fix(terraform): Fix conditional expression evaluation logic with comp…

…are (#6160)

* fix(terraform): Fix conditional expression evaluation logic with compare

* filter out None before conversion

---------

Co-authored-by: Steve Vaknin <svaknin@paloaltonetworks.com>

checkov/terraform/graph_builder/variable_rendering/evaluate_terraform.py

@@ -215,7 +215,9 @@ def evaluate_conditional_expression(input_str: str) -> str:
         groups, start, end = condition
         if len(groups) != 3:
             return input_str
-        evaluated_condition = evaluate_terraform(groups[0])
+        evaluated_condition = evaluate_compare(groups[0])
+        if type(evaluated_condition) is str:
+            evaluated_condition = evaluate_terraform(groups[0])
         condition_substr = input_str[start:end]
         bool_evaluated_condition = convert_to_bool(evaluated_condition)
         if bool_evaluated_condition is True:
@@ -407,12 +409,12 @@ def apply_binary_op(a: Optional[Union[str, int, bool]], b: Optional[Union[str, i
     if type_a != type_b:
         try:
             temp_b = type_a(b)  # type:ignore[misc,arg-type]
-            if isinstance(type_a, bool):
+            if isinstance(a, bool) and b:
                 temp_b = bool(convert_to_bool(b))
             return operators[operator](a, temp_b)  # type:ignore[type-var]
         except Exception:
             temp_a = type_b(a)  # type:ignore[misc,arg-type]
-            if isinstance(type_b, bool):
+            if isinstance(b, bool) and a:
                 temp_a = bool(convert_to_bool(a))
             return operators[operator](temp_a, b)  # type:ignore[type-var]
     else:

tests/terraform/graph/variable_rendering/test_string_evaluation.py

@@ -41,6 +41,14 @@ def test_conditional_expression(self):
         input_str = 'blocked == "allowed" ? True : False'
         expected = False
         self.assertEqual(expected, evaluate_terraform(input_str))
+
+        input_str = 'True == "true" ? True : False'
+        expected = True
+        self.assertEqual(expected, evaluate_terraform(input_str))
+
+        input_str = 'False != "false" ? True : False'
+        expected = False
+        self.assertEqual(expected, evaluate_terraform(input_str))
 
     def test_format(self):
         input_str = '"format("Hello, %s!", "Ander")"'