loadContents and empty value (NEEDS TEST)

Author: mr-c

cwltool/workflow_job.py

@@ -633,7 +633,7 @@ def postScatterEval(io: CWLObjectType) -> CWLObjectType | None:
 
                 fs_access = getdefault(runtimeContext.make_fs_access, StdFsAccess)("")
                 for k, v in io.items():
-                    if k in loadContents:
+                    if k in loadContents and v is not None:
                         val = cast(CWLObjectType, v)
                         if val.get("contents") is None:
                             with fs_access.open(cast(str, val["location"]), "rb") as f: