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Ported over Field.deconstruct() from my schema alteration branch. 

This is to help other ongoing branches which would benefit from
this functionality.
This commit is contained in:
Andrew Godwin 2013-06-28 17:26:05 +01:00
parent 8809da67a2
commit 48dd1e63bb
6 changed files with 501 additions and 1 deletions
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188
django/db/models/fields/__init__.py
View File

@ -99,7 +99,8 @@ class Field(object):
db_tablespace=None, auto_created=False, validators=[],
error_messages=None):
self.name = name
self.verbose_name = verbose_name
self.verbose_name = verbose_name # May be set by set_attributes_from_name
self._verbose_name = verbose_name # Store original for deconstruction
self.primary_key = primary_key
self.max_length, self._unique = max_length, unique
self.blank, self.null = blank, null
@ -128,14 +129,99 @@ class Field(object):
self.creation_counter = Field.creation_counter
Field.creation_counter += 1
self._validators = validators # Store for deconstruction later
self.validators = self.default_validators + validators
messages = {}
for c in reversed(self.__class__.__mro__):
messages.update(getattr(c, 'default_error_messages', {}))
messages.update(error_messages or {})
self._error_messages = error_messages # Store for deconstruction later
self.error_messages = messages
def deconstruct(self):
"""
Returns enough information to recreate the field as a 4-tuple:
* The name of the field on the model, if contribute_to_class has been run
* The import path of the field, including the class: django.db.models.IntegerField
This should be the most portable version, so less specific may be better.
* A list of positional arguments
* A dict of keyword arguments
Note that the positional or keyword arguments must contain values of the
following types (including inner values of collection types):
* None, bool, str, unicode, int, long, float, complex, set, frozenset, list, tuple, dict
* UUID
* datetime.datetime (naive), datetime.date
* top-level classes, top-level functions - will be referenced by their full import path
* Storage instances - these have their own deconstruct() method
This is because the values here must be serialised into a text format
(possibly new Python code, possibly JSON) and these are the only types
with encoding handlers defined.
There's no need to return the exact way the field was instantiated this time,
just ensure that the resulting field is the same - prefer keyword arguments
over positional ones, and omit parameters with their default values.
"""
# Short-form way of fetching all the default parameters
keywords = {}
possibles = {
"verbose_name": None,
"primary_key": False,
"max_length": None,
"unique": False,
"blank": False,
"null": False,
"db_index": False,
"default": NOT_PROVIDED,
"editable": True,
"serialize": True,
"unique_for_date": None,
"unique_for_month": None,
"unique_for_year": None,
"choices": [],
"help_text": '',
"db_column": None,
"db_tablespace": settings.DEFAULT_INDEX_TABLESPACE,
"auto_created": False,
"validators": [],
"error_messages": None,
}
attr_overrides = {
"unique": "_unique",
"choices": "_choices",
"error_messages": "_error_messages",
"validators": "_validators",
"verbose_name": "_verbose_name",
}
equals_comparison = set(["choices", "validators", "db_tablespace"])
for name, default in possibles.items():
value = getattr(self, attr_overrides.get(name, name))
if name in equals_comparison:
if value != default:
keywords[name] = value
else:
if value is not default:
keywords[name] = value
# Work out path - we shorten it for known Django core fields
path = "%s.%s" % (self.__class__.__module__, self.__class__.__name__)
if path.startswith("django.db.models.fields.related"):
path = path.replace("django.db.models.fields.related", "django.db.models")
if path.startswith("django.db.models.fields.files"):
path = path.replace("django.db.models.fields.files", "django.db.models")
if path.startswith("django.db.models.fields"):
path = path.replace("django.db.models.fields", "django.db.models")
# Return basic info - other fields should override this.
return (
self.name,
path,
[],
keywords,
)
def __eq__(self, other):
# Needed for @total_ordering
if isinstance(other, Field):
@ -566,6 +652,7 @@ class Field(object):
return '<%s: %s>' % (path, name)
return '<%s>' % path
class AutoField(Field):
description = _("Integer")
@ -580,6 +667,12 @@ class AutoField(Field):
kwargs['blank'] = True
Field.__init__(self, *args, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(AutoField, self).deconstruct()
del kwargs['blank']
kwargs['primary_key'] = True
return name, path, args, kwargs
def get_internal_type(self):
return "AutoField"
@ -630,6 +723,11 @@ class BooleanField(Field):
kwargs['blank'] = True
Field.__init__(self, *args, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(BooleanField, self).deconstruct()
del kwargs['blank']
return name, path, args, kwargs
def get_internal_type(self):
return "BooleanField"
@ -733,6 +831,18 @@ class DateField(Field):
kwargs['blank'] = True
Field.__init__(self, verbose_name, name, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(DateField, self).deconstruct()
if self.auto_now:
kwargs['auto_now'] = True
del kwargs['editable']
del kwargs['blank']
if self.auto_now_add:
kwargs['auto_now_add'] = True
del kwargs['editable']
del kwargs['blank']
return name, path, args, kwargs
def get_internal_type(self):
return "DateField"
@ -927,6 +1037,14 @@ class DecimalField(Field):
self.max_digits, self.decimal_places = max_digits, decimal_places
Field.__init__(self, verbose_name, name, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(DecimalField, self).deconstruct()
if self.max_digits:
kwargs['max_digits'] = self.max_digits
if self.decimal_places:
kwargs['decimal_places'] = self.decimal_places
return name, path, args, kwargs
def get_internal_type(self):
return "DecimalField"
@ -989,6 +1107,12 @@ class EmailField(CharField):
kwargs['max_length'] = kwargs.get('max_length', 75)
CharField.__init__(self, *args, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(EmailField, self).deconstruct()
# We do not exclude max_length if it matches default as we want to change
# the default in future.
return name, path, args, kwargs
def formfield(self, **kwargs):
# As with CharField, this will cause email validation to be performed
# twice.
@ -1008,6 +1132,22 @@ class FilePathField(Field):
kwargs['max_length'] = kwargs.get('max_length', 100)
Field.__init__(self, verbose_name, name, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(FilePathField, self).deconstruct()
if self.path != '':
kwargs['path'] = self.path
if self.match is not None:
kwargs['match'] = self.match
if self.recursive is not False:
kwargs['recursive'] = self.recursive
if self.allow_files is not True:
kwargs['allow_files'] = self.allow_files
if self.allow_folders is not False:
kwargs['allow_folders'] = self.allow_folders
if kwargs.get("max_length", None) == 100:
del kwargs["max_length"]
return name, path, args, kwargs
def formfield(self, **kwargs):
defaults = {
'path': self.path,
@ -1115,6 +1255,11 @@ class IPAddressField(Field):
kwargs['max_length'] = 15
Field.__init__(self, *args, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(IPAddressField, self).deconstruct()
del kwargs['max_length']
return name, path, args, kwargs
def get_internal_type(self):
return "IPAddressField"
@ -1131,12 +1276,23 @@ class GenericIPAddressField(Field):
def __init__(self, verbose_name=None, name=None, protocol='both',
unpack_ipv4=False, *args, **kwargs):
self.unpack_ipv4 = unpack_ipv4
self.protocol = protocol
self.default_validators, invalid_error_message = \
validators.ip_address_validators(protocol, unpack_ipv4)
self.default_error_messages['invalid'] = invalid_error_message
kwargs['max_length'] = 39
Field.__init__(self, verbose_name, name, *args, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(GenericIPAddressField, self).deconstruct()
if self.unpack_ipv4 is not False:
kwargs['unpack_ipv4'] = self.unpack_ipv4
if self.protocol != "both":
kwargs['protocol'] = self.protocol
if kwargs.get("max_length", None) == 39:
del kwargs['max_length']
return name, path, args, kwargs
def get_internal_type(self):
return "GenericIPAddressField"
@ -1177,6 +1333,12 @@ class NullBooleanField(Field):
kwargs['blank'] = True
Field.__init__(self, *args, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(NullBooleanField, self).deconstruct()
del kwargs['null']
del kwargs['blank']
return name, path, args, kwargs
def get_internal_type(self):
return "NullBooleanField"
@ -1254,6 +1416,16 @@ class SlugField(CharField):
kwargs['db_index'] = True
super(SlugField, self).__init__(*args, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(SlugField, self).deconstruct()
if kwargs.get("max_length", None) == 50:
del kwargs['max_length']
if self.db_index is False:
kwargs['db_index'] = False
else:
del kwargs['db_index']
return name, path, args, kwargs
def get_internal_type(self):
return "SlugField"
@ -1302,6 +1474,14 @@ class TimeField(Field):
kwargs['blank'] = True
Field.__init__(self, verbose_name, name, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(TimeField, self).deconstruct()
if self.auto_now is not False:
kwargs["auto_now"] = self.auto_now
if self.auto_now_add is not False:
kwargs["auto_now_add"] = self.auto_now_add
return name, path, args, kwargs
def get_internal_type(self):
return "TimeField"
@ -1367,6 +1547,12 @@ class URLField(CharField):
kwargs['max_length'] = kwargs.get('max_length', 200)
CharField.__init__(self, verbose_name, name, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(URLField, self).deconstruct()
if kwargs.get("max_length", None) == 200:
del kwargs['max_length']
return name, path, args, kwargs
def formfield(self, **kwargs):
# As with CharField, this will cause URL validation to be performed
# twice.

19
django/db/models/fields/files.py
View File

@ -227,6 +227,17 @@ class FileField(Field):
kwargs['max_length'] = kwargs.get('max_length', 100)
super(FileField, self).__init__(verbose_name, name, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(FileField, self).deconstruct()
if kwargs.get("max_length", None) != 100:
kwargs["max_length"] = 100
else:
del kwargs["max_length"]
kwargs['upload_to'] = self.upload_to
if self.storage is not default_storage:
kwargs['storage'] = self.storage
return name, path, args, kwargs
def get_internal_type(self):
return "FileField"
@ -326,6 +337,14 @@ class ImageField(FileField):
self.width_field, self.height_field = width_field, height_field
super(ImageField, self).__init__(verbose_name, name, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(ImageField, self).deconstruct()
if self.width_field:
kwargs['width_field'] = self.width_field
if self.height_field:
kwargs['height_field'] = self.height_field
return name, path, args, kwargs
def contribute_to_class(self, cls, name):
super(ImageField, self).contribute_to_class(cls, name)
# Attach update_dimension_fields so that dimension fields declared

42
django/db/models/fields/related.py
View File

@ -1151,6 +1151,27 @@ class ForeignKey(ForeignObject):
)
super(ForeignKey, self).__init__(to, ['self'], [to_field], **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(ForeignKey, self).deconstruct()
# Handle the simpler arguments
if self.db_index:
del kwargs['db_index']
else:
kwargs['db_index'] = False
if self.db_constraint is not True:
kwargs['db_constraint'] = self.db_constraint
if self.rel.on_delete is not CASCADE:
kwargs['on_delete'] = self.rel.on_delete
# Rel needs more work.
rel = self.rel
if self.rel.field_name:
kwargs['to_field'] = self.rel.field_name
if isinstance(self.rel.to, basestring):
kwargs['to'] = self.rel.to
else:
kwargs['to'] = "%s.%s" % (self.rel.to._meta.app_label, self.rel.to._meta.object_name)
return name, path, args, kwargs
@property
def related_field(self):
return self.foreign_related_fields[0]
@ -1268,6 +1289,12 @@ class OneToOneField(ForeignKey):
kwargs['unique'] = True
super(OneToOneField, self).__init__(to, to_field, OneToOneRel, **kwargs)
def deconstruct(self):
name, path, args, kwargs = super(OneToOneField, self).deconstruct()
if "unique" in kwargs:
del kwargs['unique']
return name, path, args, kwargs
def contribute_to_related_class(self, cls, related):
setattr(cls, related.get_accessor_name(),
SingleRelatedObjectDescriptor(related))
@ -1357,6 +1384,21 @@ class ManyToManyField(RelatedField):
super(ManyToManyField, self).__init__(**kwargs)
def deconstruct(self):
name, path, args, kwargs = super(ManyToManyField, self).deconstruct()
# Handle the simpler arguments
if self.rel.db_constraint is not True:
kwargs['db_constraint'] = self.db_constraint
if "help_text" in kwargs:
del kwargs['help_text']
# Rel needs more work.
rel = self.rel
if isinstance(self.rel.to, basestring):
kwargs['to'] = self.rel.to
else:
kwargs['to'] = "%s.%s" % (self.rel.to._meta.app_label, self.rel.to._meta.object_name)
return name, path, args, kwargs
def _get_path_info(self, direct=False):
"""
Called by both direct an indirect m2m traversal.

0
tests/field_deconstruction/__init__.py Normal file
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0
tests/field_deconstruction/models.py Normal file
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253
tests/field_deconstruction/tests.py Normal file
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@ -0,0 +1,253 @@
from django.test import TestCase
from django.db import models
class FieldDeconstructionTests(TestCase):
"""
Tests the deconstruct() method on all core fields.
"""
def test_name(self):
"""
Tests the outputting of the correct name if assigned one.
"""
# First try using a "normal" field
field = models.CharField(max_length=65)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(name, None)
field.set_attributes_from_name("is_awesome_test")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(name, "is_awesome_test")
# Now try with a ForeignKey
field = models.ForeignKey("some_fake.ModelName")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(name, None)
field.set_attributes_from_name("author")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(name, "author")
def test_auto_field(self):
field = models.AutoField(primary_key=True)
field.set_attributes_from_name("id")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.AutoField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"primary_key": True})
def test_big_integer_field(self):
field = models.BigIntegerField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.BigIntegerField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_boolean_field(self):
field = models.BooleanField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.BooleanField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
field = models.BooleanField(default=True)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.BooleanField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"default": True})
def test_char_field(self):
field = models.CharField(max_length=65)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.CharField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"max_length": 65})
field = models.CharField(max_length=65, null=True, blank=True)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.CharField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"max_length": 65, "null": True, "blank": True})
def test_csi_field(self):
field = models.CommaSeparatedIntegerField(max_length=100)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.CommaSeparatedIntegerField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"max_length": 100})
def test_date_field(self):
field = models.DateField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.DateField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
field = models.DateField(auto_now=True)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.DateField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"auto_now": True})
def test_datetime_field(self):
field = models.DateTimeField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.DateTimeField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
field = models.DateTimeField(auto_now_add=True)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.DateTimeField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"auto_now_add": True})
def test_decimal_field(self):
field = models.DecimalField(max_digits=5, decimal_places=2)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.DecimalField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"max_digits": 5, "decimal_places": 2})
def test_email_field(self):
field = models.EmailField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.EmailField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"max_length": 75})
field = models.EmailField(max_length=255)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.EmailField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"max_length": 255})
def test_file_field(self):
field = models.FileField(upload_to="foo/bar")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.FileField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"upload_to": "foo/bar"})
def test_file_path_field(self):
field = models.FilePathField(match=".*\.txt$")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.FilePathField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"match": ".*\.txt$"})
field = models.FilePathField(recursive=True, allow_folders=True)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.FilePathField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"recursive": True, "allow_folders": True})
def test_float_field(self):
field = models.FloatField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.FloatField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_foreign_key(self):
field = models.ForeignKey("auth.User")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.ForeignKey")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"to": "auth.User"})
field = models.ForeignKey("something.Else")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.ForeignKey")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"to": "something.Else"})
field = models.ForeignKey("auth.User", on_delete=models.SET_NULL)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.ForeignKey")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"to": "auth.User", "on_delete": models.SET_NULL})
def test_image_field(self):
field = models.ImageField(upload_to="foo/barness", width_field="width", height_field="height")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.ImageField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"upload_to": "foo/barness", "width_field": "width", "height_field": "height"})
def test_integer_field(self):
field = models.IntegerField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.IntegerField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_ip_address_field(self):
field = models.IPAddressField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.IPAddressField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_generic_ip_address_field(self):
field = models.GenericIPAddressField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.GenericIPAddressField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
field = models.GenericIPAddressField(protocol="IPv6")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.GenericIPAddressField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"protocol": "IPv6"})
def test_many_to_many_field(self):
field = models.ManyToManyField("auth.User")
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.ManyToManyField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"to": "auth.User"})
def test_null_boolean_field(self):
field = models.NullBooleanField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.NullBooleanField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_positive_integer_field(self):
field = models.PositiveIntegerField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.PositiveIntegerField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_positive_small_integer_field(self):
field = models.PositiveSmallIntegerField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.PositiveSmallIntegerField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_slug_field(self):
field = models.SlugField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.SlugField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
field = models.SlugField(db_index=False)
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.SlugField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {"db_index": False})
def test_small_integer_field(self):
field = models.SmallIntegerField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.SmallIntegerField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_text_field(self):
field = models.TextField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.TextField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})
def test_url_field(self):
field = models.URLField()
name, path, args, kwargs = field.deconstruct()
self.assertEqual(path, "django.db.models.URLField")
self.assertEqual(args, [])
self.assertEqual(kwargs, {})