FIX Do not reset for non-fit in multiclass (#20205)

thomasjpfan · web-flow · commit 007da8db4a90 · 2021-06-09T16:49:58.000+02:00
diff --git a/sklearn/multiclass.py b/sklearn/multiclass.py
@@ -114,25 +114,34 @@ def _check_estimator(estimator):
 class _ConstantPredictor(BaseEstimator):
 
     def fit(self, X, y):
-        self._check_n_features(X, reset=True)
+        check_params = dict(force_all_finite=False, dtype=None,
+                            ensure_2d=False, accept_sparse=True)
+        self._validate_data(X, y, reset=True,
+                            validate_separately=(check_params, check_params))
         self.y_ = y
         return self
 
     def predict(self, X):
         check_is_fitted(self)
-        self._check_n_features(X, reset=True)
+        self._validate_data(X, force_all_finite=False, dtype=None,
+                            accept_sparse=True,
+                            ensure_2d=False, reset=False)
 
         return np.repeat(self.y_, _num_samples(X))
 
     def decision_function(self, X):
         check_is_fitted(self)
-        self._check_n_features(X, reset=True)
+        self._validate_data(X, force_all_finite=False, dtype=None,
+                            accept_sparse=True,
+                            ensure_2d=False, reset=False)
 
         return np.repeat(self.y_, _num_samples(X))
 
     def predict_proba(self, X):
         check_is_fitted(self)
-        self._check_n_features(X, reset=True)
+        self._validate_data(X, force_all_finite=False, dtype=None,
+                            accept_sparse=True,
+                            ensure_2d=False, reset=False)
 
         return np.repeat([np.hstack([1 - self.y_, self.y_])],
                          _num_samples(X), axis=0)
