Money field requiring new migration even though models.py wasn't touched

[vtbassmatt]

I have a money field defined in what I think is the normal way:

from myplatform.models import AbstractBaseModel
from djmoney.models.fields import MoneyField
class Sale(AbstractBaseModel):
    price = MoneyField(max_digits=10, decimal_places=2, default_currency="USD")

AbstractBaseModel does some user and date bookkeeping for me.

I'm using Django 1.7.3 on Python 3.4.2. Every so often, without me changing anything in any of my models.py files, manage.py will inform me that I have migrations I need to make. Only my money field will get a migration, and it'll be a differently-ordered but semantically equivalent of exactly what was there before.

File 0006_auto_20150125_1600.py:

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models, migrations
import djmoney.models.fields

class Migration(migrations.Migration):

    dependencies = [
        ('myapp', '0005_auto_20150125_0326'),
    ]

    operations = [
        migrations.AlterField(
            model_name='sale',
            name='price_currency',
            field=djmoney.models.fields.CurrencyField(choices=[('AFN', 'Afghani'), ('DZD', 'Algerian Dinar'), ('ARS', 'Argentine Peso'), ('AMD', 'Armenian Dram'), ('AWG', 'Aruban Guilder'), ('AUD', 'Australian Dollar'), ('AZN', 'Azerbaijanian Manat'), ('BSD', 'Bahamian Dollar'), ('BHD', 'Bahraini Dinar'), ('THB', 'Baht'), ('BBD', 'Barbados Dollar'), ('BYR', 'Belarussian Ruble'), ('BZD', 'Belize Dollar'), ('BMD', 'Bermudian Dollar (customarily known as Bermuda Dollar)'), ('BTN', 'Bhutanese ngultrum'), ('VEF', 'Bolivar Fuerte'), ('XBA', 'Bond Markets Units European Composite Unit (EURCO)'), ('BRL', 'Brazilian Real'), ('BND', 'Brunei Dollar'), ('BGN', 'Bulgarian Lev'), ('BIF', 'Burundi Franc'), ('XOF', 'CFA Franc BCEAO'), ('XAF', 'CFA franc BEAC'), ('XPF', 'CFP Franc'), ('CAD', 'Canadian Dollar'), ('CVE', 'Cape Verde Escudo'), ('KYD', 'Cayman Islands Dollar'), ('CLP', 'Chilean peso'), ('XTS', 'Codes specifically reserved for testing purposes'), ('COP', 'Colombian peso'), ('KMF', 'Comoro Franc'), ('CDF', 'Congolese franc'), ('BAM', 'Convertible Marks'), ('NIO', 'Cordoba Oro'), ('CRC', 'Costa Rican Colon'), ('HRK', 'Croatian Kuna'), ('CUP', 'Cuban Peso'), ('CUC', 'Cuban convertible peso'), ('CZK', 'Czech Koruna'), ('GMD', 'Dalasi'), ('DKK', 'Danish Krone'), ('MKD', 'Denar'), ('DJF', 'Djibouti Franc'), ('STD', 'Dobra'), ('DOP', 'Dominican Peso'), ('VND', 'Dong'), ('XCD', 'East Caribbean Dollar'), ('EGP', 'Egyptian Pound'), ('ETB', 'Ethiopian Birr'), ('EUR', 'Euro'), ('XBB', 'European Monetary Unit (E.M.U.-6)'), ('XBD', 'European Unit of Account 17(E.U.A.-17)'), ('XBC', 'European Unit of Account 9(E.U.A.-9)'), ('FKP', 'Falkland Islands Pound'), ('FJD', 'Fiji Dollar'), ('HUF', 'Forint'), ('GHS', 'Ghana Cedi'), ('GIP', 'Gibraltar Pound'), ('XAU', 'Gold'), ('XFO', 'Gold-Franc'), ('PYG', 'Guarani'), ('GNF', 'Guinea Franc'), ('GYD', 'Guyana Dollar'), ('HTG', 'Haitian gourde'), ('HKD', 'Hong Kong Dollar'), ('UAH', 'Hryvnia'), ('ISK', 'Iceland Krona'), ('INR', 'Indian Rupee'), ('IRR', 'Iranian Rial'), ('IQD', 'Iraqi Dinar'), ('IMP', 'Isle of Man pount'), ('JMD', 'Jamaican Dollar'), ('JOD', 'Jordanian Dinar'), ('KES', 'Kenyan Shilling'), ('PGK', 'Kina'), ('LAK', 'Kip'), ('EEK', 'Kroon'), ('KWD', 'Kuwaiti Dinar'), ('MWK', 'Kwacha'), ('ZMK', 'Kwacha'), ('AOA', 'Kwanza'), ('MMK', 'Kyat'), ('GEL', 'Lari'), ('LVL', 'Latvian Lats'), ('LBP', 'Lebanese Pound'), ('ALL', 'Lek'), ('HNL', 'Lempira'), ('SLL', 'Leone'), ('LSL', 'Lesotho loti'), ('LRD', 'Liberian Dollar'), ('LYD', 'Libyan Dinar'), ('SZL', 'Lilangeni'), ('LTL', 'Lithuanian Litas'), ('MGA', 'Malagasy Ariary'), ('MYR', 'Malaysian Ringgit'), ('TMM', 'Manat'), ('MUR', 'Mauritius Rupee'), ('MZN', 'Metical'), ('MXN', 'Mexixan peso'), ('MDL', 'Moldovan Leu'), ('MAD', 'Moroccan Dirham'), ('NGN', 'Naira'), ('ERN', 'Nakfa'), ('NAD', 'Namibian Dollar'), ('NPR', 'Nepalese Rupee'), ('ANG', 'Netherlands Antillian Guilder'), ('ILS', 'New Israeli Sheqel'), ('RON', 'New Leu'), ('TWD', 'New Taiwan Dollar'), ('NZD', 'New Zealand Dollar'), ('KPW', 'North Korean Won'), ('NOK', 'Norwegian Krone'), ('PEN', 'Nuevo Sol'), ('MRO', 'Ouguiya'), ('TOP', 'Paanga'), ('PKR', 'Pakistan Rupee'), ('XPD', 'Palladium'), ('MOP', 'Pataca'), ('PHP', 'Philippine Peso'), ('XPT', 'Platinum'), ('GBP', 'Pound Sterling'), ('BWP', 'Pula'), ('QAR', 'Qatari Rial'), ('GTQ', 'Quetzal'), ('ZAR', 'Rand'), ('OMR', 'Rial Omani'), ('KHR', 'Riel'), ('MVR', 'Rufiyaa'), ('IDR', 'Rupiah'), ('RUB', 'Russian Ruble'), ('RWF', 'Rwanda Franc'), ('XDR', 'SDR'), ('SHP', 'Saint Helena Pound'), ('SAR', 'Saudi Riyal'), ('RSD', 'Serbian Dinar'), ('SCR', 'Seychelles Rupee'), ('XAG', 'Silver'), ('SGD', 'Singapore Dollar'), ('SKK', 'Slovak Koruna'), ('SBD', 'Solomon Islands Dollar'), ('KGS', 'Som'), ('SOS', 'Somali Shilling'), ('TJS', 'Somoni'), ('LKR', 'Sri Lanka Rupee'), ('SDG', 'Sudanese Pound'), ('SRD', 'Surinam Dollar'), ('SEK', 'Swedish Krona'), ('CHF', 'Swiss Franc'), ('SYP', 'Syrian Pound'), ('BDT', 'Taka'), ('WST', 'Tala'), ('TZS', 'Tanzanian Shilling'), ('KZT', 'Tenge'), ('TTD', 'Trinidad and Tobago Dollar'), ('MNT', 'Tugrik'), ('TND', 'Tunisian Dinar'), ('TRY', 'Turkish Lira'), ('TVD', 'Tuvalu dollar'), ('AED', 'UAE Dirham'), ('XFU', 'UIC-Franc'), ('USD', 'US Dollar'), ('UGX', 'Uganda Shilling'), ('UYU', 'Uruguayan peso'), ('UZS', 'Uzbekistan Sum'), ('VUV', 'Vatu'), ('KRW', 'Won'), ('YER', 'Yemeni Rial'), ('JPY', 'Yen'), ('CNY', 'Yuan Renminbi'), ('ZWD', 'Zimbabwe Dollar A/06'), ('ZWN', 'Zimbabwe dollar A/08'), ('ZWL', 'Zimbabwe dollar A/09'), ('PLN', 'Zloty')], default='USD', max_length=3, editable=False),
            preserve_default=True,
        ),
    ]

and then file 0007_auto_20150125_1815.py:

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models, migrations
import djmoney.models.fields

class Migration(migrations.Migration):

    dependencies = [
        ('myapp', '0006_auto_20150125_1600'),
    ]

    operations = [
        migrations.AlterField(
            model_name='sale',
            name='price_currency',
            field=djmoney.models.fields.CurrencyField(editable=False, default='USD', max_length=3, choices=[('AFN', 'Afghani'), ('DZD', 'Algerian Dinar'), ('ARS', 'Argentine Peso'), ('AMD', 'Armenian Dram'), ('AWG', 'Aruban Guilder'), ('AUD', 'Australian Dollar'), ('AZN', 'Azerbaijanian Manat'), ('BSD', 'Bahamian Dollar'), ('BHD', 'Bahraini Dinar'), ('THB', 'Baht'), ('BBD', 'Barbados Dollar'), ('BYR', 'Belarussian Ruble'), ('BZD', 'Belize Dollar'), ('BMD', 'Bermudian Dollar (customarily known as Bermuda Dollar)'), ('BTN', 'Bhutanese ngultrum'), ('VEF', 'Bolivar Fuerte'), ('XBA', 'Bond Markets Units European Composite Unit (EURCO)'), ('BRL', 'Brazilian Real'), ('BND', 'Brunei Dollar'), ('BGN', 'Bulgarian Lev'), ('BIF', 'Burundi Franc'), ('XOF', 'CFA Franc BCEAO'), ('XAF', 'CFA franc BEAC'), ('XPF', 'CFP Franc'), ('CAD', 'Canadian Dollar'), ('CVE', 'Cape Verde Escudo'), ('KYD', 'Cayman Islands Dollar'), ('CLP', 'Chilean peso'), ('XTS', 'Codes specifically reserved for testing purposes'), ('COP', 'Colombian peso'), ('KMF', 'Comoro Franc'), ('CDF', 'Congolese franc'), ('BAM', 'Convertible Marks'), ('NIO', 'Cordoba Oro'), ('CRC', 'Costa Rican Colon'), ('HRK', 'Croatian Kuna'), ('CUP', 'Cuban Peso'), ('CUC', 'Cuban convertible peso'), ('CZK', 'Czech Koruna'), ('GMD', 'Dalasi'), ('DKK', 'Danish Krone'), ('MKD', 'Denar'), ('DJF', 'Djibouti Franc'), ('STD', 'Dobra'), ('DOP', 'Dominican Peso'), ('VND', 'Dong'), ('XCD', 'East Caribbean Dollar'), ('EGP', 'Egyptian Pound'), ('ETB', 'Ethiopian Birr'), ('EUR', 'Euro'), ('XBB', 'European Monetary Unit (E.M.U.-6)'), ('XBD', 'European Unit of Account 17(E.U.A.-17)'), ('XBC', 'European Unit of Account 9(E.U.A.-9)'), ('FKP', 'Falkland Islands Pound'), ('FJD', 'Fiji Dollar'), ('HUF', 'Forint'), ('GHS', 'Ghana Cedi'), ('GIP', 'Gibraltar Pound'), ('XAU', 'Gold'), ('XFO', 'Gold-Franc'), ('PYG', 'Guarani'), ('GNF', 'Guinea Franc'), ('GYD', 'Guyana Dollar'), ('HTG', 'Haitian gourde'), ('HKD', 'Hong Kong Dollar'), ('UAH', 'Hryvnia'), ('ISK', 'Iceland Krona'), ('INR', 'Indian Rupee'), ('IRR', 'Iranian Rial'), ('IQD', 'Iraqi Dinar'), ('IMP', 'Isle of Man pount'), ('JMD', 'Jamaican Dollar'), ('JOD', 'Jordanian Dinar'), ('KES', 'Kenyan Shilling'), ('PGK', 'Kina'), ('LAK', 'Kip'), ('EEK', 'Kroon'), ('KWD', 'Kuwaiti Dinar'), ('ZMK', 'Kwacha'), ('MWK', 'Kwacha'), ('AOA', 'Kwanza'), ('MMK', 'Kyat'), ('GEL', 'Lari'), ('LVL', 'Latvian Lats'), ('LBP', 'Lebanese Pound'), ('ALL', 'Lek'), ('HNL', 'Lempira'), ('SLL', 'Leone'), ('LSL', 'Lesotho loti'), ('LRD', 'Liberian Dollar'), ('LYD', 'Libyan Dinar'), ('SZL', 'Lilangeni'), ('LTL', 'Lithuanian Litas'), ('MGA', 'Malagasy Ariary'), ('MYR', 'Malaysian Ringgit'), ('TMM', 'Manat'), ('MUR', 'Mauritius Rupee'), ('MZN', 'Metical'), ('MXN', 'Mexixan peso'), ('MDL', 'Moldovan Leu'), ('MAD', 'Moroccan Dirham'), ('NGN', 'Naira'), ('ERN', 'Nakfa'), ('NAD', 'Namibian Dollar'), ('NPR', 'Nepalese Rupee'), ('ANG', 'Netherlands Antillian Guilder'), ('ILS', 'New Israeli Sheqel'), ('RON', 'New Leu'), ('TWD', 'New Taiwan Dollar'), ('NZD', 'New Zealand Dollar'), ('KPW', 'North Korean Won'), ('NOK', 'Norwegian Krone'), ('PEN', 'Nuevo Sol'), ('MRO', 'Ouguiya'), ('TOP', 'Paanga'), ('PKR', 'Pakistan Rupee'), ('XPD', 'Palladium'), ('MOP', 'Pataca'), ('PHP', 'Philippine Peso'), ('XPT', 'Platinum'), ('GBP', 'Pound Sterling'), ('BWP', 'Pula'), ('QAR', 'Qatari Rial'), ('GTQ', 'Quetzal'), ('ZAR', 'Rand'), ('OMR', 'Rial Omani'), ('KHR', 'Riel'), ('MVR', 'Rufiyaa'), ('IDR', 'Rupiah'), ('RUB', 'Russian Ruble'), ('RWF', 'Rwanda Franc'), ('XDR', 'SDR'), ('SHP', 'Saint Helena Pound'), ('SAR', 'Saudi Riyal'), ('RSD', 'Serbian Dinar'), ('SCR', 'Seychelles Rupee'), ('XAG', 'Silver'), ('SGD', 'Singapore Dollar'), ('SKK', 'Slovak Koruna'), ('SBD', 'Solomon Islands Dollar'), ('KGS', 'Som'), ('SOS', 'Somali Shilling'), ('TJS', 'Somoni'), ('LKR', 'Sri Lanka Rupee'), ('SDG', 'Sudanese Pound'), ('SRD', 'Surinam Dollar'), ('SEK', 'Swedish Krona'), ('CHF', 'Swiss Franc'), ('SYP', 'Syrian Pound'), ('BDT', 'Taka'), ('WST', 'Tala'), ('TZS', 'Tanzanian Shilling'), ('KZT', 'Tenge'), ('TTD', 'Trinidad and Tobago Dollar'), ('MNT', 'Tugrik'), ('TND', 'Tunisian Dinar'), ('TRY', 'Turkish Lira'), ('TVD', 'Tuvalu dollar'), ('AED', 'UAE Dirham'), ('XFU', 'UIC-Franc'), ('USD', 'US Dollar'), ('UGX', 'Uganda Shilling'), ('UYU', 'Uruguayan peso'), ('UZS', 'Uzbekistan Sum'), ('VUV', 'Vatu'), ('KRW', 'Won'), ('YER', 'Yemeni Rial'), ('JPY', 'Yen'), ('CNY', 'Yuan Renminbi'), ('ZWD', 'Zimbabwe Dollar A/06'), ('ZWN', 'Zimbabwe dollar A/08'), ('ZWL', 'Zimbabwe dollar A/09'), ('PLN', 'Zloty')]),
            preserve_default=True,
        ),
    ]

I pulled the choices fields into the Python shell. ran set() over them, and they compare identically. As far as I can tell, this is just a serialization hiccup.

I haven't entirely root-caused the issue, though I think it may be every time I make certain changes in settings.py. (But not any change in settings.py, which is why it's been frustrating to track down.)

Has anyone else seen this, or do the core devs know what's going on? It's essentially a nuisance, not a "real" bug, but it would be nice to stop cluttering up my migrations folder with meaningless AlterFields. Thanks in advance!

[OmegaDroid]

I am seeing a similar issue however I don't believe it is triggered to a settings change. With no changes to the code base I get migrations being produced for different apps. I ran:

git clean -f
manage.py makemigrations
git clean -f
manage.py makemigrations 

and saw two different results:

Migrations for 'bookings':
  0014_auto_20150407_1055.py:
    - Alter field price_currency on bookingticket

Migrations for 'providers':
  0016_auto_20150407_1056.py:
    - Alter field price_per_click_currency on provider
    - Alter field cost_currency on providerreferral

If I run makemigrations several times with no changes to the code base I see the same results as @vtbassmatt

[jneves]

I've investigated this a bit and the origin of the issue is that the choices array for a CurrencyField is generated. In the end the list passed on the choices argument is different for the new and old field (they have different ids as reported by id()), causing the Django 1.7 migration code to believe that it has changed.

[jneves]

Noting that the issue is not reliable. It doesn't happen every time you run makemigrations for each field.

[jneves]

Ok, found the cause: forms/widgets.py orders the currency by name. moneyed has two different currencies with the name Kwacha for the Malawian Kwacha (MWK) and the Zambian Kwacha (ZMK). So when CURRENCY_CHOICES is built the sort will not always produce the same list.

I would argue that this is actually a bug in moneyed, as the name should be the only thing visible to the user and, as such, should be unique.

django-money could implement a workaround by changing the line in forms/widget.py from CURRENCY_CHOICES.sort(key=operator.itemgetter(1)) to CURRENCY_CHOICES.sort(key=operator.itemgetter(1, 0)).

If you are not using one of the currencies above you might just remove it using CURRENCIES on your settings.py.

[jneves]

Opened an issue with moneyed: https://github.com/limist/py-moneyed/issues/55

[vtbassmatt]

Thanks - sounds good.

[benjaoming]

Thanks for opening up the other issue and getting it fixed in moneyed!