Unpack dictionary parameters

RELEASE.md

@@ -2,6 +2,7 @@
 
 ## Major features and improvements
 * Kedro commands are now lazily loaded to add performance gains when running Kedro commands.
+* Can use unpacking with parameter dictionaries.
 
 ## Bug fixes and other changes
 * Updated error message for invalid catalog entries.
@@ -22,6 +23,8 @@
 * Extended documentation with an example of logging customisation at runtime
 
 ## Community contributions
+Many thanks to the following Kedroids for contributing PRs to this release:
+* [bpmeek](https://github.com/bpmeek/)
 
 # Release 0.19.6
 

kedro/pipeline/modular_pipeline.py

@@ -123,7 +123,11 @@ def _get_dataset_names_mapping(
 
 def _normalize_param_name(name: str) -> str:
     """Make sure that a param name has a `params:` prefix before passing to the node"""
-    return name if name.startswith("params:") else f"params:{name}"
+    return (
+        name
+        if name.startswith("params:") or name.startswith("**params:")
+        else f"params:{name}"
+    )
 
 
 def _get_param_names_mapping(
@@ -251,6 +255,11 @@ def _map_transcode_base(name: str) -> str:
         base_name, transcode_suffix = _transcode_split(name)
         return TRANSCODING_SEPARATOR.join((mapping[base_name], transcode_suffix))
 
+    def _matches_unpackable(name: str) -> bool:
+        param_base = name.split(".")[0]
+        matches = [True for key, value in mapping.items() if f"**{param_base}" in key]
+        return any(matches)
+
     def _rename(name: str) -> str:
         rules = [
             # if name mapped to new name, update with new name
@@ -259,6 +268,8 @@ def _rename(name: str) -> str:
             (_is_all_parameters, lambda n: n),
             # if transcode base is mapped to a new name, update with new base
             (_is_transcode_base_in_mapping, _map_transcode_base),
+            # if name refers to dictionary to be unpacked, leave as is
+            (lambda n: _matches_unpackable(name), lambda n: n),
             # if name refers to a single parameter and a namespace is given, apply prefix
             (lambda n: bool(namespace) and _is_single_parameter(n), _prefix_param),
             # if namespace given for a dataset, prefix name using that namespace

kedro/pipeline/node.py

@@ -119,6 +119,8 @@ def __init__(  # noqa: PLR0913
                 _node_error_message("it must have some 'inputs' or 'outputs'.")
             )
 
+        inputs = _unpacked_params(func, inputs)
+
         self._validate_inputs(func, inputs)
 
         self._func = func
@@ -683,3 +685,31 @@ def _get_readable_func_name(func: Callable) -> str:
         name = "<partial>"
 
     return name
+
+
+def _unpacked_params(
+    func: Callable, inputs: None | str | list[str] | dict[str, str]
+) -> None | str | list[str] | dict[str, str]:
+    """Iterate over Node inputs to see if they need to be unpacked.
+
+    Returns:
+        Either original inputs if no input was unpacked or a list of inputs if an input was unpacked.
+    """
+    use_new = False
+    new_inputs = []
+    _func_arguments = [arg for arg in inspect.signature(func).parameters]
+    for idx, _input in enumerate(_to_list(inputs)):
+        if _input.startswith("**params"):
+            if "**" in str(inspect.signature(func)):
+                raise TypeError(
+                    "Function side dictionary unpacking is currently incompatible with parameter dictionary unpacking."
+                )
+            use_new = True
+            dict_root = _input.split(":")[-1]
+            for param in _func_arguments[idx:]:
+                new_inputs.append(f"params:{dict_root}.{param}")
+        else:
+            new_inputs.append(_input)
+    if use_new:
+        return new_inputs
+    return inputs

tests/pipeline/test_node.py

@@ -24,6 +24,14 @@ def triconcat(input1: str, input2: str, input3: str):
     return input1 + input2 + input3  # pragma: no cover
 
 
+def dict_unpack():
+    return dict(input2="input2", input3="another node")
+
+
+def kwargs_input(**kwargs):
+    return kwargs
+
+
 @pytest.fixture
 def simple_tuple_node_list():
     return [
@@ -125,6 +133,47 @@ def test_inputs_list(self):
         )
         assert dummy_node.inputs == ["input1", "input2", "another node"]
 
+    def test_inputs_unpack_str(self):
+        dummy_node = node(triconcat, inputs="**params:dict_unpack", outputs="output1")
+        assert dummy_node.inputs == [
+            "params:dict_unpack.input1",
+            "params:dict_unpack.input2",
+            "params:dict_unpack.input3",
+        ]
+
+    def test_inputs_unpack_list(self):
+        dummy_node = node(
+            triconcat,
+            inputs=["input1", "**params:dict_unpack"],
+            outputs=["output1", "output2", "last node"],
+        )
+        assert dummy_node.inputs == [
+            "input1",
+            "params:dict_unpack.input2",
+            "params:dict_unpack.input3",
+        ]
+
+    def test_inputs_unpack_dict(self):
+        dummy_node = node(
+            triconcat,
+            inputs={"input1": "**params:dict_unpack"},
+            outputs=["output1", "output2", "last node"],
+        )
+        assert dummy_node.inputs == [
+            "params:dict_unpack.input1",
+            "params:dict_unpack.input2",
+            "params:dict_unpack.input3",
+        ]
+
+    def test_kwargs_node_negative(self):
+        pattern = "parameter dictionary unpacking"
+        with pytest.raises(TypeError, match=pattern):
+            node(
+                kwargs_input,
+                inputs="**params:dict_unpack",
+                outputs="output1",
+            )
+
     def test_outputs_none(self):
         dummy_node = node(identity, "input", None)
         assert dummy_node.outputs == []