Handle unconfirmed email message in UserSessionsController

app/controllers/spree/user_sessions_controller.rb

@@ -13,6 +13,7 @@ module Spree
 
     helper 'spree/base'
 
+    prepend_before_action :handle_unconfirmed_email
     before_action :set_checkout_redirect, only: :create
     after_action :ensure_valid_locale_persisted, only: :create
 
@@ -49,6 +50,22 @@ module Spree
       Spree.t(:login)
     end
 
+    def handle_unconfirmed_email
+      render_unconfirmed_response if email_unconfirmed?
+    end
+
+    def email_unconfirmed?
+      Spree::User.where(email: params.dig(:spree_user, :email), confirmed_at: nil).exists?
+    end
+
+    def render_unconfirmed_response
+      render status: :unprocessable_entity, operations: cable_car.inner_html(
+        "#login-feedback",
+        partial("layouts/alert",
+                locals: { type: "alert", message: t(:email_unconfirmed), unconfirmed: true })
+      )
+    end
+
     def ensure_valid_locale_persisted
       # When creating a new user session we have to wait until after a successful
       # login to be able to persist a selected locale on the current user