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