[FIX] base: fix users' groups assignation

Avoid sharing of users'groups when writing on multiple users.

When changing groups of multiple users, all implied groups were shared
between written users.

Oversight of new-api rewrite.

Fixes #26036

odoo/addons/base/res/res_users.py

@@ -679,7 +679,7 @@ class UsersImplied(models.Model):
             for user in self.with_context({}):
                 gs = set(concat(g.trans_implied_ids for g in user.groups_id))
                 vals = {'groups_id': [(4, g.id) for g in gs]}
-                super(UsersImplied, self).write(vals)
+                super(UsersImplied, user).write(vals)
         return res
 
 #

odoo/addons/base/tests/__init__.py

@@ -31,3 +31,4 @@ import test_view_validation
 import test_views
 import test_xmlrpc
 import test_res_partner_bank
+import test_non_regression

odoo/addons/base/tests/test_non_regression.py

@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+"""
+    Non-Regression Tests
+"""
+
+from openerp.tests.common import TransactionCase
+
+
+class TestNR(TransactionCase):
+    def test_issue26036(self):
+        U = self.env["res.users"]
+        G = self.env["res.groups"]
+
+        group_A = G.create({"name": "A"})
+        group_AA = G.create({"name": "AA", "implied_ids": [(6, 0, [group_A.id])]})
+        group_B = G.create({"name": "B"})
+        group_BB = G.create({"name": "BB", "implied_ids": [(6, 0, [group_B.id])]})
+        group_C = G.create({"name": "C"})
+
+        user_a = U.create({"name": "a", "login": "a", "groups_id": [(6, 0, [group_AA.id])]})
+        user_b = U.create({"name": "b", "login": "b", "groups_id": [(6, 0, [group_BB.id])]})
+
+        (user_a + user_b).write({"groups_id": [(4, group_C.id)]})
+
+        self.assertEqual(user_a.groups_id, (group_AA + group_A + group_C))
+        self.assertEqual(user_b.groups_id, (group_BB + group_B + group_C))