Moving choices to admin form instead of models.

TNL-4296

common/djangoapps/third_party_auth/admin.py

@@ -13,14 +13,23 @@ from .models import (
     SAMLConfiguration,
     SAMLProviderData,
     LTIProviderConfig,
-    ProviderApiPermissions
+    ProviderApiPermissions,
+    _PSA_OAUTH2_BACKENDS,
+    _PSA_SAML_BACKENDS
 )
 from .tasks import fetch_saml_metadata
 from third_party_auth.provider import Registry
 
 
+class OAuth2ProviderConfigForm(forms.ModelForm):
+    """ Django Admin form class for OAuth2ProviderConfig """
+    backend_name = forms.ChoiceField(choices=((name, name) for name in _PSA_OAUTH2_BACKENDS))
+
+
 class OAuth2ProviderConfigAdmin(KeyedConfigurationModelAdmin):
     """ Django Admin class for OAuth2ProviderConfig """
+    form = OAuth2ProviderConfigForm
+
     def get_list_display(self, request):
         """ Don't show every single field in the admin change list """
         return (
@@ -31,8 +40,15 @@ class OAuth2ProviderConfigAdmin(KeyedConfigurationModelAdmin):
 admin.site.register(OAuth2ProviderConfig, OAuth2ProviderConfigAdmin)
 
 
+class SAMLProviderConfigForm(forms.ModelForm):
+    """ Django Admin form class for SAMLProviderConfig """
+    backend_name = forms.ChoiceField(choices=((name, name) for name in _PSA_SAML_BACKENDS))
+
+
 class SAMLProviderConfigAdmin(KeyedConfigurationModelAdmin):
     """ Django Admin class for SAMLProviderConfig """
+    form = SAMLProviderConfigForm
+
     def get_list_display(self, request):
         """ Don't show every single field in the admin change list """
         return (

common/djangoapps/third_party_auth/migrations/0002_auto_20160325_0407.py

@@ -1,24 +0,0 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
-from django.db import migrations, models
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('third_party_auth', '0001_initial'),
-    ]
-
-    operations = [
-        migrations.AlterField(
-            model_name='oauth2providerconfig',
-            name='backend_name',
-            field=models.CharField(help_text=b'Which python-social-auth OAuth2 provider backend to use. The list of backend choices is determined by the THIRD_PARTY_AUTH_BACKENDS setting.', max_length=50, db_index=True, choices=[(b'google-oauth2', b'google-oauth2'), (b'linkedin-oauth2', b'linkedin-oauth2'), (b'facebook', b'facebook'), (b'twitter', b'twitter'), (b'dummy', b'dummy')]),
-        ),
-        migrations.AlterField(
-            model_name='samlproviderconfig',
-            name='backend_name',
-            field=models.CharField(default=b'tpa-saml', help_text=b"Which python-social-auth provider backend to use. 'tpa-saml' is the standard edX SAML backend.", max_length=50, choices=[(b'tpa-saml', b'tpa-saml')]),
-        ),
-    ]

common/djangoapps/third_party_auth/models.py

@@ -212,7 +212,7 @@ class OAuth2ProviderConfig(ProviderConfig):
     prefix = 'oa2'
     KEY_FIELDS = ('backend_name', )  # Backend name is unique
     backend_name = models.CharField(
-        max_length=50, choices=[(name, name) for name in _PSA_OAUTH2_BACKENDS], blank=False, db_index=True,
+        max_length=50, blank=False, db_index=True,
         help_text=(
             "Which python-social-auth OAuth2 provider backend to use. "
             "The list of backend choices is determined by the THIRD_PARTY_AUTH_BACKENDS setting."
@@ -265,7 +265,7 @@ class SAMLProviderConfig(ProviderConfig):
     prefix = 'saml'
     KEY_FIELDS = ('idp_slug', )
     backend_name = models.CharField(
-        max_length=50, default='tpa-saml', choices=[(name, name) for name in _PSA_SAML_BACKENDS], blank=False,
+        max_length=50, default='tpa-saml', blank=False,
         help_text="Which python-social-auth provider backend to use. 'tpa-saml' is the standard edX SAML backend.")
     idp_slug = models.SlugField(
         max_length=30, db_index=True,