# Bug with missing depend (and solution :-) ) **URL:** \ **Category:** Developer\ **Created:** [October 7, 2024, 9:38am UTC](https://discuss.tryton.org/t/bug-with-missing-depend-and-solution/7929 "2024-10-07T09:38:00Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![maxx](https://discuss-cdn.tryton.org/user_avatar/discuss.tryton.org/maxx/32/2320_2.png) [@maxx](https://discuss.tryton.org/u/maxx)\ **Post date:** [October 7, 2024, 9:38am UTC](https://discuss.tryton.org/t/bug-with-missing-depend-and-solution/7929/1 "2024-10-07T09:38:00Z")
Hi, I recently had a strange bug since migration to 7.2 with some custos. I just want to share with you the problem I met and the solution. When creating a new purchase and clicking on “Ok” after selecting a product to add on a purchase line, I had this error: ```auto AssertionError: (Pool().get('purchase.line')({}), 'moves') ``` ![2024-10-07_11-00](https://discuss-cdn.tryton.org/uploads/default/original/2X/a/a5431fb0fc318641ea7c175e46ca4930a2365ea1.png) Here’s the traceback: ```auto 16776 140325407409856 [2024-10-04 09:01:35,513] ERROR trytond.protocols.dispatcher purchase.line.on_change_with({'product': 4425, 'id': -2, 'company': 1, 'tariff_code': None, 'product_supplier': None, 'product_secondary_uom_category': None, 'product_uom_category': None, '[_parent_purchase.party](http://_parent_purchase.party)': 1441, 'purchase': {'company': 1, 'currency': 44, 'description': '', 'id': -1, 'invoice_state': 'none', 'number': '', 'party': 1441, 'purchase_date': [datetime.date](http://datetime.date)(2024, 10, 4), 'reference': '', 'revision': 0, 'shipment_state': 'none', 'state': 'draft', 'untaxed_amount': Decimal('0.00'), 'warehouse': 5, 'alfresco_links': [], 'amendments': [], 'available_incoterms': [12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22], 'comment': '', 'confirmed_by': None, 'contact': None, 'delivery_date': None, 'incoterm': None, 'incoterm_location': None, 'incoterm_location_required': False, 'invoice_address': 1536, 'invoice_method': 'shipment', 'invoice_party': None, 'invoices': [], 'invoices_ignored': [], 'origin': None, 'party_lang': 'en', 'payment_term': None, 'quoted_by': None, 'shipping_mode': None, 'tax_amount': Decimal('0.00'), 'total_amount': Decimal('0.00')}, '[_parent_purchase.company](http://_parent_purchase.company)': 1, 'purchase_description': ''}, ['purchase_description', 'product_uom_category', 'product_secondary_uom_category', 'tariff_code'], {'client': '2be797f5-e69b-42bc-bb5b-f29db6271880', 'warehouse': 5, 'company_filter': 'one', 'employee': 16, 'company': 1, 'language': 'en', 'language_direction': 'ltr', 'groups': [7, 8, 34, 33, 1, 41, 42, 4, 10, 5, 2, 11, 6, 3, 29, 9, 12, 17, 16, 22, 35, 20, 24, 23, 40, 25, 36, 21, 26, 18, 19, 37, 14, 13, 15, 39, 38, 30], 'roles': [], 'label_printer': 4}) from admin@127.0.0.1/tryton_preciball_prod_72_test2/ in 37 ms Traceback (most recent call last): File "/home/mrichez/Workspace/tryton/issues/tryton_72_dev/trytond/trytond/protocols/dispatcher.py", line 221, in _dispatch result = rpc.result(meth(inst, *c_args, c_kwargs)) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/mrichez/Workspace/tryton/issues/tryton_72_dev/trytond/trytond/model/fields/field.py", line 195, in on_change_result return record._changed_values ^^^^^^^^^^^^^^^^^^^^^^ File "/home/mrichez/Workspace/tryton/issues/tryton_72_dev/trytond/trytond/model/modelview.py", line 891, in _changed_values assert hasattr(init_record, fname), (init_record, fname) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ AssertionError: (Pool().get('purchase.line')({}), 'moves') 16776 140325407409856 [2024-10-04 09:01:35,515] ERROR trytond.protocols.wrappers in 39 ms ``` It took me a long time to identify the problem (because my custo is quite big). I had to include step by step code to locate the problem. Here’s my custom code (which is the origin of the error message): ```auto from trytond.model import fields from trytond.pyson import Eval from trytond.pool import PoolMeta class PurchaseLine(metaclass=PoolMeta): __name__ = 'purchase.line' tariff_code = fields.Function( fields.Many2One('customs.tariff.code', "Tariff Code", states={ 'invisible': Eval('type') != 'line', }), 'on_change_with_tariff_code') @fields.depends('product', methods=['_tarif_code_pattern']) def on_change_with_tariff_code(self, name=None): if self.product: tariff_code = self.product.get_tariff_code( self._tariff_code_pattern()) if tariff_code: return tariff_code.id @fields.depends('purchase', '_parent_purchase.party') def _tariff_code_pattern(self): address = self.purchase.party.address_get(type='delivery') country = address.country if address else None party = self.purchase.party return { 'date': self.delivery_date, 'country': (country.id if country else None), 'party': (party.id if party else None), } ``` Everything is ok when doing tests. The error in my code is just a missing depend in the method “`def _tariff_code_pattern(self)`”. I forget to add depend on `delivery_date` 🙂 ```auto @fields.depends('purchase', '_parent_purchase.party', 'delivery_date') def _tariff_code_pattern(self): .... ``` Still don’t know why such error message about “`moves`” that makes really hard to find the real problem. ---
**Author:** ![pokoli](https://discuss-cdn.tryton.org/user_avatar/discuss.tryton.org/pokoli/32/22_2.png) [@pokoli](https://discuss.tryton.org/u/pokoli)\ **Post date:** [October 7, 2024, 9:40am UTC](https://discuss.tryton.org/t/bug-with-missing-depend-and-solution/7929/2 "2024-10-07T09:40:04Z")
Hi Max, Thanks for taking the effort of sharing your solutions. Could you share the full traceback of the original error? That may help others to identify that they have the same issue. ---
**Author:** ![maxx](https://discuss-cdn.tryton.org/user_avatar/discuss.tryton.org/maxx/32/2320_2.png) [@maxx](https://discuss.tryton.org/u/maxx)\ **Post date:** [October 7, 2024, 9:42am UTC](https://discuss.tryton.org/t/bug-with-missing-depend-and-solution/7929/3 "2024-10-07T09:42:59Z")
Hi Sergi, I updated the original post with the traceback. 🙂 ---
**Author:** ![JCavallo](https://discuss-cdn.tryton.org/letter_avatar_proxy/v4/letter/j/48db29/32.png) [@JCavallo](https://discuss.tryton.org/u/JCavallo)\ **Post date:** [October 7, 2024, 10:25am UTC](https://discuss.tryton.org/t/bug-with-missing-depend-and-solution/7929/4 "2024-10-07T10:25:46Z")
Hi maxx, It looks like the reason you got this error is that while the `on_change` executed, it modified the `moves` field (possibly because without the `depends` you added the code went in another branch). Since the client did not sent the `moves`, the server raised the error because it detected it is sending back modifications on a field for which it does not know the value (client side). ---
**Author:** ![ced](https://discuss-cdn.tryton.org/user_avatar/discuss.tryton.org/ced/32/1237_2.png) [@ced](https://discuss.tryton.org/u/ced)\ **Post date:** [October 7, 2024, 10:31am UTC](https://discuss.tryton.org/t/bug-with-missing-depend-and-solution/7929/5 "2024-10-07T10:31:32Z")
This is because `delivery_date` is a Function field so as it was not sent for the on\_change, it has been computed by calling the getter. The getter is accessing the `moves` so it has a depends on it (but it is not part of the definition of the view) so the depends decorator assign a default value to it as it is not know. Then you have the `moves` field which is modified for the instance and the `assert` detect it. ---
**Author:** ![system](https://discuss-cdn.tryton.org/uploads/default/original/1X/c6f8ec0a40525cdcd50058c734283450a4b3d38b.png) [@system](https://discuss.tryton.org/u/system)\ **Post date:** [October 8, 2024, 10:31am UTC](https://discuss.tryton.org/t/bug-with-missing-depend-and-solution/7929/6 "2024-10-08T10:31:33Z")
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