Add area location relation

So we can use it in group-by and filters. Note that we can have several
levels of areas... only the top-level will be used.

This commit fixes the computed field dependencies:
_compute_location_kind should have a dependency on both it's parent's
location_kind and on its child_ids to know if we are in a bin. This
can't work without triggering an infinite loop. The trick used here is
to split the computation of 'zone_location_id + area_location_id' in one
computed method, and move the computation of the kind in a different
method with triggers an the current record's zone_location +
area_location_id, but not on the parent.

Plus the zone_location_id and area_location_id do not depend anymore on
the parent's kind, which is the reason for the infinite loop.

stock_location_zone/models/stock_location.py

@@ -16,11 +16,17 @@ class StockLocation(models.Model):
 
     zone_location_id = fields.Many2one(
         'stock.location',
-        string='Location zone',
-        compute='_compute_location_zone',
+        string='Location Zone',
+        compute='_compute_zone_location_id',
         store=True,
         index=True,
     )
+    area_location_id = fields.Many2one(
+        'stock.location',
+        string='Location Area',
+        compute='_compute_zone_location_id',
+        store=True,
+    )
 
     location_kind = fields.Selection(
         [
@@ -31,61 +37,71 @@ class StockLocation(models.Model):
             ('other', 'Other'),
         ],
         string='Location Kind',
-        compute='_compute_location_zone',
-        help='Group location according to their kinds:'
-             '* Zone: locations that are flagged as being zones'
-             '* Area: locations with children that are part of a zone'
-             '* Bin: locations without children that are part of a zone'
-             '* Stock: internal locations whose parent is a view'
+        compute='_compute_location_kind',
+        store=True,
+        help='Group location according to their kinds: '
+             '* Zone: locations that are flagged as being zones '
+             '* Area: locations with children that are part of a zone '
+             '* Bin: locations without children that are part of a zone '
+             '* Stock: internal locations whose parent is a view '
              '* Other: any other location',
     )
 
-    @api.depends('is_zone', 'usage', 'location_id.usage', 'child_ids',
-                 'location_id.is_zone')
-    def _compute_location_zone(self):
+    @api.depends('is_zone', 'location_id.zone_location_id',
+                 'location_id.area_location_id')
+    def _compute_zone_location_id(self):
         for location in self:
+            location.zone_location_id = self.browse()
+            location.area_location_id = self.browse()
             if location.is_zone:
-                location.location_kind = 'zone'
                 location.zone_location_id = location
                 continue
-
-            # Get the zone from the parents
             parent = location.location_id
-            while parent:
-                if parent.is_zone:
-                    zone_location = parent
-                    break
-                parent = parent.location_id
-            else:
-                zone_location = self.browse()
+            if parent.zone_location_id:
+                location.zone_location_id = parent.zone_location_id
+                # If we have more than one level of area in a zone,
+                # the grouping is done by the first level
+                if parent.area_location_id:
+                    location.area_location_id = parent.area_location_id
+                else:
+                    location.area_location_id = location
 
-            location.zone_location_id = zone_location
+    @api.depends('usage', 'location_id.usage',
+                 'child_ids',
+                 'area_location_id',
+                 'zone_location_id')
+    def _compute_location_kind(self):
+        for location in self:
+            if location.zone_location_id and not location.area_location_id:
+                location.location_kind = 'zone'
+                continue
 
-            # Internal locations whose parent is view are main stocks
+            parent = location.location_id
             if (
                 location.usage == 'internal'
-                and location.location_id.usage == 'view'
+                and parent.usage == 'view'
             ):
+                # Internal locations whose parent is view are main stocks
                 location.location_kind = 'stock'
-                continue
-            # Internal locations having a zone and no children are bins
-            if (
+            elif (
+                # Internal locations having a zone and no children are bins
                 location.usage == 'internal'
-                and zone_location
+                and location.zone_location_id
+                and location.area_location_id
                 and not location.child_ids
             ):
                 location.location_kind = 'bin'
-                continue
-            # Internal locations having a zone and children are areas
-            if (
+            elif (
                 location.usage == 'internal'
-                and zone_location
+                and location.zone_location_id
+                and location.area_location_id
                 and location.child_ids
             ):
+                # Internal locations having a zone and children are areas
                 location.location_kind = 'area'
-                continue
-            # All the rest are other locations
-            location.location_kind = 'other'
+            else:
+                # All the rest are other locations
+                location.location_kind = 'other'
 
     @api.multi
     @api.returns('self', lambda value: value.id)

stock_location_zone/views/stock_location.xml

@@ -12,6 +12,7 @@
             <field name="usage" position="after">
                 <field name="location_kind" />
                 <field name="zone_location_id" />
+                <field name="area_location_id" />
             </field>
         </field>
     </record>
@@ -25,9 +26,11 @@
                 <field name="location_kind"/>
                 <field name="is_zone" />
                 <field name="zone_location_id" />
+                <field name="area_location_id" />
                 <group expand="0" string="Group By">
                     <filter string="Location Kind" name="location_kind" domain="[]" context="{'group_by':'location_kind'}"/>
                     <filter string="Zone location" name="zone_location" domain="[]" context="{'group_by':'zone_location_id'}"/>
+                    <filter string="Area location" name="area_location" domain="[]" context="{'group_by':'area_location_id'}"/>
                 </group>
             </xpath>
         </field>