[IMP] cetmix_tower_server: Validation message

- Improve validation error message

Task: 4253

cetmix_tower_server/models/cx_tower_server_template.py

@@ -2,7 +2,7 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 
 from odoo import _, api, fields, models
-from odoo.exceptions import UserError, ValidationError
+from odoo.exceptions import ValidationError
 
 
 class CxTowerServerTemplate(models.Model):
@@ -332,12 +332,27 @@ def _prepare_server_values(self, with_template_variables=True, **kwargs):
                 )
 
                 if missing_options:
-                    raise UserError(
+                    # Map variable references to their corresponding
+                    # invalid option references.
+                    missing_options_to_variables = {
+                        var_ref: opt_ref
+                        for var_ref, opt_ref in configuration_variable_options.items()
+                        if opt_ref in missing_options
+                    }
+                    # Generate a detailed error message for invalid variable options.
+                    detailed_message = "\n".join(
                         _(
-                            "Option with references '%(references)s' "
-                            "is not found for variables.",
-                            references=", ".join(missing_options),
+                            "Variable reference '%(var_ref)s' has an invalid "
+                            "option reference '%(opt_ref)s'."
                         )
+                        % {"var_ref": var_ref, "opt_ref": opt_ref}
+                        for var_ref, opt_ref in missing_options_to_variables.items()
+                    )
+                    raise ValidationError(
+                        _("Some variable options are invalid:\n%(detailed_message)s")
+                        % {
+                            "detailed_message": detailed_message,
+                        }
                     )
 
                 # Map variable options to their IDs.