Fix PandasColumn equality wrongly matching non-string values

Author: JosueNina

Common/PandasMapper.py

@@ -37,7 +37,10 @@ def __new__(cls, key):
 
     def __eq__(self, other):
         # We need this since Lean created data frames might contain Symbol objects in the indexes
-        return super().__eq__(other) and type(other) is not Symbol
+        if type(other) is Symbol:
+            return False
+        # For non-strings str.__eq__ returns NotImplemented, which Python resolves to False
+        return super().__eq__(other)
 
     def __hash__(self):
         return super().__hash__()

Tests/Python/PandasIndexingTests.cs

@@ -85,5 +85,17 @@ public void ExpectedException()
                 Assert.IsTrue(exception.Contains("No key found for either mapped or original key.", StringComparison.InvariantCulture), exception);
             }
         }
+
+        [Test]
+        public void ColumnEqualsOnlyMatchingString()
+        {
+            using (Py.GIL())
+            {
+                PyObject result = _pandasDataFrameTests.test_column_equals_only_matching_string();
+                var test = result.As<bool>();
+
+                Assert.IsTrue(test);
+            }
+        }
     }
 }

Tests/Python/PandasTests/PandasIndexingTests.py

@@ -14,6 +14,7 @@
 from AlgorithmImports import *
 from QuantConnect.Tests import *
 from QuantConnect.Tests.Python import *
+from PandasMapper import PandasColumn
 
 # TODO: Rename to PandasResearchTests and keep this class for QB related tests; rename py module to PandasTests
 class PandasIndexingTests():
@@ -68,3 +69,8 @@ def test_contains_user_defined_columns_with_spaces(self, column_name):
             return True
         except:
             return False
+
+    def test_column_equals_only_matching_string(self):
+        # A column label should only equal a matching string, never None/ints/floats
+        column = PandasColumn("shares")
+        return (not (column == None)) and (not (column == 0)) and (not (column == 123)) and (column == "shares")