Preserve list values in CSV widget.

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Co-authored-by: Cristian Torres <cris.torres15@gmail.com>

django_filters/widgets.py

@@ -205,6 +205,10 @@ def value_from_datadict(self, data, files, name):
         if value is not None:
             if value == "":  # empty value should parse as an empty list
                 return []
+            if isinstance(value, list):
+                # since django.forms.widgets.SelectMultiple tries to use getlist
+                # if available, we should return value if it's already an array
+                return value
             return value.split(",")
         return None
 

tests/test_widgets.py

@@ -383,6 +383,10 @@ class NumberCSVWidget(BaseCSVWidget, NumberInput):
         result = w.value_from_datadict(data, {}, "price")
         self.assertEqual(result, ["1", "2"])
 
+        data = {"price": ["1", "2"]}
+        result = w.value_from_datadict(data, {}, "price")
+        self.assertEqual(result, ["1", "2"])
+
         data = {"price": "1,,2"}
         result = w.value_from_datadict(data, {}, "price")
         self.assertEqual(result, ["1", "", "2"])