989 lines
37 KiB
Python
989 lines
37 KiB
Python
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import bisect
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import copy
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import inspect
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from collections import defaultdict
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from django.apps import apps
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from django.conf import settings
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from django.core.exceptions import FieldDoesNotExist, ImproperlyConfigured
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from django.db import connections
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from django.db.models import AutoField, Manager, OrderWrt, UniqueConstraint
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from django.db.models.query_utils import PathInfo
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from django.utils.datastructures import ImmutableList, OrderedSet
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from django.utils.functional import cached_property
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from django.utils.module_loading import import_string
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from django.utils.text import camel_case_to_spaces, format_lazy
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from django.utils.translation import override
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PROXY_PARENTS = object()
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EMPTY_RELATION_TREE = ()
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IMMUTABLE_WARNING = (
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"The return type of '%s' should never be mutated. If you want to manipulate this "
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"list for your own use, make a copy first."
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)
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DEFAULT_NAMES = (
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"verbose_name",
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"verbose_name_plural",
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"db_table",
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"ordering",
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"unique_together",
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"permissions",
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"get_latest_by",
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"order_with_respect_to",
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"app_label",
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"db_tablespace",
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"abstract",
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"managed",
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"proxy",
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"swappable",
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"auto_created",
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"index_together",
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"apps",
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"default_permissions",
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"select_on_save",
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"default_related_name",
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"required_db_features",
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"required_db_vendor",
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"base_manager_name",
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"default_manager_name",
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"indexes",
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"constraints",
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)
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def normalize_together(option_together):
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"""
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option_together can be either a tuple of tuples, or a single
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tuple of two strings. Normalize it to a tuple of tuples, so that
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calling code can uniformly expect that.
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"""
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try:
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if not option_together:
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return ()
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if not isinstance(option_together, (tuple, list)):
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raise TypeError
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first_element = option_together[0]
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if not isinstance(first_element, (tuple, list)):
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option_together = (option_together,)
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# Normalize everything to tuples
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return tuple(tuple(ot) for ot in option_together)
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except TypeError:
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# If the value of option_together isn't valid, return it
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# verbatim; this will be picked up by the check framework later.
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return option_together
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def make_immutable_fields_list(name, data):
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return ImmutableList(data, warning=IMMUTABLE_WARNING % name)
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class Options:
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FORWARD_PROPERTIES = {
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"fields",
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"many_to_many",
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"concrete_fields",
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"local_concrete_fields",
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"_forward_fields_map",
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"managers",
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"managers_map",
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"base_manager",
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"default_manager",
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}
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REVERSE_PROPERTIES = {"related_objects", "fields_map", "_relation_tree"}
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default_apps = apps
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def __init__(self, meta, app_label=None):
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self._get_fields_cache = {}
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self.local_fields = []
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self.local_many_to_many = []
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self.private_fields = []
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self.local_managers = []
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self.base_manager_name = None
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self.default_manager_name = None
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self.model_name = None
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self.verbose_name = None
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self.verbose_name_plural = None
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self.db_table = ""
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self.ordering = []
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self._ordering_clash = False
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self.indexes = []
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self.constraints = []
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self.unique_together = []
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self.index_together = []
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self.select_on_save = False
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self.default_permissions = ("add", "change", "delete", "view")
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self.permissions = []
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self.object_name = None
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self.app_label = app_label
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self.get_latest_by = None
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self.order_with_respect_to = None
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self.db_tablespace = settings.DEFAULT_TABLESPACE
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self.required_db_features = []
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self.required_db_vendor = None
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self.meta = meta
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self.pk = None
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self.auto_field = None
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self.abstract = False
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self.managed = True
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self.proxy = False
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# For any class that is a proxy (including automatically created
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# classes for deferred object loading), proxy_for_model tells us
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# which class this model is proxying. Note that proxy_for_model
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# can create a chain of proxy models. For non-proxy models, the
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# variable is always None.
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self.proxy_for_model = None
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# For any non-abstract class, the concrete class is the model
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# in the end of the proxy_for_model chain. In particular, for
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# concrete models, the concrete_model is always the class itself.
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self.concrete_model = None
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self.swappable = None
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self.parents = {}
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self.auto_created = False
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# List of all lookups defined in ForeignKey 'limit_choices_to' options
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# from *other* models. Needed for some admin checks. Internal use only.
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self.related_fkey_lookups = []
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# A custom app registry to use, if you're making a separate model set.
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self.apps = self.default_apps
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self.default_related_name = None
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@property
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def label(self):
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return "%s.%s" % (self.app_label, self.object_name)
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@property
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def label_lower(self):
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return "%s.%s" % (self.app_label, self.model_name)
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@property
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def app_config(self):
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# Don't go through get_app_config to avoid triggering imports.
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return self.apps.app_configs.get(self.app_label)
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def contribute_to_class(self, cls, name):
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from django.db import connection
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from django.db.backends.utils import truncate_name
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cls._meta = self
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self.model = cls
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# First, construct the default values for these options.
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self.object_name = cls.__name__
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self.model_name = self.object_name.lower()
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self.verbose_name = camel_case_to_spaces(self.object_name)
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# Store the original user-defined values for each option,
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# for use when serializing the model definition
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self.original_attrs = {}
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# Next, apply any overridden values from 'class Meta'.
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if self.meta:
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meta_attrs = self.meta.__dict__.copy()
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for name in self.meta.__dict__:
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# Ignore any private attributes that Django doesn't care about.
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# NOTE: We can't modify a dictionary's contents while looping
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# over it, so we loop over the *original* dictionary instead.
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if name.startswith("_"):
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del meta_attrs[name]
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for attr_name in DEFAULT_NAMES:
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if attr_name in meta_attrs:
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setattr(self, attr_name, meta_attrs.pop(attr_name))
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self.original_attrs[attr_name] = getattr(self, attr_name)
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elif hasattr(self.meta, attr_name):
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setattr(self, attr_name, getattr(self.meta, attr_name))
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self.original_attrs[attr_name] = getattr(self, attr_name)
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self.unique_together = normalize_together(self.unique_together)
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self.index_together = normalize_together(self.index_together)
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# App label/class name interpolation for names of constraints and
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# indexes.
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if not getattr(cls._meta, "abstract", False):
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for attr_name in {"constraints", "indexes"}:
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objs = getattr(self, attr_name, [])
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setattr(self, attr_name, self._format_names_with_class(cls, objs))
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# verbose_name_plural is a special case because it uses a 's'
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# by default.
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if self.verbose_name_plural is None:
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self.verbose_name_plural = format_lazy("{}s", self.verbose_name)
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# order_with_respect_and ordering are mutually exclusive.
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self._ordering_clash = bool(self.ordering and self.order_with_respect_to)
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# Any leftover attributes must be invalid.
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if meta_attrs != {}:
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raise TypeError(
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"'class Meta' got invalid attribute(s): %s" % ",".join(meta_attrs)
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)
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else:
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self.verbose_name_plural = format_lazy("{}s", self.verbose_name)
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del self.meta
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# If the db_table wasn't provided, use the app_label + model_name.
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if not self.db_table:
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self.db_table = "%s_%s" % (self.app_label, self.model_name)
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self.db_table = truncate_name(
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self.db_table, connection.ops.max_name_length()
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)
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def _format_names_with_class(self, cls, objs):
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"""App label/class name interpolation for object names."""
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new_objs = []
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for obj in objs:
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obj = obj.clone()
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obj.name = obj.name % {
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"app_label": cls._meta.app_label.lower(),
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"class": cls.__name__.lower(),
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}
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new_objs.append(obj)
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return new_objs
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def _get_default_pk_class(self):
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pk_class_path = getattr(
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self.app_config,
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"default_auto_field",
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settings.DEFAULT_AUTO_FIELD,
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)
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if self.app_config and self.app_config._is_default_auto_field_overridden:
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app_config_class = type(self.app_config)
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source = (
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f"{app_config_class.__module__}."
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f"{app_config_class.__qualname__}.default_auto_field"
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)
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else:
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source = "DEFAULT_AUTO_FIELD"
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if not pk_class_path:
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raise ImproperlyConfigured(f"{source} must not be empty.")
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try:
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pk_class = import_string(pk_class_path)
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except ImportError as e:
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msg = (
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f"{source} refers to the module '{pk_class_path}' that could "
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f"not be imported."
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)
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raise ImproperlyConfigured(msg) from e
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if not issubclass(pk_class, AutoField):
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raise ValueError(
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f"Primary key '{pk_class_path}' referred by {source} must "
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f"subclass AutoField."
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)
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return pk_class
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def _prepare(self, model):
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if self.order_with_respect_to:
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# The app registry will not be ready at this point, so we cannot
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# use get_field().
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query = self.order_with_respect_to
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try:
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self.order_with_respect_to = next(
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f
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for f in self._get_fields(reverse=False)
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if f.name == query or f.attname == query
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)
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except StopIteration:
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raise FieldDoesNotExist(
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"%s has no field named '%s'" % (self.object_name, query)
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)
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self.ordering = ("_order",)
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if not any(
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isinstance(field, OrderWrt) for field in model._meta.local_fields
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):
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model.add_to_class("_order", OrderWrt())
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else:
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self.order_with_respect_to = None
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if self.pk is None:
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if self.parents:
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# Promote the first parent link in lieu of adding yet another
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# field.
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field = next(iter(self.parents.values()))
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# Look for a local field with the same name as the
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# first parent link. If a local field has already been
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# created, use it instead of promoting the parent
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already_created = [
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fld for fld in self.local_fields if fld.name == field.name
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]
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if already_created:
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field = already_created[0]
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field.primary_key = True
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self.setup_pk(field)
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else:
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pk_class = self._get_default_pk_class()
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auto = pk_class(verbose_name="ID", primary_key=True, auto_created=True)
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model.add_to_class("id", auto)
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def add_manager(self, manager):
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self.local_managers.append(manager)
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self._expire_cache()
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def add_field(self, field, private=False):
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# Insert the given field in the order in which it was created, using
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# the "creation_counter" attribute of the field.
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# Move many-to-many related fields from self.fields into
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# self.many_to_many.
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if private:
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self.private_fields.append(field)
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elif field.is_relation and field.many_to_many:
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bisect.insort(self.local_many_to_many, field)
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else:
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bisect.insort(self.local_fields, field)
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self.setup_pk(field)
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# If the field being added is a relation to another known field,
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# expire the cache on this field and the forward cache on the field
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# being referenced, because there will be new relationships in the
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# cache. Otherwise, expire the cache of references *to* this field.
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# The mechanism for getting at the related model is slightly odd -
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# ideally, we'd just ask for field.related_model. However, related_model
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# is a cached property, and all the models haven't been loaded yet, so
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# we need to make sure we don't cache a string reference.
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if (
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field.is_relation
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and hasattr(field.remote_field, "model")
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and field.remote_field.model
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):
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try:
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field.remote_field.model._meta._expire_cache(forward=False)
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except AttributeError:
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pass
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self._expire_cache()
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else:
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self._expire_cache(reverse=False)
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def setup_pk(self, field):
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if not self.pk and field.primary_key:
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self.pk = field
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field.serialize = False
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def setup_proxy(self, target):
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"""
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Do the internal setup so that the current model is a proxy for
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"target".
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"""
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||
|
|
self.pk = target._meta.pk
|
||
|
|
self.proxy_for_model = target
|
||
|
|
self.db_table = target._meta.db_table
|
||
|
|
|
||
|
|
def __repr__(self):
|
||
|
|
return "<Options for %s>" % self.object_name
|
||
|
|
|
||
|
|
def __str__(self):
|
||
|
|
return self.label_lower
|
||
|
|
|
||
|
|
def can_migrate(self, connection):
|
||
|
|
"""
|
||
|
|
Return True if the model can/should be migrated on the `connection`.
|
||
|
|
`connection` can be either a real connection or a connection alias.
|
||
|
|
"""
|
||
|
|
if self.proxy or self.swapped or not self.managed:
|
||
|
|
return False
|
||
|
|
if isinstance(connection, str):
|
||
|
|
connection = connections[connection]
|
||
|
|
if self.required_db_vendor:
|
||
|
|
return self.required_db_vendor == connection.vendor
|
||
|
|
if self.required_db_features:
|
||
|
|
return all(
|
||
|
|
getattr(connection.features, feat, False)
|
||
|
|
for feat in self.required_db_features
|
||
|
|
)
|
||
|
|
return True
|
||
|
|
|
||
|
|
@property
|
||
|
|
def verbose_name_raw(self):
|
||
|
|
"""Return the untranslated verbose name."""
|
||
|
|
with override(None):
|
||
|
|
return str(self.verbose_name)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def swapped(self):
|
||
|
|
"""
|
||
|
|
Has this model been swapped out for another? If so, return the model
|
||
|
|
name of the replacement; otherwise, return None.
|
||
|
|
|
||
|
|
For historical reasons, model name lookups using get_model() are
|
||
|
|
case insensitive, so we make sure we are case insensitive here.
|
||
|
|
"""
|
||
|
|
if self.swappable:
|
||
|
|
swapped_for = getattr(settings, self.swappable, None)
|
||
|
|
if swapped_for:
|
||
|
|
try:
|
||
|
|
swapped_label, swapped_object = swapped_for.split(".")
|
||
|
|
except ValueError:
|
||
|
|
# setting not in the format app_label.model_name
|
||
|
|
# raising ImproperlyConfigured here causes problems with
|
||
|
|
# test cleanup code - instead it is raised in get_user_model
|
||
|
|
# or as part of validation.
|
||
|
|
return swapped_for
|
||
|
|
|
||
|
|
if (
|
||
|
|
"%s.%s" % (swapped_label, swapped_object.lower())
|
||
|
|
!= self.label_lower
|
||
|
|
):
|
||
|
|
return swapped_for
|
||
|
|
return None
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def managers(self):
|
||
|
|
managers = []
|
||
|
|
seen_managers = set()
|
||
|
|
bases = (b for b in self.model.mro() if hasattr(b, "_meta"))
|
||
|
|
for depth, base in enumerate(bases):
|
||
|
|
for manager in base._meta.local_managers:
|
||
|
|
if manager.name in seen_managers:
|
||
|
|
continue
|
||
|
|
|
||
|
|
manager = copy.copy(manager)
|
||
|
|
manager.model = self.model
|
||
|
|
seen_managers.add(manager.name)
|
||
|
|
managers.append((depth, manager.creation_counter, manager))
|
||
|
|
|
||
|
|
return make_immutable_fields_list(
|
||
|
|
"managers",
|
||
|
|
(m[2] for m in sorted(managers)),
|
||
|
|
)
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def managers_map(self):
|
||
|
|
return {manager.name: manager for manager in self.managers}
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def base_manager(self):
|
||
|
|
base_manager_name = self.base_manager_name
|
||
|
|
if not base_manager_name:
|
||
|
|
# Get the first parent's base_manager_name if there's one.
|
||
|
|
for parent in self.model.mro()[1:]:
|
||
|
|
if hasattr(parent, "_meta"):
|
||
|
|
if parent._base_manager.name != "_base_manager":
|
||
|
|
base_manager_name = parent._base_manager.name
|
||
|
|
break
|
||
|
|
|
||
|
|
if base_manager_name:
|
||
|
|
try:
|
||
|
|
return self.managers_map[base_manager_name]
|
||
|
|
except KeyError:
|
||
|
|
raise ValueError(
|
||
|
|
"%s has no manager named %r"
|
||
|
|
% (
|
||
|
|
self.object_name,
|
||
|
|
base_manager_name,
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
manager = Manager()
|
||
|
|
manager.name = "_base_manager"
|
||
|
|
manager.model = self.model
|
||
|
|
manager.auto_created = True
|
||
|
|
return manager
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def default_manager(self):
|
||
|
|
default_manager_name = self.default_manager_name
|
||
|
|
if not default_manager_name and not self.local_managers:
|
||
|
|
# Get the first parent's default_manager_name if there's one.
|
||
|
|
for parent in self.model.mro()[1:]:
|
||
|
|
if hasattr(parent, "_meta"):
|
||
|
|
default_manager_name = parent._meta.default_manager_name
|
||
|
|
break
|
||
|
|
|
||
|
|
if default_manager_name:
|
||
|
|
try:
|
||
|
|
return self.managers_map[default_manager_name]
|
||
|
|
except KeyError:
|
||
|
|
raise ValueError(
|
||
|
|
"%s has no manager named %r"
|
||
|
|
% (
|
||
|
|
self.object_name,
|
||
|
|
default_manager_name,
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
if self.managers:
|
||
|
|
return self.managers[0]
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def fields(self):
|
||
|
|
"""
|
||
|
|
Return a list of all forward fields on the model and its parents,
|
||
|
|
excluding ManyToManyFields.
|
||
|
|
|
||
|
|
Private API intended only to be used by Django itself; get_fields()
|
||
|
|
combined with filtering of field properties is the public API for
|
||
|
|
obtaining this field list.
|
||
|
|
"""
|
||
|
|
# For legacy reasons, the fields property should only contain forward
|
||
|
|
# fields that are not private or with a m2m cardinality. Therefore we
|
||
|
|
# pass these three filters as filters to the generator.
|
||
|
|
# The third lambda is a longwinded way of checking f.related_model - we don't
|
||
|
|
# use that property directly because related_model is a cached property,
|
||
|
|
# and all the models may not have been loaded yet; we don't want to cache
|
||
|
|
# the string reference to the related_model.
|
||
|
|
def is_not_an_m2m_field(f):
|
||
|
|
return not (f.is_relation and f.many_to_many)
|
||
|
|
|
||
|
|
def is_not_a_generic_relation(f):
|
||
|
|
return not (f.is_relation and f.one_to_many)
|
||
|
|
|
||
|
|
def is_not_a_generic_foreign_key(f):
|
||
|
|
return not (
|
||
|
|
f.is_relation
|
||
|
|
and f.many_to_one
|
||
|
|
and not (hasattr(f.remote_field, "model") and f.remote_field.model)
|
||
|
|
)
|
||
|
|
|
||
|
|
return make_immutable_fields_list(
|
||
|
|
"fields",
|
||
|
|
(
|
||
|
|
f
|
||
|
|
for f in self._get_fields(reverse=False)
|
||
|
|
if is_not_an_m2m_field(f)
|
||
|
|
and is_not_a_generic_relation(f)
|
||
|
|
and is_not_a_generic_foreign_key(f)
|
||
|
|
),
|
||
|
|
)
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def concrete_fields(self):
|
||
|
|
"""
|
||
|
|
Return a list of all concrete fields on the model and its parents.
|
||
|
|
|
||
|
|
Private API intended only to be used by Django itself; get_fields()
|
||
|
|
combined with filtering of field properties is the public API for
|
||
|
|
obtaining this field list.
|
||
|
|
"""
|
||
|
|
return make_immutable_fields_list(
|
||
|
|
"concrete_fields", (f for f in self.fields if f.concrete)
|
||
|
|
)
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def local_concrete_fields(self):
|
||
|
|
"""
|
||
|
|
Return a list of all concrete fields on the model.
|
||
|
|
|
||
|
|
Private API intended only to be used by Django itself; get_fields()
|
||
|
|
combined with filtering of field properties is the public API for
|
||
|
|
obtaining this field list.
|
||
|
|
"""
|
||
|
|
return make_immutable_fields_list(
|
||
|
|
"local_concrete_fields", (f for f in self.local_fields if f.concrete)
|
||
|
|
)
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def many_to_many(self):
|
||
|
|
"""
|
||
|
|
Return a list of all many to many fields on the model and its parents.
|
||
|
|
|
||
|
|
Private API intended only to be used by Django itself; get_fields()
|
||
|
|
combined with filtering of field properties is the public API for
|
||
|
|
obtaining this list.
|
||
|
|
"""
|
||
|
|
return make_immutable_fields_list(
|
||
|
|
"many_to_many",
|
||
|
|
(
|
||
|
|
f
|
||
|
|
for f in self._get_fields(reverse=False)
|
||
|
|
if f.is_relation and f.many_to_many
|
||
|
|
),
|
||
|
|
)
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def related_objects(self):
|
||
|
|
"""
|
||
|
|
Return all related objects pointing to the current model. The related
|
||
|
|
objects can come from a one-to-one, one-to-many, or many-to-many field
|
||
|
|
relation type.
|
||
|
|
|
||
|
|
Private API intended only to be used by Django itself; get_fields()
|
||
|
|
combined with filtering of field properties is the public API for
|
||
|
|
obtaining this field list.
|
||
|
|
"""
|
||
|
|
all_related_fields = self._get_fields(
|
||
|
|
forward=False, reverse=True, include_hidden=True
|
||
|
|
)
|
||
|
|
return make_immutable_fields_list(
|
||
|
|
"related_objects",
|
||
|
|
(
|
||
|
|
obj
|
||
|
|
for obj in all_related_fields
|
||
|
|
if not obj.hidden or obj.field.many_to_many
|
||
|
|
),
|
||
|
|
)
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def _forward_fields_map(self):
|
||
|
|
res = {}
|
||
|
|
fields = self._get_fields(reverse=False)
|
||
|
|
for field in fields:
|
||
|
|
res[field.name] = field
|
||
|
|
# Due to the way Django's internals work, get_field() should also
|
||
|
|
# be able to fetch a field by attname. In the case of a concrete
|
||
|
|
# field with relation, includes the *_id name too
|
||
|
|
try:
|
||
|
|
res[field.attname] = field
|
||
|
|
except AttributeError:
|
||
|
|
pass
|
||
|
|
return res
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def fields_map(self):
|
||
|
|
res = {}
|
||
|
|
fields = self._get_fields(forward=False, include_hidden=True)
|
||
|
|
for field in fields:
|
||
|
|
res[field.name] = field
|
||
|
|
# Due to the way Django's internals work, get_field() should also
|
||
|
|
# be able to fetch a field by attname. In the case of a concrete
|
||
|
|
# field with relation, includes the *_id name too
|
||
|
|
try:
|
||
|
|
res[field.attname] = field
|
||
|
|
except AttributeError:
|
||
|
|
pass
|
||
|
|
return res
|
||
|
|
|
||
|
|
def get_field(self, field_name):
|
||
|
|
"""
|
||
|
|
Return a field instance given the name of a forward or reverse field.
|
||
|
|
"""
|
||
|
|
try:
|
||
|
|
# In order to avoid premature loading of the relation tree
|
||
|
|
# (expensive) we prefer checking if the field is a forward field.
|
||
|
|
return self._forward_fields_map[field_name]
|
||
|
|
except KeyError:
|
||
|
|
# If the app registry is not ready, reverse fields are
|
||
|
|
# unavailable, therefore we throw a FieldDoesNotExist exception.
|
||
|
|
if not self.apps.models_ready:
|
||
|
|
raise FieldDoesNotExist(
|
||
|
|
"%s has no field named '%s'. The app cache isn't ready yet, "
|
||
|
|
"so if this is an auto-created related field, it won't "
|
||
|
|
"be available yet." % (self.object_name, field_name)
|
||
|
|
)
|
||
|
|
|
||
|
|
try:
|
||
|
|
# Retrieve field instance by name from cached or just-computed
|
||
|
|
# field map.
|
||
|
|
return self.fields_map[field_name]
|
||
|
|
except KeyError:
|
||
|
|
raise FieldDoesNotExist(
|
||
|
|
"%s has no field named '%s'" % (self.object_name, field_name)
|
||
|
|
)
|
||
|
|
|
||
|
|
def get_base_chain(self, model):
|
||
|
|
"""
|
||
|
|
Return a list of parent classes leading to `model` (ordered from
|
||
|
|
closest to most distant ancestor). This has to handle the case where
|
||
|
|
`model` is a grandparent or even more distant relation.
|
||
|
|
"""
|
||
|
|
if not self.parents:
|
||
|
|
return []
|
||
|
|
if model in self.parents:
|
||
|
|
return [model]
|
||
|
|
for parent in self.parents:
|
||
|
|
res = parent._meta.get_base_chain(model)
|
||
|
|
if res:
|
||
|
|
res.insert(0, parent)
|
||
|
|
return res
|
||
|
|
return []
|
||
|
|
|
||
|
|
def get_parent_list(self):
|
||
|
|
"""
|
||
|
|
Return all the ancestors of this model as a list ordered by MRO.
|
||
|
|
Useful for determining if something is an ancestor, regardless of lineage.
|
||
|
|
"""
|
||
|
|
result = OrderedSet(self.parents)
|
||
|
|
for parent in self.parents:
|
||
|
|
for ancestor in parent._meta.get_parent_list():
|
||
|
|
result.add(ancestor)
|
||
|
|
return list(result)
|
||
|
|
|
||
|
|
def get_ancestor_link(self, ancestor):
|
||
|
|
"""
|
||
|
|
Return the field on the current model which points to the given
|
||
|
|
"ancestor". This is possible an indirect link (a pointer to a parent
|
||
|
|
model, which points, eventually, to the ancestor). Used when
|
||
|
|
constructing table joins for model inheritance.
|
||
|
|
|
||
|
|
Return None if the model isn't an ancestor of this one.
|
||
|
|
"""
|
||
|
|
if ancestor in self.parents:
|
||
|
|
return self.parents[ancestor]
|
||
|
|
for parent in self.parents:
|
||
|
|
# Tries to get a link field from the immediate parent
|
||
|
|
parent_link = parent._meta.get_ancestor_link(ancestor)
|
||
|
|
if parent_link:
|
||
|
|
# In case of a proxied model, the first link
|
||
|
|
# of the chain to the ancestor is that parent
|
||
|
|
# links
|
||
|
|
return self.parents[parent] or parent_link
|
||
|
|
|
||
|
|
def get_path_to_parent(self, parent):
|
||
|
|
"""
|
||
|
|
Return a list of PathInfos containing the path from the current
|
||
|
|
model to the parent model, or an empty list if parent is not a
|
||
|
|
parent of the current model.
|
||
|
|
"""
|
||
|
|
if self.model is parent:
|
||
|
|
return []
|
||
|
|
# Skip the chain of proxy to the concrete proxied model.
|
||
|
|
proxied_model = self.concrete_model
|
||
|
|
path = []
|
||
|
|
opts = self
|
||
|
|
for int_model in self.get_base_chain(parent):
|
||
|
|
if int_model is proxied_model:
|
||
|
|
opts = int_model._meta
|
||
|
|
else:
|
||
|
|
final_field = opts.parents[int_model]
|
||
|
|
targets = (final_field.remote_field.get_related_field(),)
|
||
|
|
opts = int_model._meta
|
||
|
|
path.append(
|
||
|
|
PathInfo(
|
||
|
|
from_opts=final_field.model._meta,
|
||
|
|
to_opts=opts,
|
||
|
|
target_fields=targets,
|
||
|
|
join_field=final_field,
|
||
|
|
m2m=False,
|
||
|
|
direct=True,
|
||
|
|
filtered_relation=None,
|
||
|
|
)
|
||
|
|
)
|
||
|
|
return path
|
||
|
|
|
||
|
|
def get_path_from_parent(self, parent):
|
||
|
|
"""
|
||
|
|
Return a list of PathInfos containing the path from the parent
|
||
|
|
model to the current model, or an empty list if parent is not a
|
||
|
|
parent of the current model.
|
||
|
|
"""
|
||
|
|
if self.model is parent:
|
||
|
|
return []
|
||
|
|
model = self.concrete_model
|
||
|
|
# Get a reversed base chain including both the current and parent
|
||
|
|
# models.
|
||
|
|
chain = model._meta.get_base_chain(parent)
|
||
|
|
chain.reverse()
|
||
|
|
chain.append(model)
|
||
|
|
# Construct a list of the PathInfos between models in chain.
|
||
|
|
path = []
|
||
|
|
for i, ancestor in enumerate(chain[:-1]):
|
||
|
|
child = chain[i + 1]
|
||
|
|
link = child._meta.get_ancestor_link(ancestor)
|
||
|
|
path.extend(link.reverse_path_infos)
|
||
|
|
return path
|
||
|
|
|
||
|
|
def _populate_directed_relation_graph(self):
|
||
|
|
"""
|
||
|
|
This method is used by each model to find its reverse objects. As this
|
||
|
|
method is very expensive and is accessed frequently (it looks up every
|
||
|
|
field in a model, in every app), it is computed on first access and then
|
||
|
|
is set as a property on every model.
|
||
|
|
"""
|
||
|
|
related_objects_graph = defaultdict(list)
|
||
|
|
|
||
|
|
all_models = self.apps.get_models(include_auto_created=True)
|
||
|
|
for model in all_models:
|
||
|
|
opts = model._meta
|
||
|
|
# Abstract model's fields are copied to child models, hence we will
|
||
|
|
# see the fields from the child models.
|
||
|
|
if opts.abstract:
|
||
|
|
continue
|
||
|
|
fields_with_relations = (
|
||
|
|
f
|
||
|
|
for f in opts._get_fields(reverse=False, include_parents=False)
|
||
|
|
if f.is_relation and f.related_model is not None
|
||
|
|
)
|
||
|
|
for f in fields_with_relations:
|
||
|
|
if not isinstance(f.remote_field.model, str):
|
||
|
|
remote_label = f.remote_field.model._meta.concrete_model._meta.label
|
||
|
|
related_objects_graph[remote_label].append(f)
|
||
|
|
|
||
|
|
for model in all_models:
|
||
|
|
# Set the relation_tree using the internal __dict__. In this way
|
||
|
|
# we avoid calling the cached property. In attribute lookup,
|
||
|
|
# __dict__ takes precedence over a data descriptor (such as
|
||
|
|
# @cached_property). This means that the _meta._relation_tree is
|
||
|
|
# only called if related_objects is not in __dict__.
|
||
|
|
related_objects = related_objects_graph[
|
||
|
|
model._meta.concrete_model._meta.label
|
||
|
|
]
|
||
|
|
model._meta.__dict__["_relation_tree"] = related_objects
|
||
|
|
# It seems it is possible that self is not in all_models, so guard
|
||
|
|
# against that with default for get().
|
||
|
|
return self.__dict__.get("_relation_tree", EMPTY_RELATION_TREE)
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def _relation_tree(self):
|
||
|
|
return self._populate_directed_relation_graph()
|
||
|
|
|
||
|
|
def _expire_cache(self, forward=True, reverse=True):
|
||
|
|
# This method is usually called by apps.cache_clear(), when the
|
||
|
|
# registry is finalized, or when a new field is added.
|
||
|
|
if forward:
|
||
|
|
for cache_key in self.FORWARD_PROPERTIES:
|
||
|
|
if cache_key in self.__dict__:
|
||
|
|
delattr(self, cache_key)
|
||
|
|
if reverse and not self.abstract:
|
||
|
|
for cache_key in self.REVERSE_PROPERTIES:
|
||
|
|
if cache_key in self.__dict__:
|
||
|
|
delattr(self, cache_key)
|
||
|
|
self._get_fields_cache = {}
|
||
|
|
|
||
|
|
def get_fields(self, include_parents=True, include_hidden=False):
|
||
|
|
"""
|
||
|
|
Return a list of fields associated to the model. By default, include
|
||
|
|
forward and reverse fields, fields derived from inheritance, but not
|
||
|
|
hidden fields. The returned fields can be changed using the parameters:
|
||
|
|
|
||
|
|
- include_parents: include fields derived from inheritance
|
||
|
|
- include_hidden: include fields that have a related_name that
|
||
|
|
starts with a "+"
|
||
|
|
"""
|
||
|
|
if include_parents is False:
|
||
|
|
include_parents = PROXY_PARENTS
|
||
|
|
return self._get_fields(
|
||
|
|
include_parents=include_parents, include_hidden=include_hidden
|
||
|
|
)
|
||
|
|
|
||
|
|
def _get_fields(
|
||
|
|
self,
|
||
|
|
forward=True,
|
||
|
|
reverse=True,
|
||
|
|
include_parents=True,
|
||
|
|
include_hidden=False,
|
||
|
|
seen_models=None,
|
||
|
|
):
|
||
|
|
"""
|
||
|
|
Internal helper function to return fields of the model.
|
||
|
|
* If forward=True, then fields defined on this model are returned.
|
||
|
|
* If reverse=True, then relations pointing to this model are returned.
|
||
|
|
* If include_hidden=True, then fields with is_hidden=True are returned.
|
||
|
|
* The include_parents argument toggles if fields from parent models
|
||
|
|
should be included. It has three values: True, False, and
|
||
|
|
PROXY_PARENTS. When set to PROXY_PARENTS, the call will return all
|
||
|
|
fields defined for the current model or any of its parents in the
|
||
|
|
parent chain to the model's concrete model.
|
||
|
|
"""
|
||
|
|
if include_parents not in (True, False, PROXY_PARENTS):
|
||
|
|
raise TypeError(
|
||
|
|
"Invalid argument for include_parents: %s" % (include_parents,)
|
||
|
|
)
|
||
|
|
# This helper function is used to allow recursion in ``get_fields()``
|
||
|
|
# implementation and to provide a fast way for Django's internals to
|
||
|
|
# access specific subsets of fields.
|
||
|
|
|
||
|
|
# We must keep track of which models we have already seen. Otherwise we
|
||
|
|
# could include the same field multiple times from different models.
|
||
|
|
topmost_call = seen_models is None
|
||
|
|
if topmost_call:
|
||
|
|
seen_models = set()
|
||
|
|
seen_models.add(self.model)
|
||
|
|
|
||
|
|
# Creates a cache key composed of all arguments
|
||
|
|
cache_key = (forward, reverse, include_parents, include_hidden, topmost_call)
|
||
|
|
|
||
|
|
try:
|
||
|
|
# In order to avoid list manipulation. Always return a shallow copy
|
||
|
|
# of the results.
|
||
|
|
return self._get_fields_cache[cache_key]
|
||
|
|
except KeyError:
|
||
|
|
pass
|
||
|
|
|
||
|
|
fields = []
|
||
|
|
# Recursively call _get_fields() on each parent, with the same
|
||
|
|
# options provided in this call.
|
||
|
|
if include_parents is not False:
|
||
|
|
for parent in self.parents:
|
||
|
|
# In diamond inheritance it is possible that we see the same
|
||
|
|
# model from two different routes. In that case, avoid adding
|
||
|
|
# fields from the same parent again.
|
||
|
|
if parent in seen_models:
|
||
|
|
continue
|
||
|
|
if (
|
||
|
|
parent._meta.concrete_model != self.concrete_model
|
||
|
|
and include_parents == PROXY_PARENTS
|
||
|
|
):
|
||
|
|
continue
|
||
|
|
for obj in parent._meta._get_fields(
|
||
|
|
forward=forward,
|
||
|
|
reverse=reverse,
|
||
|
|
include_parents=include_parents,
|
||
|
|
include_hidden=include_hidden,
|
||
|
|
seen_models=seen_models,
|
||
|
|
):
|
||
|
|
if (
|
||
|
|
not getattr(obj, "parent_link", False)
|
||
|
|
or obj.model == self.concrete_model
|
||
|
|
):
|
||
|
|
fields.append(obj)
|
||
|
|
if reverse and not self.proxy:
|
||
|
|
# Tree is computed once and cached until the app cache is expired.
|
||
|
|
# It is composed of a list of fields pointing to the current model
|
||
|
|
# from other models.
|
||
|
|
all_fields = self._relation_tree
|
||
|
|
for field in all_fields:
|
||
|
|
# If hidden fields should be included or the relation is not
|
||
|
|
# intentionally hidden, add to the fields dict.
|
||
|
|
if include_hidden or not field.remote_field.hidden:
|
||
|
|
fields.append(field.remote_field)
|
||
|
|
|
||
|
|
if forward:
|
||
|
|
fields += self.local_fields
|
||
|
|
fields += self.local_many_to_many
|
||
|
|
# Private fields are recopied to each child model, and they get a
|
||
|
|
# different model as field.model in each child. Hence we have to
|
||
|
|
# add the private fields separately from the topmost call. If we
|
||
|
|
# did this recursively similar to local_fields, we would get field
|
||
|
|
# instances with field.model != self.model.
|
||
|
|
if topmost_call:
|
||
|
|
fields += self.private_fields
|
||
|
|
|
||
|
|
# In order to avoid list manipulation. Always
|
||
|
|
# return a shallow copy of the results
|
||
|
|
fields = make_immutable_fields_list("get_fields()", fields)
|
||
|
|
|
||
|
|
# Store result into cache for later access
|
||
|
|
self._get_fields_cache[cache_key] = fields
|
||
|
|
return fields
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def total_unique_constraints(self):
|
||
|
|
"""
|
||
|
|
Return a list of total unique constraints. Useful for determining set
|
||
|
|
of fields guaranteed to be unique for all rows.
|
||
|
|
"""
|
||
|
|
return [
|
||
|
|
constraint
|
||
|
|
for constraint in self.constraints
|
||
|
|
if (
|
||
|
|
isinstance(constraint, UniqueConstraint)
|
||
|
|
and constraint.condition is None
|
||
|
|
and not constraint.contains_expressions
|
||
|
|
)
|
||
|
|
]
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def _property_names(self):
|
||
|
|
"""Return a set of the names of the properties defined on the model."""
|
||
|
|
names = []
|
||
|
|
for name in dir(self.model):
|
||
|
|
attr = inspect.getattr_static(self.model, name)
|
||
|
|
if isinstance(attr, property):
|
||
|
|
names.append(name)
|
||
|
|
return frozenset(names)
|
||
|
|
|
||
|
|
@cached_property
|
||
|
|
def db_returning_fields(self):
|
||
|
|
"""
|
||
|
|
Private API intended only to be used by Django itself.
|
||
|
|
Fields to be returned after a database insert.
|
||
|
|
"""
|
||
|
|
return [
|
||
|
|
field
|
||
|
|
for field in self._get_fields(
|
||
|
|
forward=True, reverse=False, include_parents=PROXY_PARENTS
|
||
|
|
)
|
||
|
|
if getattr(field, "db_returning", False)
|
||
|
|
]
|