Fixes does function wrapping #244

hamilton/function_modifiers.py

@@ -744,7 +744,8 @@ def generate_node(self, fn: Callable, config) -> node.Node:
         and the same parameters/types as the original function.
         """
 
-        def replacing_function(__fn=fn, **kwargs):
+        @functools.wraps(fn)
+        def wrapper_function(**kwargs):
             final_kwarg_values = {
                 key: param_spec.default
                 for key, param_spec in inspect.signature(fn).parameters.items()
@@ -754,7 +755,7 @@ def replacing_function(__fn=fn, **kwargs):
             final_kwarg_values = does.map_kwargs(final_kwarg_values, self.argument_mapping)
             return self.replacing_function(**final_kwarg_values)
 
-        return node.Node.from_fn(fn).copy_with(callabl=replacing_function)
+        return node.Node.from_fn(fn).copy_with(callabl=wrapper_function)
 
 
 class dynamic_transform(function_modifiers_base.NodeCreator):

tests/resources/multiple_decorators_together.py

@@ -0,0 +1,14 @@
+import pandas as pd
+
+from hamilton.function_modifiers import does, extract_columns
+
+
+def _sum_multiply(param0: int, param1: int, param2: int) -> pd.DataFrame:
+    return pd.DataFrame([{"param0a": param0, "param1b": param1, "param2c": param2}])
+
+
+@extract_columns("param1b")
+@does(_sum_multiply)
+def to_modify(param0: int, param1: int, param2: int = 2) -> pd.DataFrame:
+    """This sums the inputs it gets..."""
+    pass

tests/test_graph.py

@@ -14,6 +14,7 @@
 import tests.resources.extract_columns_execution_count
 import tests.resources.functions_with_generics
 import tests.resources.layered_decorators
+import tests.resources.multiple_decorators_together
 import tests.resources.optional_dependencies
 import tests.resources.parametrized_inputs
 import tests.resources.parametrized_nodes
@@ -359,6 +360,20 @@ def test_end_to_end_with_column_extractor_nodes():
     )
 
 
+def test_end_to_end_with_multiple_decorators():
+    """Tests that a simple function graph with multiple decorators on a function works end-to-end"""
+    fg = graph.FunctionGraph(
+        tests.resources.multiple_decorators_together, config={"param0": 3, "param1": 1}
+    )
+    nodes = fg.get_nodes()
+    results = fg.execute(nodes, {}, {})
+    print(results)
+    df_expected = tests.resources.multiple_decorators_together._sum_multiply(3, 1, 2)
+    pd.testing.assert_series_equal(results["param1b"], df_expected["param1b"])
+    pd.testing.assert_frame_equal(results["to_modify"], df_expected)
+    assert nodes[0].documentation == "This sums the inputs it gets..."
+
+
 def test_end_to_end_with_config_modifier():
     config = {
         "fn_1_version": 1,