Fix handling of invalid values in form numerical inputs

app/forms/fields/decimal_field_with_separator.py

@@ -24,7 +24,9 @@ def process_formdata(self, valuelist):
         if valuelist:
             try:
                 self.data = Decimal(
-                    valuelist[0].replace(numbers.get_group_symbol(DEFAULT_LOCALE), "")
+                    valuelist[0]
+                    .replace(numbers.get_group_symbol(DEFAULT_LOCALE), "")
+                    .replace("_", "")
                 )
             except (ValueError, TypeError, InvalidOperation):
                 pass

app/forms/fields/integer_field_with_separator.py

@@ -22,7 +22,9 @@ def process_formdata(self, valuelist):
         if valuelist:
             try:
                 self.data = int(
-                    valuelist[0].replace(numbers.get_group_symbol(DEFAULT_LOCALE), "")
+                    valuelist[0]
+                    .replace(numbers.get_group_symbol(DEFAULT_LOCALE), "")
+                    .replace("_", "")
                 )
             except ValueError:
                 pass

app/forms/validators.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import math
 import re
 from datetime import datetime, timezone
 from decimal import Decimal, InvalidOperation
@@ -48,11 +49,17 @@ def __call__(
         form: FlaskForm,
         field: Union[DecimalFieldWithSeparator, IntegerFieldWithSeparator],
     ) -> None:
+        try:
+            if math.isnan(float(field.raw_data[0])):
+                raise validators.StopValidation(self.message)
+        except (TypeError, ValueError):
+            pass
+
         try:
             Decimal(
-                field.raw_data[0].replace(
-                    numbers.get_group_symbol(flask_babel.get_locale()), ""
-                )
+                field.raw_data[0]
+                .replace(numbers.get_group_symbol(flask_babel.get_locale()), "")
+                .replace("_", "")
             )
         except (ValueError, TypeError, InvalidOperation, AttributeError) as exc:
             raise validators.StopValidation(self.message) from exc
@@ -126,6 +133,14 @@ def __call__(
         field: Union[DecimalFieldWithSeparator, IntegerFieldWithSeparator],
     ) -> None:
         value: Union[int, Decimal] = field.data
+        try:
+            raw_value = float(field.raw_data[0])
+        except (TypeError, ValueError):
+            raw_value = False
+
+        if math.isnan(raw_value):
+            raise validators.ValidationError(self.messages["INVALID_NUMBER"])
+
         if value is not None:
             error_message = self.validate_minimum(value) or self.validate_maximum(value)
             if error_message:
@@ -183,6 +198,7 @@ def __call__(
             field.raw_data[0]
             .replace(numbers.get_group_symbol(flask_babel.get_locale()), "")
             .replace(" ", "")
+            .replace("_", "")
         )
         decimal_symbol = numbers.get_decimal_symbol(flask_babel.get_locale())
         if data and decimal_symbol in data:

tests/app/forms/test_custom_fields.py

@@ -1,3 +1,5 @@
+from decimal import Decimal
+
 import pytest
 from wtforms.fields import Field
 
@@ -31,6 +33,41 @@ def test_integer_field(mock_form):
         pytest.fail("Exceptions should not thrown by CustomIntegerField")
 
 
+@pytest.mark.parametrize(
+    "number_input, result",
+    [
+        ("_110", 110),
+        ("1_10", 110),
+        ("1__10", 110),
+        ("1_1,0", 110),
+        ("_1_1,0,0", 1100),
+        ("1.10", None),
+    ],
+)
+def test_integer_field_inputs(mock_form, number_input, result):
+    integer_field = IntegerFieldWithSeparator(_form=mock_form, name="aName")
+    integer_field.process_formdata([number_input])
+
+    assert integer_field.data == result
+
+
+@pytest.mark.parametrize(
+    "number_input, result",
+    [
+        ("1_1,0", Decimal("110")),
+        ("1.10", Decimal("1.1")),
+        ("_1.1_0", Decimal("1.1")),
+        ("_1.1_0,0", Decimal("1.1")),
+        ("_1._1,0,0", Decimal("1.1")),
+    ],
+)
+def test_decimal_field_inputs(mock_form, number_input, result):
+    decimal_field = DecimalFieldWithSeparator(_form=mock_form, name="aName")
+    decimal_field.process_formdata([number_input])
+
+    assert decimal_field.data == result
+
+
 def test_decimal_field(mock_form):
     decimal_field = DecimalFieldWithSeparator(_form=mock_form, name="aName")
     assert isinstance(decimal_field, Field)

tests/app/forms/validation/test_number_range_validator.py

@@ -27,6 +27,15 @@
             "NUMBER_TOO_SMALL_EXCLUSIVE",
             {"min": "10"},
         ),
+        (
+            10,
+            100,
+            "NaN",
+            False,
+            True,
+            "INVALID_NUMBER",
+            {"max": "100"},
+        ),
         (
             None,
             1000,
@@ -57,13 +66,45 @@ def test_number_range_validator_raises_ValidationError(
         maximum_exclusive=max_excl,
     )
     mock_field.data = value
+    mock_field.raw_data = [value]
 
     with pytest.raises(ValidationError) as exc:
         validator(mock_form, mock_field)
 
     assert error_messages[error_type] % error_dict == str(exc.value)
 
 
+@pytest.mark.usefixtures("gb_locale")
+def test_number_range_validator_nan_check_passes(mock_form, mock_field, value=None):
+    validator = NumberRange(
+        minimum=10,
+        maximum=100,
+        minimum_exclusive=False,
+        maximum_exclusive=False,
+    )
+    mock_field.data = value
+    mock_field.raw_data = [value]
+
+    validator(mock_form, mock_field)
+
+
+@pytest.mark.usefixtures("gb_locale")
+def test_number_range_validator_nan_check_raises_exception(
+    mock_form, mock_field, value="NaN"
+):
+    validator = NumberRange(
+        minimum=10,
+        maximum=100,
+        minimum_exclusive=False,
+        maximum_exclusive=False,
+    )
+    mock_field.data = value
+    mock_field.raw_data = [value]
+
+    with pytest.raises(ValidationError):
+        validator(mock_form, mock_field)
+
+
 @pytest.mark.parametrize(
     "minimum, maximum, value",
     (
@@ -76,5 +117,6 @@ def test_number_range_validator_raises_ValidationError(
 def test_number_range_validator(minimum, maximum, value, mock_form, mock_field):
     validator = NumberRange(minimum=minimum, maximum=maximum)
     mock_field.data = value
+    mock_field.raw_data = [value]
 
     validator(mock_form, mock_field)

tests/app/forms/validation/test_number_validator.py

@@ -7,12 +7,7 @@
 
 @pytest.mark.parametrize(
     "value",
-    (
-        [None],
-        [""],
-        ["a"],
-        ["2E2"],
-    ),
+    ([None], [""], ["a"], ["2E2"], ["NaN"]),
 )
 @pytest.mark.usefixtures("gb_locale")
 def test_number_validator_raises_StopValidation(