import builtins
import collections
import datetime
import decimal
import enum
import functools
import math
import re
import types
import uuid
from django.db import models
from django.db.migrations.operations.base import Operation
from django.db.migrations.utils import COMPILED_REGEX_TYPE, RegexObject
from django.utils import datetime_safe
from django.utils.functional import LazyObject, Promise
from django.utils.timezone import utc
from django.utils.version import get_docs_version
class BaseSerializer:
def __init__(self, value):
self.value = value
def serialize(self):
raise NotImplementedError('Subclasses of BaseSerializer must implement the serialize() method.')
class BaseSequenceSerializer(BaseSerializer):
def _format(self):
raise NotImplementedError('Subclasses of BaseSequenceSerializer must implement the _format() method.')
def serialize(self):
imports = set()
strings = []
for item in self.value:
item_string, item_imports = serializer_factory(item).serialize()
imports.update(item_imports)
strings.append(item_string)
value = self._format()
return value % (", ".join(strings)), imports
class BaseSimpleSerializer(BaseSerializer):
def serialize(self):
return repr(self.value), set()
class ByteTypeSerializer(BaseSerializer):
def serialize(self):
return repr(self.value), set()
class DatetimeSerializer(BaseSerializer):
def serialize(self):
if self.value.tzinfo is not None and self.value.tzinfo != utc:
self.value = self.value.astimezone(utc)
value_repr = repr(self.value).replace("<UTC>", "utc")
if isinstance(self.value, datetime_safe.datetime):
value_repr = "datetime.%s" % value_repr
imports = ["import datetime"]
if self.value.tzinfo is not None:
imports.append("from django.utils.timezone import utc")
return value_repr, set(imports)
class DateSerializer(BaseSerializer):
def serialize(self):
value_repr = repr(self.value)
if isinstance(self.value, datetime_safe.date):
value_repr = "datetime.%s" % value_repr
return value_repr, {"import datetime"}
class DecimalSerializer(BaseSerializer):
def serialize(self):
return repr(self.value), {"from decimal import Decimal"}
class DeconstructableSerializer(BaseSerializer):
@staticmethod
def serialize_deconstructed(path, args, kwargs):
name, imports = DeconstructableSerializer._serialize_path(path)
strings = []
for arg in args:
arg_string, arg_imports = serializer_factory(arg).serialize()
strings.append(arg_string)
imports.update(arg_imports)
for kw, arg in sorted(kwargs.items()):
arg_string, arg_imports = serializer_factory(arg).serialize()
imports.update(arg_imports)
strings.append("%s=%s" % (kw, arg_string))
return "%s(%s)" % (name, ", ".join(strings)), imports
@staticmethod
def _serialize_path(path):
module, name = path.rsplit(".", 1)
if module == "django.db.models":
imports = {"from django.db import models"}
name = "models.%s" % name
else:
imports = {"import %s" % module}
name = path
return name, imports
def serialize(self):
return self.serialize_deconstructed(*self.value.deconstruct())
class DictionarySerializer(BaseSerializer):
def serialize(self):
imports = set()
strings = []
for k, v in sorted(self.value.items()):
k_string, k_imports = serializer_factory(k).serialize()
v_string, v_imports = serializer_factory(v).serialize()
imports.update(k_imports)
imports.update(v_imports)
strings.append((k_string, v_string))
return "{%s}" % (", ".join("%s: %s" % (k, v) for k, v in strings)), imports
class EnumSerializer(BaseSerializer):
def serialize(self):
enum_class = self.value.__class__
module = enum_class.__module__
imports = {"import %s" % module}
v_string, v_imports = serializer_factory(self.value.value).serialize()
imports.update(v_imports)
return "%s.%s(%s)" % (module, enum_class.__name__, v_string), imports
class FloatSerializer(BaseSimpleSerializer):
def serialize(self):
if math.isnan(self.value) or math.isinf(self.value):
return 'float("{}")'.format(self.value), set()
return super().serialize()
class FrozensetSerializer(BaseSequenceSerializer):
def _format(self):
return "frozenset([%s])"
class FunctionTypeSerializer(BaseSerializer):
def serialize(self):
if getattr(self.value, "__self__", None) and isinstance(self.value.__self__, type):
klass = self.value.__self__
module = klass.__module__
return "%s.%s.%s" % (module, klass.__name__, self.value.__name__), {"import %s" % module}
# Further error checking
if self.value.__name__ == '<lambda>':
raise ValueError("Cannot serialize function: lambda")
if self.value.__module__ is None:
raise ValueError("Cannot serialize function %r: No module" % self.value)
module_name = self.value.__module__
if '<' not in self.value.__qualname__: # Qualname can include <locals>
return '%s.%s' % (module_name, self.value.__qualname__), {'import %s' % self.value.__module__}
raise ValueError(
'Could not find function %s in %s.\n' % (self.value.__name__, module_name)
)
class FunctoolsPartialSerializer(BaseSerializer):
def serialize(self):
imports = {'import functools'}
# Serialize functools.partial() arguments
func_string, func_imports = serializer_factory(self.value.func).serialize()
args_string, args_imports = serializer_factory(self.value.args).serialize()
keywords_string, keywords_imports = serializer_factory(self.value.keywords).serialize()
# Add any imports needed by arguments
imports.update(func_imports)
imports.update(args_imports)
imports.update(keywords_imports)
return (
"functools.partial(%s, *%s, **%s)" % (
func_string, args_string, keywords_string,
),
imports,
)
class IterableSerializer(BaseSerializer):
def serialize(self):
imports = set()
strings = []
for item in self.value:
item_string, item_imports = serializer_factory(item).serialize()
imports.update(item_imports)
strings.append(item_string)
# When len(strings)==0, the empty iterable should be serialized as
# "()", not "(,)" because (,) is invalid Python syntax.
value = "(%s)" if len(strings) != 1 else "(%s,)"
return value % (", ".join(strings)), imports
class ModelFieldSerializer(DeconstructableSerializer):
def serialize(self):
attr_name, path, args, kwargs = self.value.deconstruct()
return self.serialize_deconstructed(path, args, kwargs)
class ModelManagerSerializer(DeconstructableSerializer):
def serialize(self):
as_manager, manager_path, qs_path, args, kwargs = self.value.deconstruct()
if as_manager:
name, imports = self._serialize_path(qs_path)
return "%s.as_manager()" % name, imports
else:
return self.serialize_deconstructed(manager_path, args, kwargs)
class OperationSerializer(BaseSerializer):
def serialize(self):
from django.db.migrations.writer import OperationWriter
string, imports = OperationWriter(self.value, indentation=0).serialize()
# Nested operation, trailing comma is handled in upper OperationWriter._write()
return string.rstrip(','), imports
class RegexSerializer(BaseSerializer):
def serialize(self):
imports = {"import re"}
regex_pattern, pattern_imports = serializer_factory(self.value.pattern).serialize()
# Turn off default implicit flags (e.g. re.U) because regexes with the
# same implicit and explicit flags aren't equal.
flags = self.value.flags ^ re.compile('').flags
regex_flags, flag_imports = serializer_factory(flags).serialize()
imports.update(pattern_imports)
imports.update(flag_imports)
args = [regex_pattern]
if flags:
args.append(regex_flags)
return "re.compile(%s)" % ', '.join(args), imports
class SequenceSerializer(BaseSequenceSerializer):
def _format(self):
return "[%s]"
class SetSerializer(BaseSequenceSerializer):
def _format(self):
# Serialize as a set literal except when value is empty because {}
# is an empty dict.
return '{%s}' if self.value else 'set(%s)'
class SettingsReferenceSerializer(BaseSerializer):
def serialize(self):
return "settings.%s" % self.value.setting_name, {"from django.conf import settings"}
class TextTypeSerializer(BaseSerializer):
def serialize(self):
return repr(self.value), set()
class TimedeltaSerializer(BaseSerializer):
def serialize(self):
return repr(self.value), {"import datetime"}
class TimeSerializer(BaseSerializer):
def serialize(self):
value_repr = repr(self.value)
if isinstance(self.value, datetime_safe.time):
value_repr = "datetime.%s" % value_repr
return value_repr, {"import datetime"}
class TupleSerializer(BaseSequenceSerializer):
def _format(self):
# When len(value)==0, the empty tuple should be serialized as "()",
# not "(,)" because (,) is invalid Python syntax.
return "(%s)" if len(self.value) != 1 else "(%s,)"
class TypeSerializer(BaseSerializer):
def serialize(self):
special_cases = [
(models.Model, "models.Model", []),
]
for case, string, imports in special_cases:
if case is self.value:
return string, set(imports)
if hasattr(self.value, "__module__"):
module = self.value.__module__
if module == builtins.__name__:
return self.value.__name__, set()
else:
return "%s.%s" % (module, self.value.__name__), {"import %s" % module}
class UUIDSerializer(BaseSerializer):
def serialize(self):
return "uuid.%s" % repr(self.value), {"import uuid"}
def serializer_factory(value):
from django.db.migrations.writer import SettingsReference
if isinstance(value, Promise):
value = str(value)
elif isinstance(value, LazyObject):
# The unwrapped value is returned as the first item of the arguments
# tuple.
value = value.__reduce__()[1][0]
if isinstance(value, models.Field):
return ModelFieldSerializer(value)
if isinstance(value, models.manager.BaseManager):
return ModelManagerSerializer(value)
if isinstance(value, Operation):
return OperationSerializer(value)
if isinstance(value, type):
return TypeSerializer(value)
# Anything that knows how to deconstruct itself.
if hasattr(value, 'deconstruct'):
return DeconstructableSerializer(value)
# Unfortunately some of these are order-dependent.
if isinstance(value, frozenset):
return FrozensetSerializer(value)
if isinstance(value, list):
return SequenceSerializer(value)
if isinstance(value, set):
return SetSerializer(value)
if isinstance(value, tuple):
return TupleSerializer(value)
if isinstance(value, dict):
return DictionarySerializer(value)
if isinstance(value, enum.Enum):
return EnumSerializer(value)
if isinstance(value, datetime.datetime):
return DatetimeSerializer(value)
if isinstance(value, datetime.date):
return DateSerializer(value)
if isinstance(value, datetime.time):
return TimeSerializer(value)
if isinstance(value, datetime.timedelta):
return TimedeltaSerializer(value)
if isinstance(value, SettingsReference):
return SettingsReferenceSerializer(value)
if isinstance(value, float):
return FloatSerializer(value)
if isinstance(value, (bool, int, type(None))):
return BaseSimpleSerializer(value)
if isinstance(value, bytes):
return ByteTypeSerializer(value)
if isinstance(value, str):
return TextTypeSerializer(value)
if isinstance(value, decimal.Decimal):
return DecimalSerializer(value)
if isinstance(value, functools.partial):
return FunctoolsPartialSerializer(value)
if isinstance(value, (types.FunctionType, types.BuiltinFunctionType, types.MethodType)):
return FunctionTypeSerializer(value)
if isinstance(value, collections.Iterable):
return IterableSerializer(value)
if isinstance(value, (COMPILED_REGEX_TYPE, RegexObject)):
return RegexSerializer(value)
if isinstance(value, uuid.UUID):
return UUIDSerializer(value)
raise ValueError(
"Cannot serialize: %r\nThere are some values Django cannot serialize into "
"migration files.\nFor more, see https://docs.djangoproject.com/en/%s/"
"topics/migrations/#migration-serializing" % (value, get_docs_version())
)