Support max_length argument for SplitPhoneNumberField

Allow using the field with `fields_for_model`, `ModelForm`, …

Author: francoisfreitag

phonenumber_field/formfields.py

@@ -105,7 +105,14 @@ class SplitPhoneNumberField(MultiValueField):
     widget = widgets.PhoneNumberPrefixWidget
 
     def __init__(
-        self, *, initial=None, region=None, widget=None, empty_value="", **kwargs
+        self,
+        *,
+        initial=None,
+        region=None,
+        widget=None,
+        empty_value="",
+        max_length=None,
+        **kwargs,
     ):
         """
         :keyword list initial: A two-elements iterable:
@@ -125,6 +132,8 @@ def __init__(
         :keyword ~django.forms.MultiWidget widget: defaults to
             :class:`~phonenumber_field.widgets.PhoneNumberPrefixWidget`
         :keyword empty_value: value to use when the field is empty
+        :keyword int max_length: maximum length of the phone number, when
+            represented as :setting:`PHONENUMBER_DB_FORMAT`.
         """
         validate_region(region)
         region = region or getattr(settings, "PHONENUMBER_DEFAULT_REGION", None)
@@ -136,6 +145,7 @@ def __init__(
         if widget is None:
             widget = self.widget((prefix_field.widget, number_field.widget))
         self.empty_value = empty_value
+        self.max_length = max_length
         super().__init__(fields, initial=initial, widget=widget, **kwargs)
 
     def prefix_field(self):
@@ -192,4 +202,19 @@ def clean(self, value):
                         error_message,
                         example_number=example_number,
                     )
-        return super().clean(value)
+        clean_value = super().clean(value)
+        if self.max_length is not None:
+            phonenumber_str = clean_value.format_as(
+                getattr(settings, "PHONENUMBER_DB_FORMAT", "E164")
+            )
+            if len(phonenumber_str) > self.max_length:
+                raise ValidationError(
+                    format_lazy(
+                        "Ensure this value has no more than {max_length} characters, "
+                        "“{value}” is {length} characters long.",
+                        max_length=self.max_length,
+                        value=phonenumber_str,
+                        length=len(phonenumber_str),
+                    )
+                )
+        return clean_value

tests/models.py

@@ -104,3 +104,7 @@ class FrenchPhoneOwner(models.Model):
 
 class TestModelRegionAR(models.Model):
     phone = PhoneNumberField(region="AR", blank=True, null=True)
+
+
+class PhoneNumberWithMaxLength(models.Model):
+    phone = PhoneNumberField(max_length=3)

tests/test_formfields.py

@@ -12,6 +12,7 @@
 from phonenumber_field.formfields import PhoneNumberField, SplitPhoneNumberField
 from phonenumber_field.phonenumber import PhoneNumber
 from phonenumber_field.validators import validate_phonenumber
+from tests.models import NullablePhoneNumber, PhoneNumberWithMaxLength
 
 ALGERIAN_PHONE_NUMBER = "+213799136332"
 
@@ -708,3 +709,39 @@ class TestForm(forms.Form):
 
         form = TestForm({"phone_0": "FR", "phone_1": "1010"})
         self.assertIs(form.is_valid(), True)
+
+    def test_formfield_with_maxlength_null(self):
+        class TestForm(forms.Form):
+            def __init__(self, *args, **kwargs):
+                super().__init__(*args, **kwargs)
+                self.fields = forms.fields_for_model(
+                    NullablePhoneNumber,
+                    ["phone_number"],
+                    field_classes={"phone_number": SplitPhoneNumberField},
+                )
+
+        form = TestForm(data={"phone_number_0": "FR", "phone_number_1": "612345678"})
+        self.assertIs(form.is_valid(), True)
+        self.assertEqual(form.cleaned_data["phone_number"], "+33612345678")
+
+    def test_formfield_with_max_length(self):
+        class TestForm(forms.Form):
+            def __init__(self, *args, **kwargs):
+                super().__init__(*args, **kwargs)
+                self.fields = forms.fields_for_model(
+                    PhoneNumberWithMaxLength,
+                    ["phone"],
+                    field_classes={"phone": SplitPhoneNumberField},
+                )
+
+        form = TestForm(data={"phone_0": "FR", "phone_1": "33612345678"})
+        self.assertIs(form.is_valid(), False)
+        self.assertEqual(
+            form.errors,
+            {
+                "phone": [
+                    "Ensure this value has no more than 3 characters, "
+                    "“6 12 34 56 78” is 13 characters long."
+                ],
+            },
+        )