Bug Fix: argument names should override captured variables (#100)

* Fixes a bug that is part of captured variables logic
* If `jets` was used as both a lambda argument an a global constant, then it would be replaced by its value in the AST

Fixes #95

Author: gordonwatts

func_adl/util_ast.py

@@ -322,14 +322,28 @@ class _rewrite_captured_vars(ast.NodeTransformer):
     def __init__(self, cv: inspect.ClosureVars):
         self._lookup_dict: Dict[str, Any] = dict(cv.nonlocals)
         self._lookup_dict.update(cv.globals)
+        self._ignore_stack = []
 
     def visit_Name(self, node: ast.Name) -> Any:
+        if self.is_arg(node.id):
+            return node
+
         if node.id in self._lookup_dict:
             v = self._lookup_dict[node.id]
             if not callable(v):
                 return as_literal(self._lookup_dict[node.id])
         return node
 
+    def visit_Lambda(self, node: ast.Lambda) -> Any:
+        self._ignore_stack.append([a.arg for a in node.args.args])
+        v = super().generic_visit(node)
+        self._ignore_stack.pop()
+        return v
+
+    def is_arg(self, a_name: str) -> bool:
+        "If the arg is on the stack, then return true"
+        return any([a == a_name for frames in self._ignore_stack for a in frames])
+
 
 def global_getclosurevars(f: Callable) -> inspect.ClosureVars:
     """Grab the closure over all passed function. Add all known global

tests/test_util_ast.py

@@ -279,9 +279,23 @@ def test_parse_lambda_capture():
     assert ast.dump(r) == ast.dump(r_true)
 
 
+def test_parse_lambda_capture_ignore_local():
+    x = 30  # NOQA type: ignore
+    r = parse_as_ast(lambda x: x > 20)
+    r_true = parse_as_ast(lambda y: y > 20)
+    assert ast.dump(r) == ast.dump(r_true).replace("'y'", "'x'")
+
+
 g_cut_value = 30
 
 
+def test_parse_lambda_capture_ignore_global():
+    x = 30  # NOQA type: ignore
+    r = parse_as_ast(lambda g_cut_value: g_cut_value > 20)
+    r_true = parse_as_ast(lambda y: y > 20)
+    assert ast.dump(r) == ast.dump(r_true).replace("'y'", "'g_cut_value'")
+
+
 def test_parse_lambda_capture_nested_global():
     r = parse_as_ast(lambda x: (lambda y: y > g_cut_value)(x))
     r_true = parse_as_ast(lambda x: (lambda y: y > 30)(x))