[FIX] product: expand group on categories only when needed

Issue: on main product's kanban, if you group by categories, all
categories (even the empty ones) appear. This is not desired.

We only wanted this group_expand logic when using the products stat
button on the product category form view.

closes odoo/odoo#46966

X-original-commit: e3f1254e5b28aa801f137835d871427786fb3428
Signed-off-by: Simon Lejeune (sle) <sle@openerp.com>

addons/product/models/product_template.py

@@ -29,7 +29,7 @@ class ProductTemplate(models.Model):
 
     def _read_group_categ_id(self, categories, domain, order):
         category_ids = self.env.context.get('default_categ_id')
-        if not category_ids:
+        if not category_ids and self.env.context.get('group_expand'):
             category_ids = categories._search([], order=order, access_rights_uid=SUPERUSER_ID)
         return categories.browse(category_ids)
 

addons/product/views/product_views.xml

@@ -448,7 +448,7 @@
                                 name="%(product_template_action_all)d"
                                 icon="fa-th-list"
                                 type="action"
-                                context="{'search_default_categ_id': active_id, 'default_categ_id': active_id}">
+                                context="{'search_default_categ_id': active_id, 'default_categ_id': active_id, 'group_expand': True}">
                                 <div class="o_field_widget o_stat_info">
                                     <span class="o_stat_value"><field name="product_count"/></span>
                                     <span class="o_stat_text"> Products</span>