[IMP] make an onchange for location_id, fix readme

mrp_bom_location/README.rst

@@ -20,6 +20,9 @@ Usage
 To use this module, you need to:
 
 #. Go to *Manufacturing > Bill of Materials*.
+#. Pick or create one of them.
+#. You will see a new field to fill called "Location".
+#. One the structure report *BOM > Print > BOM Structure* location field is present
 
 .. image:: https://odoo-community.org/website/image/ir.attachment/5784_f2813bd/datas
    :alt: Try me on Runbot
@@ -45,6 +48,7 @@ Contributors
 ------------
 
 * Lois Rilo <lois.rilo@eficent.com>
+* Mykhailo Panarin <m.panarin@mobilunity.com>
 
 Do not contact contributors directly about support or help with technical
 issues.

mrp_bom_location/models/mrp_bom.py

@@ -1,24 +1,29 @@
 # Copyright 2017 Eficent Business and IT Consulting Services S.L.
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 
-from odoo import fields, models
+from odoo import api, fields, models
 
 
 class MrpBom(models.Model):
     _inherit = "mrp.bom"
 
     location_id = fields.Many2one(
-        related='picking_type_id.default_location_dest_id',
-        readonly=True,
-        store=True,
+        string='Location',
+        comodel_name='stock.location',
     )
 
+    @api.onchange('picking_type_id')
+    def _onchange_picking_type_id(self):
+        if (self.picking_type_id and
+                self.picking_type_id.default_location_src_id):
+            self.location_id = self.picking_type_id.default_location_src_id
+
 
 class MrpBomLine(models.Model):
     _inherit = "mrp.bom.line"
 
     location_id = fields.Many2one(
-        related='bom_id.picking_type_id.default_location_src_id',
+        related='bom_id.location_id',
         readonly=True,
         store=True,
     )

mrp_bom_location/report/bom_structure.py

@@ -6,7 +6,7 @@ from odoo import api, models
 
 
 class BomStructureReport(models.AbstractModel):
-    _name = 'report.mrp.mrp_bom_structure_report'
+    _inherit = 'report.mrp.mrp_bom_structure_report'
 
     @staticmethod
     def _get_child_vals(record, level, qty, uom):