Amend InputRequired validator to support multi-input fields

CHANGES.rst

@@ -4,6 +4,9 @@ Version x.x.x
 -------------
 Unreleased
 
+- :class:`~validators.InputRequired` Validator interrogates data on entire
+  contents of field `raw_data`. :pr:`719`
+
 Version 3.0.0
 -------------
 

src/wtforms/validators.py

@@ -308,14 +308,17 @@ class InputRequired:
     looks at the post-coercion data.
 
     Sets the `required` attribute on widgets.
+
+    .. versionchanged:: 3.0,1
+        Validator interrogates data on entire contents of ``raw_data``.
     """
 
     def __init__(self, message=None):
         self.message = message
         self.field_flags = {"required": True}
 
     def __call__(self, form, field):
-        if field.raw_data and field.raw_data[0]:
+        if field.raw_data and any(field.raw_data):
             return
 
         if self.message is None:

tests/validators/test_input_required.py

@@ -4,13 +4,17 @@
 from wtforms.validators import StopValidation
 
 
-def test_input_required(dummy_form, dummy_field):
+@pytest.mark.parametrize(
+    "raw_data",
+    (["foobar"], ["", "foobar"]),
+)
+def test_input_required(dummy_form, dummy_field, raw_data):
     """
     it should pass if the required value is present
     """
     validator = input_required()
-    dummy_field.data = "foobar"
-    dummy_field.raw_data = ["foobar"]
+    dummy_field.data = "".join(raw_data)
+    dummy_field.raw_data = raw_data
 
     validator(dummy_form, dummy_field)
     assert validator.field_flags == {"required": True}