Ensure backward compatibility with kerberos_spnego omniauth provider

Signed-off-by: Marin Hannache <git@mareo.fr>

config/initializers/1_settings.rb

@@ -117,6 +117,27 @@
 Settings.omniauth['session_tickets'] ||= Settingslogic.new({})
 Settings.omniauth.session_tickets['cas3'] = 'ticket'
 
+# Handle backward compatibility with the renamed kerberos_spnego provider
+# https://gitlab.com/gitlab-org/gitlab/-/merge_requests/96335#note_1094265436
+Gitlab.ee do
+  kerberos_spnego = Settings.omniauth.providers.find { |p| p.name == 'kerberos_spnego' }
+  if kerberos_spnego
+    Settings.omniauth.providers.delete_if { |p| p.name == 'kerberos' }
+    kerberos_spnego['name'] = 'kerberos'
+
+    omniauth_keys = %w(allow_single_sign_on auto_link_user external_providers sync_profile_from_provider allow_bypass_two_factor)
+    omniauth_keys.each do |key|
+      next unless Settings.omniauth[key].is_a?(Array)
+
+      Settings.omniauth[key].map! { |p| p == 'kerberos_spnego' ? 'kerberos' : p }
+    end
+
+    if Settings.omniauth['auto_sign_in_with_provider'] == 'kerberos_spnego'
+      Settings.omniauth['auto_sign_in_with_provider'] = 'kerberos'
+    end
+  end
+end
+
 # Fill out omniauth-gitlab settings. It is needed for easy set up GHE or GH by just specifying url.
 
 github_default_url = "https://github.com"