--- a/mercurial/chgserver.py	Thu Jun 27 11:39:35 2019 +0200
+++ b/mercurial/chgserver.py	Tue Jun 25 19:28:41 2019 -0700
@@ -138,7 +138,9 @@
         modules.append(__version__)
     except ImportError:
         pass
-    files = [pycompat.sysexecutable]
+    files = []
+    if pycompat.sysexecutable:
+        files.append(pycompat.sysexecutable)
     for m in modules:
         try:
             files.append(pycompat.fsencode(inspect.getabsfile(m)))