Backward compatibility wrapper

checkbox-ng/plainbox/impl/new_resource.py

@@ -219,11 +219,23 @@ def __str__(self):
 
 legacy_getters = {}
 if sys.version_info[0] == 3 and sys.version_info[1] < 8:
-    # older version of python have
+    from collections import namedtuple
+
+    # older version of python have slightly different nodes to parse
+    # constants. Here we wrap them for forward compatibility putting the old
+    # attribute where the ConstantGetter expects to find it
+    Wrapper = namedtuple("Wrapper", ["value"])
+
+    def wrapping(attr):
+        def _f(parsed_ast):
+            wrapped_parsed_ast = Wrapper(getattr(parsed_ast, attr))
+            return ConstantGetter(wrapped_parsed_ast)
+
     legacy_getters = {
-        ast.Str: ConstantGetter,
-        ast.Num: ConstantGetter,
-        ast.Bytes: ConstantGetter,
+        ast.Str: wrapping("s"),
+        ast.Num: wrapping("n"),
+        ast.Bytes: wrapping("s"),
+        # this actually uses .value
         ast.NameConstant: ConstantGetter,
     }