feat: don't allow password login for SAML user

app/controllers/devise_overrides/sessions_controller.rb

@@ -3,6 +3,7 @@ class DeviseOverrides::SessionsController < DeviseTokenAuth::SessionsController
   # Unpermitted parameter: session
   wrap_parameters format: []
   before_action :process_sso_auth_token, only: [:create]
+  before_action :check_saml_user, only: [:create]
 
   def new
     redirect_to login_page_url(error: 'access-denied')
@@ -46,6 +47,24 @@ class DeviseOverrides::SessionsController < DeviseTokenAuth::SessionsController
     user = User.from_email(params[:email])
     @resource = user if user&.valid_sso_auth_token?(params[:sso_auth_token])
   end
+
+  def check_saml_user
+    # Skip if using SSO token (SAML users can use SSO tokens)
+    return if params[:sso_auth_token].present?
+    return if params[:email].blank?
+
+    user = User.from_email(params[:email])
+    return unless user&.saml_user?
+
+    render_saml_user_error
+  end
+
+  def render_saml_user_error
+    render json: {
+      success: false,
+      errors: [I18n.t('messages.login_saml_user')]
+    }, status: :unauthorized
+  end
 end
 
 DeviseOverrides::SessionsController.prepend_mod_with('DeviseOverrides::SessionsController')