[FIX] website_forum: fix tag posts count dependencies

Post counts were not updated when a post was created or deleted
because of missing dependencies in the _compute.

Note that while "active_test" is included when counting without
specifying it, the field must be explicitly added to the `_compute`'s
dependency list to trigger it.

Task-3358143

closes odoo#125860

X-original-commit: f09291d
Signed-off-by: Stéphane Debauche (std) <std@odoo.com>

addons/website_forum/models/forum.py

@@ -1153,10 +1153,10 @@ class Tags(models.Model):
         ('name_uniq', 'unique (name, forum_id)', "Tag name already exists !"),
     ]
 
-    @api.depends("post_ids.tag_ids", "post_ids.state")
+    @api.depends("post_ids", "post_ids.tag_ids", "post_ids.state", "post_ids.active")
     def _get_posts_count(self):
         for tag in self:
-            tag.posts_count = len(tag.post_ids)
+            tag.posts_count = len(tag.post_ids)  # state filter is in field domain
 
     @api.model
     def create(self, vals):

addons/website_forum/tests/__init__.py

@@ -3,3 +3,4 @@
 from . import common
 from . import test_forum
 from . import test_forum_process
+from . import test_forum_tag

addons/website_forum/tests/test_forum_tag.py

@@ -0,0 +1,35 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo.addons.website_forum.tests.common import TestForumCommon
+
+
+class TestForumTag(TestForumCommon):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.env['forum.tag'].search([]).unlink()
+        cls.tags = cls.env['forum.tag'].create(
+            [{'forum_id': cls.forum.id, 'name': f'Test Tag {tag_idx}'} for tag_idx in range(1, 3)]
+        )
+        cls.env['forum.post'].create(
+            [{'name': 'Posting about tag 1', 'forum_id': cls.forum.id, 'tag_ids': [[6, 0, [cls.tags[0].id]]]}]
+        )
+
+    def _check_tags_post_counts(self, tags, expected_counts):
+        self.assertEqual(tags.mapped('posts_count'), expected_counts)
+
+    def test_tag_posts_count(self):
+        self._check_tags_post_counts(self.tags, [1, 0])
+        post_tag_1 = self.env['forum.post'].create(
+            [{'name': 'Posting about tag 1 again', 'forum_id': self.forum.id, 'tag_ids': [[6, 0, [self.tags[0].id]]]}]
+        )
+        self._check_tags_post_counts(self.tags, [2, 0])
+        post_tags = self.env['forum.post'].create(
+            [{'name': 'Posting about tag 2 now', 'forum_id': self.forum.id, 'tag_ids': [[6, 0, self.tags.ids]]}]
+        )
+        self._check_tags_post_counts(self.tags, [3, 1])
+        post_tag_1.active = False
+        self._check_tags_post_counts(self.tags, [2, 1])
+        post_tags.close(None)
+        self._check_tags_post_counts(self.tags, [1, 0])