Preserve saved globals when copying DelayEvaluator

metaflow/user_configs/config_parameters.py

@@ -301,17 +301,17 @@ def __init__(self, ex: str, saved_globals: Optional[Dict[str, Any]] = None):
         self._cached_expr = None
 
     def __copy__(self):
-        c = DelayEvaluator(self._config_expr)
+        # Keep caller globals by reference so config_expr("my_func").project still
+        # resolves after attribute/item access (which copies this object).
+        c = DelayEvaluator(self._config_expr, saved_globals=self._globals)
         c._access = self._access.copy() if self._access is not None else None
-        # Globals are not copied -- always kept as a reference
         return c
 
     def __deepcopy__(self, memo):
-        c = DelayEvaluator(self._config_expr)
+        c = DelayEvaluator(self._config_expr, saved_globals=self._globals)
         c._access = (
             copy.deepcopy(self._access, memo) if self._access is not None else None
         )
-        # Globals are not copied -- always kept as a reference
         return c
 
     def __iter__(self):

test/unit/test_delay_evaluator.py

@@ -0,0 +1,73 @@
+import copy
+
+from metaflow.flowspec import FlowStateItems
+from metaflow.parameters import current_flow
+from metaflow.user_configs.config_parameters import DelayEvaluator
+
+
+def _sample_globals():
+    def my_func():
+        return "hello"
+
+    return {"my_func": my_func}
+
+
+class _DummyFlow:
+    _flow_state = {FlowStateItems.CONFIGS: {}}
+
+
+def _with_dummy_flow(fn):
+    current_flow.flow_cls = _DummyFlow
+    try:
+        return fn()
+    finally:
+        del current_flow.flow_cls
+
+
+def test_copy_preserves_saved_globals():
+    saved = _sample_globals()
+    evaluator = DelayEvaluator("config", saved_globals=saved)
+    copied = copy.copy(evaluator)
+    assert copied._globals is saved
+    assert copied._globals["my_func"]() == "hello"
+
+
+def test_deepcopy_preserves_saved_globals():
+    saved = _sample_globals()
+    evaluator = DelayEvaluator("config", saved_globals=saved)
+    copied = copy.deepcopy(evaluator)
+    assert copied._globals is saved
+    assert copied._globals["my_func"]() == "hello"
+
+
+def test_getattr_preserves_saved_globals():
+    saved = _sample_globals()
+    evaluator = DelayEvaluator("config", saved_globals=saved)
+    chained = evaluator.project
+    assert chained._globals is saved
+    assert chained._access == ["project"]
+
+
+def test_getitem_preserves_saved_globals():
+    saved = _sample_globals()
+    evaluator = DelayEvaluator("config", saved_globals=saved)
+    chained = evaluator["project"]
+    assert chained._globals is saved
+    assert chained._access == ["project"]
+
+
+def test_chained_call_uses_saved_globals():
+    class _Cfg:
+        project = "from-globals"
+
+    saved = {"my_func": _Cfg}
+    evaluator = DelayEvaluator("my_func", saved_globals=saved)
+    chained = evaluator.project
+    assert _with_dummy_flow(chained) == "from-globals"
+
+
+def test_copied_call_uses_saved_globals():
+    saved = _sample_globals()
+    evaluator = DelayEvaluator("my_func()", saved_globals=saved)
+    copied = copy.copy(evaluator)
+    assert _with_dummy_flow(copied) == "hello"