add website_membership_signup_required: force to create user before add to cart a membership product

website_membership_signup_required/models/res_users.py

@@ -0,0 +1,22 @@
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from odoo import api, models
+from odoo.http import request
+
+
+class ResUsers(models.Model):
+    _inherit = "res.users"
+
+    @api.model
+    def _get_signup_invitation_scope(self):
+        # Re-enable free signup, but ONLY for the membership add-to-cart
+        # redirection flow, even when the website is in b2b (guest checkout)
+        # mode. The marker is ephemeral: set as a query param on the redirect
+        # to /web/signup and/or as a session flag at interception time. It is
+        # cleared by the auth_signup controller override after success/login.
+        if request:
+            if request.httprequest.args.get("membership_signup"):
+                return "b2c"
+            if request.session.get("membership_signup_active"):
+                return "b2c"
+        return super()._get_signup_invitation_scope()