🐛 ✅ Make custom separator work when recursively flattening a dict par…

…ameter even for nested dicts (#230)

CHANGELOG.md

@@ -5,10 +5,11 @@
 ### Fixed
 
 - :bug: Dictionnary parameters with integer keys are now properly logged in mlflow when ``flatten_dict_params`` is set to ``True`` in the ``mlflow.yml`` instead of raising a ``TypeError`` ([#224](https://github.com/Galileo-Galilei/kedro-mlflow/discussions/224))
+- :bug: The user defined ``sep`` parameter of the ``mlflow.yml`` (defined in ``node`` section) is now used even if the parameters dictionnary has a depth>=2 ([#230](https://github.com/Galileo-Galilei/kedro-mlflow/issues/230))
 
 ### Changed
 
-- :recycle: Move ``flatten_dict`` function to ``hooks.utils`` folder and rename it ``_flatten_dict`` to make more explicit that it is not a user facing function which should not be used directly.
+- :recycle: Move ``flatten_dict`` function to ``hooks.utils`` folder and rename it ``_flatten_dict`` to make more explicit that it is not a user facing function which should not be used directly and comes with no guarantee. This is not considered as a breaking change since it is an undocumented function.
 
 
 ## [0.7.3] - 2021-08-16

kedro_mlflow/framework/hooks/utils.py

@@ -19,7 +19,11 @@ def _assert_mlflow_enabled(pipeline_name: str) -> bool:
 def _flatten_dict(d: Dict, recursive: bool = True, sep: str = ".") -> Dict:
     def expand(key, value):
         if isinstance(value, dict):
-            new_value = _flatten_dict(value) if recursive else value
+            new_value = (
+                _flatten_dict(value, recursive=recursive, sep=sep)
+                if recursive
+                else value
+            )
             return [(f"{key}{sep}{k}", v) for k, v in new_value.items()]
         else:
             return [(f"{key}", value)]

tests/framework/hooks/test_utils.py

@@ -64,3 +64,15 @@ def test_flatten_dict_with_float_keys():
             6.7: 5,  # 6.7 is not converted to string, but when the entire dict will be logged mlflow will take care of the conversion
         },
     }
+
+
+def test_flatten_dict_with_used_defined_sep():
+    d = dict(a=1, b=dict(c=1, d=dict(e=3, f=dict(g=4, h=5))))
+
+    assert _flatten_dict(d=d, recursive=True, sep="_") == {
+        "a": 1,
+        "b_c": 1,
+        "b_d_e": 3,
+        "b_d_f_g": 4,
+        "b_d_f_h": 5,
+    }