_exists():
+            raise ElementError("Push failed: buildtree of {} is not cached".format(self.name))
 
         if self.__get_tainted():
             self.warn("Not pushing tainted artifact.")