[15.0][FIX] mail_activity_done: KeyError user_activites[model.model]

A KeyError occurs for a missing model in the user_activities, when
updating the user_activites[model.model] dict.

The fix to initialize the activity data wasn't straightforward.
However just backporting (copied) the code from 16.0 seems to work!

mail_activity_done/models/res_users.py

@@ -3,69 +3,60 @@
 # License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl.html).
 from collections import defaultdict
 
-from odoo import api, fields, models
+from odoo import api, fields, models, modules
 
 
 class ResUsers(models.Model):
     _inherit = "res.users"
 
     @api.model
     def systray_get_activities(self):
-        # TODO: Simplify if Odoo allows to modify query
-        res = super().systray_get_activities()
-        # Convert list to dict
-        user_activities = {}
-        for item in res:
-            user_activities[item["model"]] = item
-        # Redo the method only with the archived records and subtract them.
-        query = """SELECT array_agg(res_id) as res_ids, m.id, count(*),
-                    CASE
-                        WHEN %(today)s::date - act.date_deadline::date = 0 Then 'today'
-                        WHEN %(today)s::date - act.date_deadline::date > 0 Then 'overdue'
-                        WHEN %(today)s::date - act.date_deadline::date < 0 Then 'planned'
-                    END AS states
-                FROM mail_activity AS act
-                JOIN ir_model AS m ON act.res_model_id = m.id
-                WHERE user_id = %(user_id)s
-                AND act.active = False
-                GROUP BY m.id, states;
-                """
+        # Here we totally override the method. Not very nice, but
+        # we should perhaps ask Odoo to add a hook here.
+        query = """SELECT m.id, count(*), act.res_model as model,
+                        CASE
+                            WHEN %(today)s::date -
+                            act.date_deadline::date = 0 Then 'today'
+                            WHEN %(today)s::date -
+                            act.date_deadline::date > 0 Then 'overdue'
+                            WHEN %(today)s::date -
+                            act.date_deadline::date < 0 Then 'planned'
+                        END AS states
+                    FROM mail_activity AS act
+                    JOIN ir_model AS m ON act.res_model_id = m.id
+                    WHERE user_id = %(user_id)s
+                    AND act.done = False
+                    GROUP BY m.id, states, act.res_model;
+                    """
         self.env.cr.execute(
-            query,
-            {
-                "today": fields.Date.context_today(self),
-                "user_id": self.env.uid,
-            },
+            query, {"today": fields.Date.context_today(self), "user_id": self.env.uid}
         )
         activity_data = self.env.cr.dictfetchall()
-        records_by_state_by_model = defaultdict(
-            lambda: {"today": set(), "overdue": set(), "planned": set(), "all": set()}
-        )
-        for data in activity_data:
-            records_by_state_by_model[data["id"]][data["states"]] = set(data["res_ids"])
-            records_by_state_by_model[data["id"]]["all"] = records_by_state_by_model[
-                data["id"]
-            ]["all"] | set(data["res_ids"])
-        for model_id in records_by_state_by_model:
-            model_dic = records_by_state_by_model[model_id]
-            model = (
-                self.env["ir.model"]
-                .sudo()
-                .browse(model_id)
-                .with_prefetch(tuple(records_by_state_by_model.keys()))
-            )
-            allowed_records = self.env[model.model].search(
-                [("id", "in", tuple(model_dic["all"]))]
-            )
-            if not allowed_records:
-                continue
-            today = len(model_dic["today"] & set(allowed_records.ids))
-            overdue = len(model_dic["overdue"] & set(allowed_records.ids))
-            # Decrease total
-            user_activities[model.model]["total_count"] -= today + overdue
-            user_activities[model.model]["today_count"] -= today
-            user_activities[model.model]["overdue_count"] -= overdue
-            user_activities[model.model]["planned_count"] -= len(
-                model_dic["planned"] & set(allowed_records.ids)
-            )
+        model_ids = [a["id"] for a in activity_data]
+        model_names = {
+            n[0]: n[1] for n in self.env["ir.model"].sudo().browse(model_ids).name_get()
+        }
+
+        user_activities = {}
+        for activity in activity_data:
+            if not user_activities.get(activity["model"]):
+                module = self.env[activity["model"]]._original_module
+                icon = module and modules.module.get_module_icon(module)
+                user_activities[activity["model"]] = {
+                    "id": activity["id"],
+                    "name": model_names[activity["id"]],
+                    "model": activity["model"],
+                    "icon": icon,
+                    "total_count": 0,
+                    "today_count": 0,
+                    "overdue_count": 0,
+                    "planned_count": 0,
+                    "type": "activity",
+                }
+            user_activities[activity["model"]][
+                "%s_count" % activity["states"]
+            ] += activity["count"]
+            if activity["states"] in ("today", "overdue"):
+                user_activities[activity["model"]]["total_count"] += activity["count"]
+
         return list(user_activities.values())