Add type hints to fields module

app/forms/field_handlers/address_handler.py

@@ -1,6 +1,7 @@
 from functools import cached_property
 
 from wtforms import FormField
+from wtforms.fields.core import UnboundField
 from wtforms.validators import InputRequired
 
 from app.forms.address_form import AddressValidatorTypes, get_address_form
@@ -28,7 +29,7 @@ def validators(self) -> AddressValidatorTypes:
 
         return validate_with
 
-    def get_field(self) -> FormField:
+    def get_field(self) -> UnboundField | FormField:
         return FormField(
             get_address_form(self.validators),
             label=self.label,

app/forms/field_handlers/date_handlers.py

@@ -1,8 +1,9 @@
 from datetime import datetime, timezone
 from functools import cached_property
-from typing import Any, Optional, Union
+from typing import Any, Optional
 
 from dateutil.relativedelta import relativedelta
+from wtforms.fields.core import UnboundField
 
 from app.forms.field_handlers.field_handler import FieldHandler
 from app.forms.fields import DateField, MonthYearDateField, YearDateField
@@ -14,10 +15,7 @@
     format_message_with_title,
 )
 from app.questionnaire.rules.utils import parse_datetime
-
-DateValidatorTypes = list[
-    Union[OptionalForm, DateRequired, DateCheck, SingleDatePeriodCheck]
-]
+from app.utilities.types import DateValidatorType
 
 
 class DateHandler(FieldHandler):
@@ -26,8 +24,8 @@ class DateHandler(FieldHandler):
     DISPLAY_FORMAT = "d MMMM yyyy"
 
     @cached_property
-    def validators(self) -> DateValidatorTypes:
-        validate_with: DateValidatorTypes = [OptionalForm()]
+    def validators(self) -> list[DateValidatorType]:
+        validate_with: list[DateValidatorType] = [OptionalForm()]
 
         if self.answer_schema["mandatory"] is True:
             validate_with = [
@@ -52,8 +50,10 @@ def validators(self) -> DateValidatorTypes:
             validate_with.append(min_max_validator)
         return validate_with
 
-    def get_field(self) -> DateField:
-        return DateField(self.validators, label=self.label, description=self.guidance)
+    def get_field(self) -> UnboundField | DateField:
+        return DateField(
+            validators=self.validators, label=self.label, description=self.guidance
+        )
 
     def get_min_max_validator(
         self, minimum_date: Optional[datetime], maximum_date: Optional[datetime]
@@ -123,9 +123,9 @@ class MonthYearDateHandler(DateHandler):
     DATE_FORMAT = "yyyy-mm"
     DISPLAY_FORMAT = "MMMM yyyy"
 
-    def get_field(self) -> MonthYearDateField:
+    def get_field(self) -> UnboundField | MonthYearDateField:
         return MonthYearDateField(
-            self.validators, label=self.label, description=self.guidance
+            validators=self.validators, label=self.label, description=self.guidance
         )
 
     def get_min_max_validator(
@@ -152,9 +152,9 @@ class YearDateHandler(DateHandler):
     DATE_FORMAT = "yyyy"
     DISPLAY_FORMAT = "yyyy"
 
-    def get_field(self) -> YearDateField:
+    def get_field(self) -> UnboundField | YearDateField:
         return YearDateField(
-            self.validators, label=self.label, description=self.guidance
+            validators=self.validators, label=self.label, description=self.guidance
         )
 
     def get_min_max_validator(

app/forms/field_handlers/dropdown_handler.py

@@ -2,13 +2,11 @@
 
 from flask_babel import lazy_gettext
 from wtforms import SelectField
+from wtforms.fields.core import UnboundField
 
-from app.forms.field_handlers.select_handlers import (
-    Choice,
-    ChoiceWithDetailAnswer,
-    SelectHandlerBase,
-)
+from app.forms.field_handlers.select_handlers import SelectHandlerBase
 from app.questionnaire.questionnaire_schema import InvalidSchemaConfigurationException
+from app.utilities.types import Choice, ChoiceWithDetailAnswer
 
 
 class DropdownHandler(SelectHandlerBase):
@@ -31,7 +29,7 @@ def choices(self) -> Sequence[Choice]:
     def _get_placeholder_text(self) -> str:
         return self.answer_schema.get("placeholder", self.DEFAULT_PLACEHOLDER)
 
-    def get_field(self) -> SelectField:
+    def get_field(self) -> UnboundField | SelectField:
         return SelectField(
             label=self.label,
             description=self.guidance,

app/forms/field_handlers/duration_handler.py

@@ -1,4 +1,5 @@
 from wtforms import FormField
+from wtforms.fields.core import UnboundField
 
 from app.forms.duration_form import get_duration_form
 from app.forms.field_handlers.field_handler import FieldHandler
@@ -7,7 +8,7 @@
 class DurationHandler(FieldHandler):
     MANDATORY_MESSAGE_KEY = "MANDATORY_DURATION"
 
-    def get_field(self) -> FormField:
+    def get_field(self) -> UnboundField | FormField:
         return FormField(
             get_duration_form(self.answer_schema, dict(self.error_messages)),
             label=self.label,

app/forms/field_handlers/mobile_number_handler.py

@@ -2,6 +2,7 @@
 from typing import Union
 
 from wtforms import StringField
+from wtforms.fields.core import UnboundField
 
 from app.forms.field_handlers.field_handler import FieldHandler
 from app.forms.validators import MobileNumberCheck, ResponseRequired
@@ -21,7 +22,7 @@ def validators(self) -> MobileNumberValidatorTypes:
 
         return validate_with
 
-    def get_field(self) -> StringField:
+    def get_field(self) -> UnboundField | StringField:
         return StringField(
             label=self.label, description=self.guidance, validators=self.validators
         )

app/forms/field_handlers/number_handler.py

@@ -2,6 +2,7 @@
 from typing import Any, Type, Union
 
 from wtforms import DecimalField, IntegerField
+from wtforms.fields.core import UnboundField
 
 from app.forms.field_handlers.field_handler import FieldHandler
 from app.forms.fields import DecimalFieldWithSeparator, IntegerFieldWithSeparator
@@ -64,7 +65,7 @@ def _field_type(
             else IntegerFieldWithSeparator
         )
 
-    def get_field(self) -> Union[DecimalField, IntegerField]:
+    def get_field(self) -> UnboundField | DecimalField | IntegerField:
         additional_args = (
             {"places": self.max_decimals}
             if self._field_type == DecimalFieldWithSeparator

app/forms/field_handlers/select_handlers.py

@@ -1,5 +1,6 @@
-from collections import namedtuple
-from typing import Any, Optional, Sequence, Union
+from typing import Any, Optional, Sequence
+
+from wtforms.fields.core import UnboundField
 
 from app.forms.field_handlers.field_handler import FieldHandler
 from app.forms.fields import (
@@ -8,13 +9,7 @@
 )
 from app.questionnaire.dynamic_answer_options import DynamicAnswerOptions
 from app.questionnaire.questionnaire_schema import InvalidSchemaConfigurationException
-
-Choice = namedtuple("Choice", "value label")
-ChoiceWithDetailAnswer = namedtuple(
-    "ChoiceWithDetailAnswer", "value label detail_answer_id"
-)
-
-ChoiceType = Union[Choice, ChoiceWithDetailAnswer]
+from app.utilities.types import ChoiceType, ChoiceWithDetailAnswer
 
 
 class SelectHandlerBase(FieldHandler):
@@ -75,7 +70,7 @@ def coerce_str_unless_none(value: Optional[str]) -> Optional[str]:
     # not providing an answer and them selecting the 'None' option otherwise.
     # https://github.com/ONSdigital/eq-survey-runner/issues/1013
     # See related WTForms PR: https://github.com/wtforms/wtforms/pull/288
-    def get_field(self) -> SelectFieldWithDetailAnswer:
+    def get_field(self) -> UnboundField | SelectFieldWithDetailAnswer:
         return SelectFieldWithDetailAnswer(
             label=self.label,
             description=self.guidance,
@@ -88,7 +83,7 @@ def get_field(self) -> SelectFieldWithDetailAnswer:
 class SelectMultipleHandler(SelectHandler):
     MANDATORY_MESSAGE_KEY = "MANDATORY_CHECKBOX"
 
-    def get_field(self) -> MultipleSelectFieldWithDetailAnswer:
+    def get_field(self) -> UnboundField | MultipleSelectFieldWithDetailAnswer:
         return MultipleSelectFieldWithDetailAnswer(
             label=self.label,
             description=self.guidance,

app/forms/field_handlers/string_handler.py

@@ -2,6 +2,7 @@
 from typing import Union
 
 from wtforms import StringField, validators
+from wtforms.fields.core import UnboundField
 from wtforms.validators import Length
 
 from app.forms.field_handlers.field_handler import FieldHandler
@@ -33,7 +34,7 @@ def max_length(self) -> int:
         max_length: int = self.answer_schema.get("max_length", self.MAX_LENGTH)
         return max_length
 
-    def get_field(self) -> StringField:
+    def get_field(self) -> UnboundField | StringField:
         return StringField(
             label=self.label, description=self.guidance, validators=self.validators
         )

app/forms/field_handlers/text_area_handler.py

@@ -2,6 +2,7 @@
 from typing import Union
 
 from wtforms import validators
+from wtforms.fields.core import UnboundField
 from wtforms.validators import Length
 
 from app.forms.field_handlers.field_handler import FieldHandler
@@ -32,7 +33,7 @@ def get_length_validator(self) -> Length:
 
         return validators.length(-1, self.max_length, message=length_message)
 
-    def get_field(self) -> MaxTextAreaField:
+    def get_field(self) -> UnboundField | MaxTextAreaField:
         return MaxTextAreaField(
             label=self.label,
             description=self.guidance,

app/forms/fields/date_field.py

@@ -1,13 +1,17 @@
 import logging
 from functools import cached_property
+from typing import Any, Callable, Sequence, Type
 
+from werkzeug.datastructures import MultiDict
 from wtforms import Form, FormField, StringField
-from wtforms.utils import unset_value
+from wtforms.utils import UnsetValue, unset_value
+
+from app.utilities.types import DateValidatorType
 
 logger = logging.getLogger(__name__)
 
 
-def get_form_class(validators):
+def get_form_class(validators: Sequence[DateValidatorType]) -> Type[Form]:
     class DateForm(Form):
         # Validation is only ever added to the 1 field that shows in all 3 variants
         # This is to prevent an error message for each input box
@@ -16,7 +20,7 @@ class DateForm(Form):
         day = StringField()
 
         @cached_property
-        def data(self):
+        def data(self) -> str | None:
             # pylint: disable=no-member
             # wtforms Form parents are not discoverable in the 2.3.3 implementation
             data = super().data
@@ -30,11 +34,24 @@ def data(self):
 
 
 class DateField(FormField):
-    def __init__(self, validators, **kwargs):
+    def __init__(
+        self,
+        *,
+        validators: Sequence[DateValidatorType],
+        **kwargs: Any,
+    ) -> None:
         form_class = get_form_class(validators)
-        super().__init__(form_class, **kwargs)
-
-    def process(self, formdata, data=unset_value, extra_filters=None):
+        super().__init__(
+            form_class,
+            **kwargs,
+        )
+
+    def process(
+        self,
+        formdata: MultiDict | None = None,
+        data: str | UnsetValue = unset_value,
+        extra_filters: Sequence[Callable] | None = None,
+    ) -> None:
         if data is not unset_value:
             substrings = data.split("-")
             data = {"year": substrings[0], "month": substrings[1], "day": substrings[2]}

app/forms/fields/decimal_field_with_separator.py

@@ -1,4 +1,5 @@
 from decimal import Decimal, InvalidOperation
+from typing import Any, Sequence
 
 from wtforms import DecimalField
 
@@ -15,11 +16,11 @@ class DecimalFieldWithSeparator(DecimalField):
     DecimalPlace validators
     """
 
-    def __init__(self, **kwargs):
+    def __init__(self, **kwargs: Any) -> None:
         super().__init__(**kwargs)
-        self.data = None
+        self.data: Decimal | None = None
 
-    def process_formdata(self, valuelist):
+    def process_formdata(self, valuelist: Sequence[str] | None = None) -> None:
         if valuelist:
             try:
                 self.data = Decimal(sanitise_number(valuelist[0]))

app/forms/fields/integer_field_with_separator.py

@@ -1,3 +1,5 @@
+from typing import Any, Sequence
+
 from wtforms import IntegerField
 
 from app.helpers.form_helpers import sanitise_number
@@ -13,11 +15,11 @@ class IntegerFieldWithSeparator(IntegerField):
     DecimalPlace validators
     """
 
-    def __init__(self, **kwargs):
+    def __init__(self, **kwargs: Any) -> None:
         super().__init__(**kwargs)
-        self.data = None
+        self.data: int | None = None
 
-    def process_formdata(self, valuelist):
+    def process_formdata(self, valuelist: Sequence[str] | None = None) -> None:
         if valuelist:
             try:
                 self.data = int(sanitise_number(valuelist[0]))

app/forms/fields/max_text_area_field.py

@@ -1,8 +1,16 @@
+from typing import Any
+
 from wtforms import TextAreaField
 
 
 class MaxTextAreaField(TextAreaField):
-    def __init__(self, label="", validators=None, rows=None, maxlength=None, **kwargs):
-        super().__init__(label, validators, **kwargs)
+    def __init__(
+        self,
+        *,
+        rows: int,
+        maxlength: int,
+        **kwargs: Any,
+    ) -> None:
+        super().__init__(**kwargs)
         self.rows = rows
         self.maxlength = maxlength