python 2.7 - Django Model __unicode__ raising exception when logging -

i have model class looks following:

class address(models.model):     # taking length of address/city fields existing userprofile model     address_1 = models.charfield(max_length=128,                                  blank=false,                                  null=false)      address_2 = models.charfield(max_length=128,                                  blank=true,                                  null=true)      address_3 = models.charfield(max_length=128,                                  blank=true,                                  null=true)      unit = models.charfield(max_length=10,                             blank=true,                             null=true)      city = models.charfield(max_length=128,                             blank=false,                             null=false)      state_or_province = models.foreignkey(stateorprovince)      postal_code = models.charfield(max_length=20,                                    blank=false,                                    null=false)      phone = models.charfield(max_length=20,                              blank=true,                              null=true)      is_deleted = models.booleanfield(default=false,                                      null=false)      def __unicode__(self):         return u"{}, {} {}, {}".format(             self.city, self.state_or_province.postal_abbrev, self.postal_code, self.address_1) 

the key being __unicode__ method. have customer model has foreign key field table, , doing following logging:

log.debug(u'generated customer [{}]'.format(vars(customer))) 

this works fine, if address_1 field value contains non ascii value,

57562 vån ness hwy

the system throwing following exception:

unicodedecodeerror: 'ascii' codec can't decode byte 0xc3 in position 345: ordinal not in range(128) 

i tracked down strange method in django/db/models/base.py:

def __repr__(self):         try:             u = six.text_type(self)         except (unicodeencodeerror, unicodedecodeerror):             u = '[bad unicode data]'         return force_str('<%s: %s>' % (self.__class__.__name__, u)) 

as can see, method getting called force_str, doesn't handled correctly. bug? if unicode getting called on object, shouldn't in unicode?

according docs, when python object passed argument '{}'.format(obj),

a general convention empty format string ("") [within "{}"] produces same result if had called str() on value.

this means you're calling str(vars(customer)), , vars(customer) returns dict.

calling str() on dict call repr() on keys , values because otherwise you'd ambiguous output (eg str(1) == str('1') == '1' repr(1) == '1' , repr('1') == '"1"' (see difference between __str__ , __repr__ in python)

therefore repr() still being called on address, returns string.

now returning unicode repr() not allowed in python 2 - https://stackoverflow.com/a/3627835/648176, you'll need either override __str__() in model make handle decoding ascii (django docs), or like:

string_dict = {str(k): str(v) (k, v) in vars(customer).items()} log.debug(u'generated customer [{}]'.format(string_dict))