Fix map_task sensitive to argument order

flytekit/core/array_node_map_task.py

@@ -270,13 +270,15 @@
             outputs_expected = False
         outputs = []
 
-        any_input_key = (
-            list(self.python_function_task.interface.inputs.keys())[0]
-            if self.python_function_task.interface.inputs.items() is not None
-            else None
-        )
+        mapped_input_value_len = 0
+        if self._run_task.interface.inputs.items():
+            for k in self._run_task.interface.inputs.keys():
+                v = kwargs[k]
+                if isinstance(v, list) and k not in self.bound_inputs:
+                    mapped_input_value_len = len(v)
+                    break
 
-        for i in range(len(kwargs[any_input_key])):
+        for i in range(mapped_input_value_len):
             single_instance_inputs = {}
             for k in self.interface.inputs.keys():
                 v = kwargs[k]

flytekit/core/map_task.py

@@ -263,13 +263,15 @@
             outputs_expected = False
         outputs = []
 
-        any_input_key = (
-            list(self._run_task.interface.inputs.keys())[0]
-            if self._run_task.interface.inputs.items() is not None
-            else None
-        )
+        mapped_input_value_len = 0
+        if self._run_task.interface.inputs.items():
+            for k in self._run_task.interface.inputs.keys():
+                v = kwargs[k]
+                if isinstance(v, list) and k not in self.bound_inputs:
+                    mapped_input_value_len = len(v)
+                    break
 
-        for i in range(len(kwargs[any_input_key])):
+        for i in range(mapped_input_value_len):
             single_instance_inputs = {}
             for k in self.interface.inputs.keys():
                 v = kwargs[k]

tests/flytekit/unit/core/test_array_node_map_task.py

@@ -230,3 +230,27 @@ def many_outputs(a: int) -> (int, str):
 
     with pytest.raises(ValueError):
         _ = array_node_map_task(many_outputs)
+
+
+def test_parameter_order():
+    @task()
+    def task1(a: int, b: float, c: str) -> str:
+        return f"{a} - {b} - {c}"
+
+    @task()
+    def task2(b: float, c: str, a: int) -> str:
+        return f"{a} - {b} - {c}"
+
+    @task()
+    def task3(c: str, a: int, b: float) -> str:
+        return f"{a} - {b} - {c}"
+
+    param_a = [1, 2, 3]
+    param_b = [0.1, 0.2, 0.3]
+    param_c = "c"
+
+    m1 = array_node_map_task(functools.partial(task1, c=param_c))(a=param_a, b=param_b)
+    m2 = array_node_map_task(functools.partial(task2, c=param_c))(a=param_a, b=param_b)
+    m3 = array_node_map_task(functools.partial(task3, c=param_c))(a=param_a, b=param_b)
+
+    assert m1 == m2 == m3 == ["1 - 0.1 - c", "2 - 0.2 - c", "3 - 0.3 - c"]

tests/flytekit/unit/core/test_map_task.py

@@ -282,3 +282,27 @@ def my_wf1() -> typing.List[type_t]:
         return map_task(some_task1, min_success_ratio=min_success_ratio)(inputs=[1, 2, 3, 4])
 
     my_wf1()
+
+
+def test_map_task_parameter_order():
+    @task()
+    def task1(a: int, b: float, c: str) -> str:
+        return f"{a} - {b} - {c}"
+
+    @task()
+    def task2(b: float, c: str, a: int) -> str:
+        return f"{a} - {b} - {c}"
+
+    @task()
+    def task3(c: str, a: int, b: float) -> str:
+        return f"{a} - {b} - {c}"
+
+    param_a = [1, 2, 3]
+    param_b = [0.1, 0.2, 0.3]
+    param_c = "c"
+
+    m1 = map_task(functools.partial(task1, c=param_c))(a=param_a, b=param_b)
+    m2 = map_task(functools.partial(task2, c=param_c))(a=param_a, b=param_b)
+    m3 = map_task(functools.partial(task3, c=param_c))(a=param_a, b=param_b)
+
+    assert m1 == m2 == m3 == ["1 - 0.1 - c", "2 - 0.2 - c", "3 - 0.3 - c"]