[IMP] sale_exception: too many write on sale.order.line

Although the ORM will properly handle multiple write (as mentioned in
the comment)
Without the filtering the write method will still be called many time
without need.

Author: Thierry Ducrest

sale_exception/models/sale_order_line.py

@@ -56,6 +56,12 @@ def _detect_exceptions(self, rule):
         # Thanks to the new flush of odoo 13.0, queries will be optimized
         # together at the end even if we update the exception_ids many times.
         # On previous versions, this could be unoptimized.
-        (self - records).exception_ids = [Command.unlink(rule.id)]
-        records.exception_ids = [Command.link(rule.id)]
+        lines_to_remove_exception = (self - records).filtered(
+            lambda line: rule.id in line.exception_ids.ids
+        )
+        lines_to_remove_exception.exception_ids = [Command.unlink(rule.id)]
+        lines_to_add_exception = records.filtered(
+            lambda line: rule.id not in line.exception_ids.ids
+        )
+        lines_to_add_exception.exception_ids = [Command.link(rule.id)]
         return records.mapped("order_id")