Fixes regression in which builtins were detected as variables for expr

transition

In the case of `cond.expr("len(foo) > d"), it would expect both len and
foo as keys to the condition. This ignores all builtins.

burr/core/action.py

@@ -1,5 +1,6 @@
 import abc
 import ast
+import builtins
 import copy
 import inspect
 import sys
@@ -204,14 +205,16 @@ def expr(expr: str) -> "Condition":
         :return: A condition that evaluates the given expression
         """
         tree = ast.parse(expr, mode="eval")
+        all_builtins = builtins.__dict__
 
         # Visitor class to collect variable names
         class NameVisitor(ast.NodeVisitor):
             def __init__(self):
                 self.names = set()
 
             def visit_Name(self, node):
-                self.names.add(node.id)
+                if node.id not in all_builtins:
+                    self.names.add(node.id)
 
         # Visit the nodes and collect variable names
         visitor = NameVisitor()
@@ -261,6 +264,9 @@ def condition_func(state: State) -> bool:
         name = f"{', '.join(f'{key}={value}' for key, value in sorted(kwargs.items()))}"
         return Condition(keys, condition_func, name=name)
 
+    def __repr__(self):
+        return f"condition: {self._name}"
+
     @classmethod
     @property
     def default(self) -> "Condition":

tests/core/test_action.py

@@ -120,8 +120,8 @@ def test_condition_expr():
 
 
 def test_condition_expr_complex():
-    cond = Condition.expr("foo == 'bar' and baz == 'qux'")
-    assert cond.name == "foo == 'bar' and baz == 'qux'"
+    cond = Condition.expr("foo == 'bar' and len(baz) == 3")
+    assert cond.name == "foo == 'bar' and len(baz) == 3"
     assert sorted(cond.reads) == ["baz", "foo"]
     assert cond.run(State({"foo": "bar", "baz": "qux"})) == {Condition.KEY: True}
     assert cond.run(State({"foo": "baz", "baz": "qux"})) == {Condition.KEY: False}