--- a/mercurial/context.py	Mon Jun 24 16:07:59 2019 -0700
+++ b/mercurial/context.py	Mon Jun 24 16:01:22 2019 -0700
@@ -2159,7 +2159,9 @@
         # the file is marked as existing.
         if exists and data is None:
             oldentry = self._cache.get(path) or {}
-            data = oldentry.get('data') or self._wrappedctx[path].data()
+            data = oldentry.get('data')
+            if data is None:
+                data = self._wrappedctx[path].data()
 
         self._cache[path] = {
             'exists': exists,