fix reconstruction of null (#198)

this fixes #195

Author: kkozik-amplify

hcl2/reconstructor.py

@@ -540,6 +540,12 @@ def _transform_value_to_expr_term(self, value, level) -> Union[Token, Tree]:
             )
             return Tree(Token("RULE", "expr_term"), [tuple_tree])
 
+        if value is None:
+            return Tree(
+                Token("RULE", "expr_term"),
+                [Tree(Token("RULE", "identifier"), [Token("NAME", "null")])],
+            )
+
         # for dicts, recursively turn the child k/v pairs into object elements
         # and store within an object
         if isinstance(value, dict):

test/helpers/terraform-config-json/locals_embedded_condition.json

@@ -3,7 +3,8 @@
     {
       "terraform": {
         "channels": "${local.running_in_ci ? local.ci_channels : local.local_channels}",
-        "authentication": []
+        "authentication": [],
+        "foo": null
       }
     }
   ]

test/helpers/terraform-config/locals_embedded_condition.tf

@@ -2,5 +2,6 @@ locals {
   terraform = {
     channels = (local.running_in_ci ? local.ci_channels : local.local_channels),
     authentication = [],
+    foo = null,
   }
 }

test/unit/test_builder.py

@@ -44,6 +44,7 @@ def test_locals_embdedded_condition_tf(self):
             terraform={
                 "channels": "${local.running_in_ci ? local.ci_channels : local.local_channels}",
                 "authentication": [],
+                "foo": None,
             },
         )