API Deprecate positional arguments in tree module (scikit-learn#16966)

Author: thomasjpfan

sklearn/tree/_classes.py

@@ -36,6 +36,7 @@
 from ..utils import compute_sample_weight
 from ..utils.multiclass import check_classification_targets
 from ..utils.validation import check_is_fitted
+from ..utils.validation import _deprecate_positional_args
 
 from ._criterion import Criterion
 from ._splitter import Splitter
@@ -82,7 +83,8 @@ class BaseDecisionTree(MultiOutputMixin, BaseEstimator, metaclass=ABCMeta):
     """
 
     @abstractmethod
-    def __init__(self,
+    @_deprecate_positional_args
+    def __init__(self, *,
                  criterion,
                  splitter,
                  max_depth,
@@ -815,7 +817,8 @@ class DecisionTreeClassifier(ClassifierMixin, BaseDecisionTree):
     array([ 1.     ,  0.93...,  0.86...,  0.93...,  0.93...,
             0.93...,  0.93...,  1.     ,  0.93...,  1.      ])
     """
-    def __init__(self,
+    @_deprecate_positional_args
+    def __init__(self, *,
                  criterion="gini",
                  splitter="best",
                  max_depth=None,
@@ -1169,7 +1172,8 @@ class DecisionTreeRegressor(RegressorMixin, BaseDecisionTree):
     array([-0.39..., -0.46...,  0.02...,  0.06..., -0.50...,
            0.16...,  0.11..., -0.73..., -0.30..., -0.00...])
     """
-    def __init__(self,
+    @_deprecate_positional_args
+    def __init__(self, *,
                  criterion="mse",
                  splitter="best",
                  max_depth=None,
@@ -1499,7 +1503,8 @@ class ExtraTreeClassifier(DecisionTreeClassifier):
     >>> cls.score(X_test, y_test)
     0.8947...
     """
-    def __init__(self,
+    @_deprecate_positional_args
+    def __init__(self, *,
                  criterion="gini",
                  splitter="random",
                  max_depth=None,
@@ -1716,7 +1721,8 @@ class ExtraTreeRegressor(DecisionTreeRegressor):
     >>> reg.score(X_test, y_test)
     0.33...
     """
-    def __init__(self,
+    @_deprecate_positional_args
+    def __init__(self, *,
                  criterion="mse",
                  splitter="random",
                  max_depth=None,

sklearn/tree/_export.py

@@ -17,6 +17,7 @@
 import numpy as np
 
 from ..utils.validation import check_is_fitted
+from ..utils.validation import _deprecate_positional_args
 from ..base import is_classifier
 
 from . import _criterion
@@ -77,7 +78,8 @@ def __repr__(self):
 SENTINEL = Sentinel()
 
 
-def plot_tree(decision_tree, max_depth=None, feature_names=None,
+@_deprecate_positional_args
+def plot_tree(decision_tree, *, max_depth=None, feature_names=None,
               class_names=None, label='all', filled=False,
               impurity=True, node_ids=False,
               proportion=False, rotate='deprecated', rounded=False,
@@ -656,7 +658,8 @@ def recurse(self, node, tree, ax, scale_x, scale_y, height, depth=0):
             ax.annotate("\n  (...)  \n", xy_parent, xy, **kwargs)
 
 
-def export_graphviz(decision_tree, out_file=None, max_depth=None,
+@_deprecate_positional_args
+def export_graphviz(decision_tree, out_file=None, *, max_depth=None,
                     feature_names=None, class_names=None, label='all',
                     filled=False, leaves_parallel=False, impurity=True,
                     node_ids=False, proportion=False, rotate=False,
@@ -807,7 +810,8 @@ def compute_depth_(current_node, current_depth,
     return max(depths)
 
 
-def export_text(decision_tree, feature_names=None, max_depth=10,
+@_deprecate_positional_args
+def export_text(decision_tree, *, feature_names=None, max_depth=10,
                 spacing=3, decimals=2, show_weights=False):
     """Build a text report showing the rules of a decision tree.
 

sklearn/tree/tests/test_export.py

@@ -465,6 +465,5 @@ def test_not_fitted_tree(pyplot):
 
     # Testing if not fitted tree throws the correct error
     clf = DecisionTreeRegressor()
-    out = StringIO()
     with pytest.raises(NotFittedError):
-        plot_tree(clf, out)
+        plot_tree(clf)