chore(models): remove null=True from TextFields

change default to empty string

these are stored as the empty string when blank=True
Django recommends against null=True on TextFields: https://docs.djangoproject.com/en/5.1/ref/models/fields/#null

benefits/core/migrations/0032_optionalfields.py

@@ -202,61 +202,105 @@ class Migration(migrations.Migration):
             old_name="selection_label_template",
             new_name="selection_label_template_override",
         ),
-        migrations.AlterField(
-            model_name="enrollmentflow",
-            name="system_name",
-            field=models.SlugField(
-                help_text="Primary internal system name for this EnrollmentFlow instance, e.g. in analytics and Eligibility API requests.",  # noqa: E501
-            ),
-        ),
         migrations.AlterField(
             model_name="enrollmentflow",
             name="selection_label_template_override",
             field=models.TextField(
                 blank=True,
-                default=None,
+                default="",
                 help_text="Override the default template that defines the end-user UI for selecting this flow among other options.",  # noqa: E501
-                null=True,
             ),
         ),
         migrations.AlterField(
             model_name="enrollmentflow",
             name="eligibility_start_template_override",
             field=models.TextField(
                 blank=True,
-                default=None,
+                default="",
                 help_text="Override the default template for the informational page of this flow.",
-                null=True,
             ),
         ),
         migrations.AlterField(
             model_name="enrollmentflow",
             name="eligibility_unverified_template_override",
             field=models.TextField(
                 blank=True,
-                default=None,
+                default="",
                 help_text="Override the default template that defines the page when a user fails eligibility verification for this flow.",  # noqa: E501
-                null=True,
             ),
         ),
         migrations.AlterField(
             model_name="enrollmentflow",
             name="enrollment_index_template_override",
             field=models.TextField(
                 blank=True,
-                default=None,
+                default="",
                 help_text="Override the default template for the Eligibility Confirmation page (the index of the enrollment app)",  # noqa: E501
-                null=True,
             ),
         ),
         migrations.AlterField(
             model_name="enrollmentflow",
             name="enrollment_success_template_override",
             field=models.TextField(
                 blank=True,
-                default=None,
+                default="",
                 help_text="Override the default template for a successful enrollment associated with the enrollment flow",
-                null=True,
+            ),
+        ),
+        migrations.AlterField(
+            model_name="enrollmentflow",
+            name="reenrollment_error_template",
+            field=models.TextField(
+                blank=True, default="", help_text="Template for a re-enrollment error associated with the enrollment flow"
+            ),
+        ),
+        migrations.AlterField(
+            model_name="enrollmentflow",
+            name="help_template",
+            field=models.TextField(
+                blank=True,
+                default="",
+                help_text="Path to a Django template that defines the help text for this enrollment flow, used in building the dynamic help page for an agency",  # noqa: E501
+            ),
+        ),
+        migrations.AlterField(
+            model_name="enrollmentflow",
+            name="claims_scheme_override",
+            field=models.TextField(
+                blank=True,
+                default="",
+                help_text="The authentication scheme to use (Optional). If blank, defaults to the value in Claims providers",
+                verbose_name="Claims scheme",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="enrollmentflow",
+            name="system_name",
+            field=models.SlugField(
+                help_text="Primary internal system name for this EnrollmentFlow instance, e.g. in analytics and Eligibility API requests.",  # noqa: E501
+            ),
+        ),
+        migrations.AlterField(
+            model_name="enrollmentflow",
+            name="eligibility_form_class",
+            field=models.TextField(
+                blank=True,
+                default="",
+                help_text="The fully qualified Python path of a form class used by this flow, e.g. benefits.eligibility.forms.FormClass",  # noqa: E501
+            ),
+        ),
+        migrations.AlterField(
+            model_name="enrollmentflow",
+            name="group_id",
+            field=models.TextField(
+                blank=True, default="", help_text="Reference to the TransitProcessor group for user enrollment"
+            ),
+        ),
+        migrations.AlterField(
+            model_name="enrollmentflow",
+            name="label",
+            field=models.TextField(
+                blank=True, default="", help_text="A human readable label, used as the display text in Admin."
             ),
         ),
     ]

benefits/core/models.py

@@ -401,8 +401,7 @@ class EnrollmentFlow(models.Model):
     claims_extra_claims = models.TextField(null=True, blank=True, help_text="A space-separated list of any additional claims")
     claims_scheme_override = models.TextField(
         help_text="The authentication scheme to use (Optional). If blank, defaults to the value in Claims providers",
-        default=None,
-        null=True,
+        default="",
         blank=True,
         verbose_name="Claims scheme",
     )
@@ -443,38 +442,38 @@ class EnrollmentFlow(models.Model):
         help_text="The JWS-compatible signing algorithm to use in Eligibility API requests for this flow.",
     )
     selection_label_template_override = models.TextField(
-        null=True,
         blank=True,
-        default=None,
+        default="",
         help_text="Override the default template that defines the end-user UI for selecting this flow among other options.",
     )
     eligibility_start_template_override = models.TextField(
-        null=True,
         blank=True,
-        default=None,
+        default="",
         help_text="Override the default template for the informational page of this flow.",
     )
     eligibility_form_class = models.TextField(
-        null=True,
         blank=True,
+        default="",
         help_text="The fully qualified Python path of a form class used by this flow, e.g. benefits.eligibility.forms.FormClass",  # noqa: E501
     )
     eligibility_unverified_template_override = models.TextField(
-        help_text="Override the default template that defines the page when a user fails eligibility verification for this flow.",  # noqa: E501
         blank=True,
-        null=True,
-        default=None,
+        default="",
+        help_text="Override the default template that defines the page when a user fails eligibility verification for this flow.",  # noqa: E501
     )
     help_template = models.TextField(
-        null=True,
         blank=True,
+        default="",
         help_text="Path to a Django template that defines the help text for this enrollment flow, used in building the dynamic help page for an agency",  # noqa: E501
     )
     label = models.TextField(
-        null=True,
+        blank=True,
+        default="",
         help_text="A human readable label, used as the display text in Admin.",
     )
-    group_id = models.TextField(null=True, help_text="Reference to the TransitProcessor group for user enrollment")
+    group_id = models.TextField(
+        blank=True, default="", help_text="Reference to the TransitProcessor group for user enrollment"
+    )
     supports_expiration = models.BooleanField(
         default=False, help_text="Indicates if the enrollment expires or does not expire"
     )
@@ -487,18 +486,16 @@ class EnrollmentFlow(models.Model):
         help_text="If the enrollment supports expiration, number of days preceding the expiration date during which a user can re-enroll in the eligibilty",  # noqa: E501
     )
     enrollment_index_template_override = models.TextField(
-        help_text="Override the default template for the Eligibility Confirmation page (the index of the enrollment app)",
-        null=True,
         blank=True,
-        default=None,
+        default="",
+        help_text="Override the default template for the Eligibility Confirmation page (the index of the enrollment app)",
     )
     reenrollment_error_template = models.TextField(
-        null=True, blank=True, help_text="Template for a re-enrollment error associated with the enrollment flow"
+        blank=True, default="", help_text="Template for a re-enrollment error associated with the enrollment flow"
     )
     enrollment_success_template_override = models.TextField(
-        null=True,
         blank=True,
-        default=None,
+        default="",
         help_text="Override the default template for a successful enrollment associated with the enrollment flow",
     )
     supported_enrollment_methods = MultiSelectField(

benefits/enrollment/views.py

@@ -143,7 +143,7 @@ def reenrollment_error(request):
     """View handler for a re-enrollment attempt that is not yet within the re-enrollment window."""
     flow = session.flow(request)
 
-    if flow.reenrollment_error_template is None:
+    if not flow.reenrollment_error_template:
         raise Exception(f"Re-enrollment error with null template on: {flow}")
 
     if session.logged_in(request) and flow.claims_provider.supports_sign_out:

tests/pytest/core/test_models.py

@@ -323,11 +323,11 @@ def test_EnrollmentFlow_template_overrides_claims(model_EnrollmentFlow_with_scop
         == model_EnrollmentFlow_with_scope_and_claim.enrollment_success_template_override
     )
 
-    model_EnrollmentFlow_with_scope_and_claim.selection_label_template_override = None
-    model_EnrollmentFlow_with_scope_and_claim.eligibility_start_template_override = None
-    model_EnrollmentFlow_with_scope_and_claim.eligibility_unverified_template_override = None
-    model_EnrollmentFlow_with_scope_and_claim.enrollment_index_template_override = None
-    model_EnrollmentFlow_with_scope_and_claim.enrollment_success_template_override = None
+    model_EnrollmentFlow_with_scope_and_claim.selection_label_template_override = ""
+    model_EnrollmentFlow_with_scope_and_claim.eligibility_start_template_override = ""
+    model_EnrollmentFlow_with_scope_and_claim.eligibility_unverified_template_override = ""
+    model_EnrollmentFlow_with_scope_and_claim.enrollment_index_template_override = ""
+    model_EnrollmentFlow_with_scope_and_claim.enrollment_success_template_override = ""
     model_EnrollmentFlow_with_scope_and_claim.save()
 
     assert (
@@ -348,11 +348,11 @@ def test_EnrollmentFlow_template_overrides_claims(model_EnrollmentFlow_with_scop
 
 @pytest.mark.django_db
 def test_EnrollmentFlow_template_overrides_eligibility_api(model_EnrollmentFlow_with_eligibility_api):
-    model_EnrollmentFlow_with_eligibility_api.selection_label_template_override = None
-    model_EnrollmentFlow_with_eligibility_api.eligibility_start_template_override = None
-    model_EnrollmentFlow_with_eligibility_api.eligibility_unverified_template_override = None
-    model_EnrollmentFlow_with_eligibility_api.enrollment_index_template_override = None
-    model_EnrollmentFlow_with_eligibility_api.enrollment_success_template_override = None
+    model_EnrollmentFlow_with_eligibility_api.selection_label_template_override = ""
+    model_EnrollmentFlow_with_eligibility_api.eligibility_start_template_override = ""
+    model_EnrollmentFlow_with_eligibility_api.eligibility_unverified_template_override = ""
+    model_EnrollmentFlow_with_eligibility_api.enrollment_index_template_override = ""
+    model_EnrollmentFlow_with_eligibility_api.enrollment_success_template_override = ""
     model_EnrollmentFlow_with_eligibility_api.save()
 
     assert (