$ git diff
diff --git a/src/python/pants/engine/legacy/structs.py b/src/python/pants/engine/legacy/structs.py
index 0ee7f14..24e5e98 100644
--- a/src/python/pants/engine/legacy/structs.py
+++ b/src/python/pants/engine/legacy/structs.py
@@ -39,7 +39,7 @@ class TargetAdaptor(StructWithDeps):
       see: <https://github.com/pantsbuild/pants/issues/2997>
     """
     sources = getattr(self, 'sources', None)
-    if not sources:
+    if sources is None:
       if self.default_sources_globs:
         return Globs(*self.default_sources_globs,
                      spec_path=self.address.spec_path,