[FIX] website_sale: check email address

Partial backport of ef19830. The error message cannot be included for
compatibility reason, but the browser will highlight the field in red,
which should be enough to locate the error.

opw-677121

addons/website_sale/controllers/main.py

@@ -4,6 +4,7 @@ import werkzeug
 
 from openerp import SUPERUSER_ID
 from openerp import http
+from openerp import tools
 from openerp.http import request
 from openerp.tools.translate import _
 from openerp.addons.website.models.website import slug
@@ -533,6 +534,10 @@ class website_sale(http.Controller):
             if not data.get(field_name):
                 error[field_name] = 'missing'
 
+        # email validation
+        if data.get('email') and not tools.single_email_re.match(data.get('email')):
+            error["email"] = 'error'
+
         if data.get("vat") and hasattr(registry["res.partner"], "check_vat"):
             if request.website.company_id.vat_check_vies:
                 # force full VIES online check