💥 [#3283] Removing registration_backend from form

The deprecated fields `registration_backend` and `registration_backend_options` have been removed. The field `registration_backends` should now be used in all situations.

These fields have also been removed from the import and export. This means, when you import a form using the `registration_backend` config, the registration will no longer be converted to `registration_backends`.

docs/installation/upgrade-300.rst

@@ -74,3 +74,10 @@ StUF-ZDS payments extension conversion
 The import conversion of StUF-ZDS plugin extensions, back to the default StUF-ZDS plugin,
 has been removed. We recommend re-creating the exports on a newer version of Open Forms,
 or manually changing the plugin to `stuf-zds-create-zaak` in the export files.
+
+Removal of single registration conversion
+-----------------------------------------
+
+The legacy format (from before Open Forms 2.3) for registration backend will no longer be
+converted to the current standard. When importing a form with this configuration,
+the form will be created without registration backends.

src/openapi.yaml

@@ -1325,8 +1325,6 @@ paths:
 
         - `internalName`
         - `registrationBackends`
-        - `registrationBackend`
-        - `registrationBackendOptions`
         - `authenticationBackendOptions`
         - `paymentBackend`
         - `paymentBackendOptions`
@@ -1399,8 +1397,6 @@ paths:
 
         - `internalName`
         - `registrationBackends`
-        - `registrationBackend`
-        - `registrationBackendOptions`
         - `authenticationBackendOptions`
         - `paymentBackend`
         - `paymentBackendOptions`
@@ -1917,8 +1913,6 @@ paths:
 
         - `internalName`
         - `registrationBackends`
-        - `registrationBackend`
-        - `registrationBackendOptions`
         - `authenticationBackendOptions`
         - `paymentBackend`
         - `paymentBackendOptions`
@@ -1997,8 +1991,6 @@ paths:
 
         - `internalName`
         - `registrationBackends`
-        - `registrationBackend`
-        - `registrationBackendOptions`
         - `authenticationBackendOptions`
         - `paymentBackend`
         - `paymentBackendOptions`
@@ -2081,8 +2073,6 @@ paths:
 
         - `internalName`
         - `registrationBackends`
-        - `registrationBackend`
-        - `registrationBackendOptions`
         - `authenticationBackendOptions`
         - `paymentBackend`
         - `paymentBackendOptions`
@@ -7564,7 +7554,7 @@ components:
 
         Note that this schema is used for both non-admin users filling out forms and
         admin users designing forms. The fields that are only relevant for admin users are:
-        `internalName`, `registrationBackends`, `registrationBackend`, `registrationBackendOptions`, `authenticationBackendOptions`, `paymentBackend`, `paymentBackendOptions`, `priceVariableKey`, `product`, `category`, `theme`, `activateOn`, `deactivateOn`, `isDeleted`, `submissionConfirmationTemplate`, `askPrivacyConsent`, `askStatementOfTruth`, `submissionsRemovalOptions`, `confirmationEmailTemplate`, `sendConfirmationEmail`, `displayMainWebsiteLink`, `includeConfirmationPageContentInPdf`, `translations`, `brpPersonenRequestOptions`.
+        `internalName`, `registrationBackends`, `authenticationBackendOptions`, `paymentBackend`, `paymentBackendOptions`, `priceVariableKey`, `product`, `category`, `theme`, `activateOn`, `deactivateOn`, `isDeleted`, `submissionConfirmationTemplate`, `askPrivacyConsent`, `askStatementOfTruth`, `submissionsRemovalOptions`, `confirmationEmailTemplate`, `sendConfirmationEmail`, `displayMainWebsiteLink`, `includeConfirmationPageContentInPdf`, `translations`, `brpPersonenRequestOptions`.
       properties:
         uuid:
           type: string
@@ -7586,12 +7576,6 @@ components:
           type: array
           items:
             $ref: '#/components/schemas/FormRegistrationBackend'
-        registrationBackend:
-          type: string
-          deprecated: true
-        registrationBackendOptions:
-          nullable: true
-          deprecated: true
         authenticationBackends:
           type: array
           items:
@@ -8077,7 +8061,7 @@ components:
 
         Note that this schema is used for both non-admin users filling out forms and
         admin users designing forms. The fields that are only relevant for admin users are:
-        `internalName`, `registrationBackends`, `registrationBackend`, `registrationBackendOptions`, `authenticationBackendOptions`, `paymentBackend`, `paymentBackendOptions`, `priceVariableKey`, `product`, `category`, `theme`, `activateOn`, `deactivateOn`, `isDeleted`, `submissionConfirmationTemplate`, `askPrivacyConsent`, `askStatementOfTruth`, `submissionsRemovalOptions`, `confirmationEmailTemplate`, `sendConfirmationEmail`, `displayMainWebsiteLink`, `includeConfirmationPageContentInPdf`, `translations`, `brpPersonenRequestOptions`.
+        `internalName`, `registrationBackends`, `authenticationBackendOptions`, `paymentBackend`, `paymentBackendOptions`, `priceVariableKey`, `product`, `category`, `theme`, `activateOn`, `deactivateOn`, `isDeleted`, `submissionConfirmationTemplate`, `askPrivacyConsent`, `askStatementOfTruth`, `submissionsRemovalOptions`, `confirmationEmailTemplate`, `sendConfirmationEmail`, `displayMainWebsiteLink`, `includeConfirmationPageContentInPdf`, `translations`, `brpPersonenRequestOptions`.
       properties:
         name:
           type: string
@@ -8248,7 +8232,7 @@ components:
 
         Note that this schema is used for both non-admin users filling out forms and
         admin users designing forms. The fields that are only relevant for admin users are:
-        `internalName`, `registrationBackends`, `registrationBackend`, `registrationBackendOptions`, `authenticationBackendOptions`, `paymentBackend`, `paymentBackendOptions`, `priceVariableKey`, `product`, `category`, `theme`, `activateOn`, `deactivateOn`, `isDeleted`, `submissionConfirmationTemplate`, `askPrivacyConsent`, `askStatementOfTruth`, `submissionsRemovalOptions`, `confirmationEmailTemplate`, `sendConfirmationEmail`, `displayMainWebsiteLink`, `includeConfirmationPageContentInPdf`, `translations`, `brpPersonenRequestOptions`.
+        `internalName`, `registrationBackends`, `authenticationBackendOptions`, `paymentBackend`, `paymentBackendOptions`, `priceVariableKey`, `product`, `category`, `theme`, `activateOn`, `deactivateOn`, `isDeleted`, `submissionConfirmationTemplate`, `askPrivacyConsent`, `askStatementOfTruth`, `submissionsRemovalOptions`, `confirmationEmailTemplate`, `sendConfirmationEmail`, `displayMainWebsiteLink`, `includeConfirmationPageContentInPdf`, `translations`, `brpPersonenRequestOptions`.
       properties:
         name:
           type: string
@@ -9182,7 +9166,7 @@ components:
 
         Note that this schema is used for both non-admin users filling out forms and
         admin users designing forms. The fields that are only relevant for admin users are:
-        `internalName`, `registrationBackends`, `registrationBackend`, `registrationBackendOptions`, `authenticationBackendOptions`, `paymentBackend`, `paymentBackendOptions`, `priceVariableKey`, `product`, `category`, `theme`, `activateOn`, `deactivateOn`, `isDeleted`, `submissionConfirmationTemplate`, `askPrivacyConsent`, `askStatementOfTruth`, `submissionsRemovalOptions`, `confirmationEmailTemplate`, `sendConfirmationEmail`, `displayMainWebsiteLink`, `includeConfirmationPageContentInPdf`, `translations`, `brpPersonenRequestOptions`.
+        `internalName`, `registrationBackends`, `authenticationBackendOptions`, `paymentBackend`, `paymentBackendOptions`, `priceVariableKey`, `product`, `category`, `theme`, `activateOn`, `deactivateOn`, `isDeleted`, `submissionConfirmationTemplate`, `askPrivacyConsent`, `askStatementOfTruth`, `submissionsRemovalOptions`, `confirmationEmailTemplate`, `sendConfirmationEmail`, `displayMainWebsiteLink`, `includeConfirmationPageContentInPdf`, `translations`, `brpPersonenRequestOptions`.
       properties:
         uuid:
           type: string
@@ -9204,12 +9188,6 @@ components:
           type: array
           items:
             $ref: '#/components/schemas/FormRegistrationBackend'
-        registrationBackend:
-          type: string
-          deprecated: true
-        registrationBackendOptions:
-          nullable: true
-          deprecated: true
         authenticationBackends:
           type: array
           items:

src/openforms/fixtures/demo.json

@@ -7,8 +7,7 @@
         "name": "\u2615\ufe0f",
         "slug": "koffie",
         "active": true,
-        "product": null,
-        "registration_backend": "openforms.core.backends.console_backend"
+        "product": null
     }
 },
 {
@@ -19,8 +18,18 @@
         "name": "Demo multiple steps",
         "slug": "demo-multiple-steps",
         "active": true,
-        "product": null,
-        "registration_backend": ""
+        "product": null
+    }
+},
+{
+    "model": "forms.form_formregistrationbackend",
+    "pk": 1,
+    "fields": {
+        "key": "backend",
+        "name": "backend",
+        "backend": "openforms.core.backends.console_backend",
+        "options": {},
+        "form": 1
     }
 },
 {

src/openforms/forms/api/serializers/form.py

@@ -1,5 +1,3 @@
-import warnings
-
 from django.db import transaction
 from django.utils.translation import gettext_lazy as _
 
@@ -100,8 +98,6 @@ def validate(self, attrs):
 
 @extend_schema_serializer(
     deprecate_fields=[
-        "registration_backend",
-        "registration_backend_options",
         "cosign_login_info",
     ]
 )
@@ -224,12 +220,6 @@ class FormSerializer(PublicFieldsSerializerMixin, serializers.ModelSerializer):
 
     registration_backends = FormRegistrationBackendSerializer(many=True, required=False)
 
-    # deprecated fields
-    registration_backend = serializers.CharField(required=False, allow_blank=True)
-    registration_backend_options = serializers.JSONField(
-        required=False, allow_null=True
-    )
-
     class Meta:
         model = Form
         fields = (
@@ -239,8 +229,6 @@ class Meta:
             "login_required",
             "translation_enabled",
             "registration_backends",
-            "registration_backend",
-            "registration_backend_options",
             "authentication_backends",
             "authentication_backend_options",
             "login_options",
@@ -342,26 +330,6 @@ def create(self, validated_data):
         )
         registration_backends = validated_data.pop("registration_backends", [])
 
-        registration_backend_options = (
-            validated_data.pop("registration_backend_options", None) or {}
-        )
-        if "registration_backend" in validated_data:
-            warnings.warn(
-                (
-                    "Form 'registration_backend' and 'registration_backend_options' "
-                    "are deprecated, use 'registration_backends' instead."
-                ),
-                DeprecationWarning,
-            )
-            registration_backends.append(
-                {
-                    "key": "default",
-                    "name": _("Default"),
-                    "backend": validated_data.pop("registration_backend"),
-                    "options": registration_backend_options,
-                }
-            )
-
         instance = super().create(validated_data)
         ConfirmationEmailTemplate.objects.set_for_form(
             form=instance, data=confirmation_email_template
@@ -376,33 +344,6 @@ def create(self, validated_data):
         )
         return instance
 
-    def _update_v2_registration_backend(self, form, validated_data):
-        new_data = {}
-        if "registration_backend" in validated_data:
-            new_data["backend"] = validated_data.pop("registration_backend")
-        if "registration_backend_options" in validated_data:
-            new_data["options"] = validated_data.pop("registration_backend_options")
-        if not any(v is not None for v in new_data.values()):
-            return
-
-        warnings.warn(
-            (
-                "Form 'registration_backend' and 'registration_backend_options' "
-                "are deprecated, use 'registration_backends' instead."
-            ),
-            DeprecationWarning,
-        )
-
-        backend = form.registration_backends.first() or FormRegistrationBackend(
-            form=form, name=_("Default"), key="default"
-        )
-        serializer = FormRegistrationBackendSerializer(
-            instance=backend, data=new_data, context=self.context, partial=self.partial
-        )
-        # validated_data ought to be correct already
-        assert serializer.is_valid()
-        serializer.save()
-
     @transaction.atomic()
     def update(self, instance, validated_data):
         confirmation_email_template = validated_data.pop(
@@ -413,8 +354,6 @@ def update(self, instance, validated_data):
         )
         registration_backends = validated_data.pop("registration_backends", None)
 
-        self._update_v2_registration_backend(instance, validated_data)
-
         instance = super().update(instance, validated_data)
         ConfirmationEmailTemplate.objects.set_for_form(
             form=instance, data=confirmation_email_template
@@ -446,43 +385,11 @@ def get_fields(self):
                 ("", "")
             ] + payment_register.get_choices()
 
-        # adapt fields for v2 backwards compatibility
-        if "registration_backends" in fields:
-            v2_backend = fields["registration_backend"]
-            v3_backend = fields["registration_backends"].child.get_fields()["backend"]
-            v2_backend.choices = v3_backend.choices
-
         return fields
 
     def validate(self, attrs):
         super().validate(attrs)
 
-        if "registration_backend" in attrs and "registration_backends" in attrs:
-            raise serializers.ValidationError(
-                {
-                    "registration_backend": ErrorDetail(
-                        _(
-                            "registration_backend is deprecated, please use just registration_backends",
-                        ),
-                        code="invalid",
-                    ),
-                    "registration_backend_options": ErrorDetail(
-                        _(
-                            "registration_backend is deprecated, please use just registration_backends",
-                        ),
-                        code="invalid",
-                    ),
-                }
-            )
-
-        if "registration_backends" not in attrs:
-            self.validate_backend_options(
-                attrs,
-                "registration_backend",
-                "registration_backend_options",
-                registration_register,
-            )
-
         self.validate_backend_options(
             attrs, "payment_backend", "payment_backend_options", payment_register
         )
@@ -509,7 +416,7 @@ def validate_backend_options(self, attrs, backend_field, options_field, registry
         except serializers.ValidationError as e:
             # wrap detail in dict so we can attach it to the field
             # DRF will create the .invalidParams with a dotted path to nested fields
-            # like registrationBackendOptions.toEmails.0 if the first email was invalid
+            # like registrationBackends.0.options.toEmails.0 if the first email was invalid
             detail = {options_field: e.detail}
             raise serializers.ValidationError(detail) from e
         # serializer does some normalization, so make sure to update the data
@@ -623,10 +530,6 @@ def get_fields(self):
             del fields["payment_options"]
         if "authentication_backends" in fields:
             fields["authentication_backends"].write_only = False
-        if "registration_backend" in fields:
-            del fields["registration_backend"]
-        if "registration_backend_options" in fields:
-            del fields["registration_backend_options"]
         return fields
 
 

src/openforms/forms/models/form.py

@@ -394,20 +394,6 @@ def get_absolute_url(self):
     def get_api_url(self):
         return reverse("api:form-detail", kwargs={"uuid": self.uuid})
 
-    @property
-    def registration_backend(self) -> str | None:
-        "For backwards compatibility"
-        return (
-            backend.backend if (backend := self.registration_backends.first()) else None
-        )
-
-    @property
-    def registration_backend_options(self) -> str | None:
-        "For backwards compatibility"
-        return (
-            backend.options if (backend := self.registration_backends.first()) else None
-        )
-
     def get_registration_backend_display(self) -> str:
         return (
             ", ".join(