Add a deconstruct() method to Fields. (028bbd15) · Commits · Dom Sekotill / django

django/db/models/fields/init.py

+187 −1

Original line number	Diff line number	Diff line
		@@ -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):
		@@ -584,6 +670,7 @@ class Field(object):
		return '<%s: %s>' % (path, name)
		return '<%s>' % path


		class AutoField(Field):
		description = _("Integer")

		@@ -598,6 +685,12 @@ 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"

		@@ -645,6 +738,11 @@ 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"

		@@ -745,6 +843,18 @@ 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"

		@@ -924,6 +1034,14 @@ 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"

		@@ -983,6 +1101,12 @@ 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()
		if kwargs.get("max_length", None) == 75:
		del kwargs['max_length']
		return name, path, args, kwargs

		def formfield(self, **kwargs):
		# As with CharField, this will cause email validation to be performed
		# twice.
		@@ -1002,6 +1126,22 @@ 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,
		@@ -1103,6 +1243,11 @@ 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"

		@@ -1119,12 +1264,23 @@ 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"

		@@ -1165,6 +1321,12 @@ 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"

		@@ -1238,6 +1400,16 @@ 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"

		@@ -1286,6 +1458,14 @@ 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"

		@@ -1345,6 +1525,12 @@ class URLField(CharField):
		CharField.__init__(self, verbose_name, name, **kwargs)
		self.validators.append(validators.URLValidator())

		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.

django/db/models/fields/files.py

+19 −0

Original line number	Diff line number	Diff line
		@@ -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

django/db/models/fields/related.py

+41 −0

Original line number	Diff line number	Diff line
		@@ -1146,6 +1146,27 @@ 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]
		@@ -1263,6 +1284,12 @@ 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))
		@@ -1355,6 +1382,20 @@ class ManyToManyField(RelatedField):
		msg = _('Hold down "Control", or "Command" on a Mac, to select more than one.')
		self.help_text = string_concat(self.help_text, ' ', msg)

		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
		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.

tests/field_deconstruction/init.py

0 → 100644

+0 −0

Empty file added.

tests/field_deconstruction/models.py

0 → 100644

+0 −0

Empty file added.