FIX Validate estimators in Voting{Classifier,Regressor} (#30649)

thomasjpfan · OmarManzoor · web-flow · commit f09c7d94c54a · 2025-01-21T05:18:42.000+01:00
Co-authored-by: Omar Salman &lt;omar.salman2007@gmail.com&gt;
diff --git a/doc/whats_new/upcoming_changes/sklearn.ensemble/30649.fix.rst b/doc/whats_new/upcoming_changes/sklearn.ensemble/30649.fix.rst
@@ -0,0 +1,2 @@
+- :class:`ensemble.VotingClassifier` and :class:`ensemble.VotingRegressor`
+  validate `estimators` to make sure it is a list of tuples. By `Thomas Fan`_.
diff --git a/sklearn/ensemble/_base.py b/sklearn/ensemble/_base.py
@@ -211,7 +211,10 @@ def __init__(self, estimators):
         self.estimators = estimators
 
     def _validate_estimators(self):
-        if len(self.estimators) == 0:
+        if len(self.estimators) == 0 or not all(
+            isinstance(item, (tuple, list)) and isinstance(item[0], str)
+            for item in self.estimators
+        ):
             raise ValueError(
                 "Invalid 'estimators' attribute, 'estimators' should be a "
                 "non-empty list of (string, estimator) tuples."
diff --git a/sklearn/ensemble/tests/test_voting.py b/sklearn/ensemble/tests/test_voting.py
@@ -52,6 +52,14 @@
             {"estimators": []},
             "Invalid 'estimators' attribute, 'estimators' should be a non-empty list",
         ),
+        (
+            {"estimators": [LogisticRegression()]},
+            "Invalid 'estimators' attribute, 'estimators' should be a non-empty list",
+        ),
+        (
+            {"estimators": [(213, LogisticRegression())]},
+            "Invalid 'estimators' attribute, 'estimators' should be a non-empty list",
+        ),
         (
             {"estimators": [("lr", LogisticRegression())], "weights": [1, 2]},
             "Number of `estimators` and weights must be equal",

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+- :class:`ensemble.VotingClassifier` and :class:`ensemble.VotingRegressor`
	`2`	+ validate `estimators` to make sure it is a list of tuples. By `Thomas Fan`_.