[FIX] auditlog: Change comparison with old field values.

Fix the comparison with old values when setting fields to empty values.
The old values for the comparison when using fast log mode were initialized
with False. This causes the problem that when a field is set to an emty value
by the user, auditlog does not create a log line because internal checks
compare False to False and do not consider logging the change. Full log mode
is not affected by this as there everything is logged by default. However,
even in fast log mode, some companies have regulatory requirements which
force them to log user actions that set empty values to fields.

Author: BT-pgaiser

auditlog/models/rule.py

@@ -463,7 +463,7 @@ def write_fast(self, vals, **kwargs):
             # afterwards as it could not represent the real state
             # of the data in the database
             vals2 = dict(vals)
-            old_vals2 = dict.fromkeys(list(vals2.keys()), False)
+            old_vals2 = dict.fromkeys(list(vals2.keys()), None)
             old_values = {id_: old_vals2 for id_ in self.ids}
             new_values = {id_: vals2 for id_ in self.ids}
             result = write_fast.origin(self, vals, **kwargs)

auditlog/tests/test_auditlog.py

@@ -343,6 +343,54 @@ def tearDown(self):
         super(TestAuditlogFast, self).tearDown()
 
 
+class TestAuditlogFastWriteEmptyValue(AuditLogRuleCommon):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.test_model = cls.env["ir.model"].search([("model", "=", "res.partner")])
+        cls.auditlog_rule = cls.create_rule(
+            {
+                "name": "test.model_res_partner",
+                "model_id": cls.test_model.id,
+                "log_type": "fast",
+                "log_read": False,
+                "log_create": False,
+                "log_write": True,
+                "log_unlink": False,
+            }
+        )
+        cls.test_record = (
+            cls.env["res.partner"]
+            .with_context(tracking_disable=True)
+            .create(
+                {
+                    "name": "testpartner3",
+                    "phone": "123",
+                }
+            )
+        )
+        cls.auditlog_rule.subscribe()
+
+    def test_when_removing_field_value_a_log_line_is_created(self):
+        self.test_record.write({"phone": False})
+        logs = self.env["auditlog.log"].search(
+            [
+                ("res_id", "=", self.test_record.id),
+                ("model_id", "=", self.test_model.id),
+            ]
+        )
+        self.assertEqual(len(logs), 1)
+        self.assertEqual(logs[0].model_name, "Contact")
+        self.assertEqual(logs[0].model_model, "res.partner")
+        log_lines = logs.mapped("line_ids")
+        self.assertEqual(len(log_lines), 1)
+        self.assertEqual(log_lines[0].field_name, "phone")
+        self.assertFalse(log_lines[0].old_value)
+        self.assertFalse(log_lines[0].old_value_text)
+        self.assertFalse(log_lines[0].new_value)
+        self.assertFalse(log_lines[0].new_value_text)
+
+
 class TestFieldRemoval(AuditLogRuleCommon):
     @classmethod
     def setUpClass(cls):