986 lines
40 KiB
Python
986 lines
40 KiB
Python
import copy
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from collections import defaultdict
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from contextlib import contextmanager
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from functools import partial
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from django.apps import AppConfig
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from django.apps.registry import Apps
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from django.apps.registry import apps as global_apps
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from django.conf import settings
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from django.core.exceptions import FieldDoesNotExist
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from django.db import models
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from django.db.migrations.utils import field_is_referenced, get_references
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from django.db.models import NOT_PROVIDED
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from django.db.models.fields.related import RECURSIVE_RELATIONSHIP_CONSTANT
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from django.db.models.options import DEFAULT_NAMES, normalize_together
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from django.db.models.utils import make_model_tuple
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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.version import get_docs_version
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from .exceptions import InvalidBasesError
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from .utils import resolve_relation
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def _get_app_label_and_model_name(model, app_label=""):
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if isinstance(model, str):
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split = model.split(".", 1)
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return tuple(split) if len(split) == 2 else (app_label, split[0])
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else:
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return model._meta.app_label, model._meta.model_name
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def _get_related_models(m):
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"""Return all models that have a direct relationship to the given model."""
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related_models = [
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subclass
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for subclass in m.__subclasses__()
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if issubclass(subclass, models.Model)
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]
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related_fields_models = set()
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for f in m._meta.get_fields(include_parents=True, include_hidden=True):
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if (
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f.is_relation
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and f.related_model is not None
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and not isinstance(f.related_model, str)
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):
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related_fields_models.add(f.model)
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related_models.append(f.related_model)
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# Reverse accessors of foreign keys to proxy models are attached to their
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# concrete proxied model.
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opts = m._meta
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if opts.proxy and m in related_fields_models:
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related_models.append(opts.concrete_model)
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return related_models
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def get_related_models_tuples(model):
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"""
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Return a list of typical (app_label, model_name) tuples for all related
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models for the given model.
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"""
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return {
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(rel_mod._meta.app_label, rel_mod._meta.model_name)
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for rel_mod in _get_related_models(model)
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}
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def get_related_models_recursive(model):
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"""
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Return all models that have a direct or indirect relationship
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to the given model.
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Relationships are either defined by explicit relational fields, like
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ForeignKey, ManyToManyField or OneToOneField, or by inheriting from another
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model (a superclass is related to its subclasses, but not vice versa). Note,
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however, that a model inheriting from a concrete model is also related to
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its superclass through the implicit *_ptr OneToOneField on the subclass.
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"""
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seen = set()
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queue = _get_related_models(model)
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for rel_mod in queue:
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rel_app_label, rel_model_name = (
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rel_mod._meta.app_label,
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rel_mod._meta.model_name,
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)
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if (rel_app_label, rel_model_name) in seen:
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continue
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seen.add((rel_app_label, rel_model_name))
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queue.extend(_get_related_models(rel_mod))
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return seen - {(model._meta.app_label, model._meta.model_name)}
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class ProjectState:
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"""
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Represent the entire project's overall state. This is the item that is
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passed around - do it here rather than at the app level so that cross-app
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FKs/etc. resolve properly.
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"""
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def __init__(self, models=None, real_apps=None):
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self.models = models or {}
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# Apps to include from main registry, usually unmigrated ones
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if real_apps is None:
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real_apps = set()
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else:
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assert isinstance(real_apps, set)
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self.real_apps = real_apps
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self.is_delayed = False
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# {remote_model_key: {model_key: {field_name: field}}}
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self._relations = None
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@property
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def relations(self):
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if self._relations is None:
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self.resolve_fields_and_relations()
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return self._relations
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def add_model(self, model_state):
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model_key = model_state.app_label, model_state.name_lower
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self.models[model_key] = model_state
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if self._relations is not None:
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self.resolve_model_relations(model_key)
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if "apps" in self.__dict__: # hasattr would cache the property
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self.reload_model(*model_key)
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def remove_model(self, app_label, model_name):
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model_key = app_label, model_name
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del self.models[model_key]
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if self._relations is not None:
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self._relations.pop(model_key, None)
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# Call list() since _relations can change size during iteration.
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for related_model_key, model_relations in list(self._relations.items()):
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model_relations.pop(model_key, None)
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if not model_relations:
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del self._relations[related_model_key]
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if "apps" in self.__dict__: # hasattr would cache the property
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self.apps.unregister_model(*model_key)
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# Need to do this explicitly since unregister_model() doesn't clear
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# the cache automatically (#24513)
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self.apps.clear_cache()
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def rename_model(self, app_label, old_name, new_name):
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# Add a new model.
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old_name_lower = old_name.lower()
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new_name_lower = new_name.lower()
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renamed_model = self.models[app_label, old_name_lower].clone()
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renamed_model.name = new_name
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self.models[app_label, new_name_lower] = renamed_model
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# Repoint all fields pointing to the old model to the new one.
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old_model_tuple = (app_label, old_name_lower)
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new_remote_model = f"{app_label}.{new_name}"
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to_reload = set()
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for model_state, name, field, reference in get_references(
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self, old_model_tuple
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):
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changed_field = None
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if reference.to:
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changed_field = field.clone()
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changed_field.remote_field.model = new_remote_model
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if reference.through:
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if changed_field is None:
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changed_field = field.clone()
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changed_field.remote_field.through = new_remote_model
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if changed_field:
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model_state.fields[name] = changed_field
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to_reload.add((model_state.app_label, model_state.name_lower))
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if self._relations is not None:
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old_name_key = app_label, old_name_lower
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new_name_key = app_label, new_name_lower
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if old_name_key in self._relations:
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self._relations[new_name_key] = self._relations.pop(old_name_key)
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for model_relations in self._relations.values():
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if old_name_key in model_relations:
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model_relations[new_name_key] = model_relations.pop(old_name_key)
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# Reload models related to old model before removing the old model.
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self.reload_models(to_reload, delay=True)
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# Remove the old model.
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self.remove_model(app_label, old_name_lower)
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self.reload_model(app_label, new_name_lower, delay=True)
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def alter_model_options(self, app_label, model_name, options, option_keys=None):
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model_state = self.models[app_label, model_name]
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model_state.options = {**model_state.options, **options}
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if option_keys:
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for key in option_keys:
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if key not in options:
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model_state.options.pop(key, False)
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self.reload_model(app_label, model_name, delay=True)
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def remove_model_options(self, app_label, model_name, option_name, value_to_remove):
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model_state = self.models[app_label, model_name]
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if objs := model_state.options.get(option_name):
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model_state.options[option_name] = [
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obj for obj in objs if tuple(obj) != tuple(value_to_remove)
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]
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self.reload_model(app_label, model_name, delay=True)
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def alter_model_managers(self, app_label, model_name, managers):
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model_state = self.models[app_label, model_name]
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model_state.managers = list(managers)
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self.reload_model(app_label, model_name, delay=True)
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def _append_option(self, app_label, model_name, option_name, obj):
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model_state = self.models[app_label, model_name]
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model_state.options[option_name] = [*model_state.options[option_name], obj]
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self.reload_model(app_label, model_name, delay=True)
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def _remove_option(self, app_label, model_name, option_name, obj_name):
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model_state = self.models[app_label, model_name]
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objs = model_state.options[option_name]
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model_state.options[option_name] = [obj for obj in objs if obj.name != obj_name]
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self.reload_model(app_label, model_name, delay=True)
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def add_index(self, app_label, model_name, index):
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self._append_option(app_label, model_name, "indexes", index)
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def remove_index(self, app_label, model_name, index_name):
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self._remove_option(app_label, model_name, "indexes", index_name)
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def rename_index(self, app_label, model_name, old_index_name, new_index_name):
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model_state = self.models[app_label, model_name]
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objs = model_state.options["indexes"]
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new_indexes = []
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for obj in objs:
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if obj.name == old_index_name:
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obj = obj.clone()
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obj.name = new_index_name
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new_indexes.append(obj)
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model_state.options["indexes"] = new_indexes
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self.reload_model(app_label, model_name, delay=True)
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def add_constraint(self, app_label, model_name, constraint):
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self._append_option(app_label, model_name, "constraints", constraint)
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def remove_constraint(self, app_label, model_name, constraint_name):
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self._remove_option(app_label, model_name, "constraints", constraint_name)
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def add_field(self, app_label, model_name, name, field, preserve_default):
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# If preserve default is off, don't use the default for future state.
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if not preserve_default:
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field = field.clone()
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field.default = NOT_PROVIDED
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else:
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field = field
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model_key = app_label, model_name
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self.models[model_key].fields[name] = field
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if self._relations is not None:
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self.resolve_model_field_relations(model_key, name, field)
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# Delay rendering of relationships if it's not a relational field.
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delay = not field.is_relation
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self.reload_model(*model_key, delay=delay)
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def remove_field(self, app_label, model_name, name):
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model_key = app_label, model_name
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model_state = self.models[model_key]
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old_field = model_state.fields.pop(name)
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if self._relations is not None:
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self.resolve_model_field_relations(model_key, name, old_field)
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# Delay rendering of relationships if it's not a relational field.
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delay = not old_field.is_relation
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self.reload_model(*model_key, delay=delay)
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def alter_field(self, app_label, model_name, name, field, preserve_default):
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if not preserve_default:
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field = field.clone()
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field.default = NOT_PROVIDED
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else:
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field = field
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model_key = app_label, model_name
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fields = self.models[model_key].fields
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if self._relations is not None:
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old_field = fields.pop(name)
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if old_field.is_relation:
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self.resolve_model_field_relations(model_key, name, old_field)
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fields[name] = field
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if field.is_relation:
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self.resolve_model_field_relations(model_key, name, field)
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else:
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fields[name] = field
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# TODO: investigate if old relational fields must be reloaded or if
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# it's sufficient if the new field is (#27737).
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# Delay rendering of relationships if it's not a relational field and
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# not referenced by a foreign key.
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delay = not field.is_relation and not field_is_referenced(
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self, model_key, (name, field)
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)
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self.reload_model(*model_key, delay=delay)
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def rename_field(self, app_label, model_name, old_name, new_name):
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model_key = app_label, model_name
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model_state = self.models[model_key]
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# Rename the field.
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fields = model_state.fields
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try:
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found = fields.pop(old_name)
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except KeyError:
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raise FieldDoesNotExist(
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f"{app_label}.{model_name} has no field named '{old_name}'"
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)
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fields[new_name] = found
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for field in fields.values():
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# Fix from_fields to refer to the new field.
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from_fields = getattr(field, "from_fields", None)
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if from_fields:
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field.from_fields = tuple(
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[
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new_name if from_field_name == old_name else from_field_name
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for from_field_name in from_fields
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]
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)
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# Fix index/unique_together to refer to the new field.
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options = model_state.options
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for option in ("index_together", "unique_together"):
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if option in options:
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options[option] = [
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[new_name if n == old_name else n for n in together]
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for together in options[option]
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]
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# Fix to_fields to refer to the new field.
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delay = True
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references = get_references(self, model_key, (old_name, found))
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for *_, field, reference in references:
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delay = False
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if reference.to:
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remote_field, to_fields = reference.to
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if getattr(remote_field, "field_name", None) == old_name:
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remote_field.field_name = new_name
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if to_fields:
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field.to_fields = tuple(
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[
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new_name if to_field_name == old_name else to_field_name
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for to_field_name in to_fields
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]
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)
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if self._relations is not None:
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old_name_lower = old_name.lower()
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new_name_lower = new_name.lower()
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for to_model in self._relations.values():
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if old_name_lower in to_model[model_key]:
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field = to_model[model_key].pop(old_name_lower)
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field.name = new_name_lower
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to_model[model_key][new_name_lower] = field
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self.reload_model(*model_key, delay=delay)
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def _find_reload_model(self, app_label, model_name, delay=False):
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if delay:
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self.is_delayed = True
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related_models = set()
|
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try:
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old_model = self.apps.get_model(app_label, model_name)
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except LookupError:
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pass
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else:
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# Get all relations to and from the old model before reloading,
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# as _meta.apps may change
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if delay:
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related_models = get_related_models_tuples(old_model)
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else:
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related_models = get_related_models_recursive(old_model)
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# Get all outgoing references from the model to be rendered
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model_state = self.models[(app_label, model_name)]
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# Directly related models are the models pointed to by ForeignKeys,
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# OneToOneFields, and ManyToManyFields.
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direct_related_models = set()
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for field in model_state.fields.values():
|
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if field.is_relation:
|
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if field.remote_field.model == RECURSIVE_RELATIONSHIP_CONSTANT:
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continue
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rel_app_label, rel_model_name = _get_app_label_and_model_name(
|
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field.related_model, app_label
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)
|
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direct_related_models.add((rel_app_label, rel_model_name.lower()))
|
|
|
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# For all direct related models recursively get all related models.
|
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related_models.update(direct_related_models)
|
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for rel_app_label, rel_model_name in direct_related_models:
|
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try:
|
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rel_model = self.apps.get_model(rel_app_label, rel_model_name)
|
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except LookupError:
|
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pass
|
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else:
|
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if delay:
|
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related_models.update(get_related_models_tuples(rel_model))
|
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else:
|
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related_models.update(get_related_models_recursive(rel_model))
|
|
|
|
# Include the model itself
|
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related_models.add((app_label, model_name))
|
|
|
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return related_models
|
|
|
|
def reload_model(self, app_label, model_name, delay=False):
|
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if "apps" in self.__dict__: # hasattr would cache the property
|
|
related_models = self._find_reload_model(app_label, model_name, delay)
|
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self._reload(related_models)
|
|
|
|
def reload_models(self, models, delay=True):
|
|
if "apps" in self.__dict__: # hasattr would cache the property
|
|
related_models = set()
|
|
for app_label, model_name in models:
|
|
related_models.update(
|
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self._find_reload_model(app_label, model_name, delay)
|
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)
|
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self._reload(related_models)
|
|
|
|
def _reload(self, related_models):
|
|
# Unregister all related models
|
|
with self.apps.bulk_update():
|
|
for rel_app_label, rel_model_name in related_models:
|
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self.apps.unregister_model(rel_app_label, rel_model_name)
|
|
|
|
states_to_be_rendered = []
|
|
# Gather all models states of those models that will be rerendered.
|
|
# This includes:
|
|
# 1. All related models of unmigrated apps
|
|
for model_state in self.apps.real_models:
|
|
if (model_state.app_label, model_state.name_lower) in related_models:
|
|
states_to_be_rendered.append(model_state)
|
|
|
|
# 2. All related models of migrated apps
|
|
for rel_app_label, rel_model_name in related_models:
|
|
try:
|
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model_state = self.models[rel_app_label, rel_model_name]
|
|
except KeyError:
|
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pass
|
|
else:
|
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states_to_be_rendered.append(model_state)
|
|
|
|
# Render all models
|
|
self.apps.render_multiple(states_to_be_rendered)
|
|
|
|
def update_model_field_relation(
|
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self,
|
|
model,
|
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model_key,
|
|
field_name,
|
|
field,
|
|
concretes,
|
|
):
|
|
remote_model_key = resolve_relation(model, *model_key)
|
|
if remote_model_key[0] not in self.real_apps and remote_model_key in concretes:
|
|
remote_model_key = concretes[remote_model_key]
|
|
relations_to_remote_model = self._relations[remote_model_key]
|
|
if field_name in self.models[model_key].fields:
|
|
# The assert holds because it's a new relation, or an altered
|
|
# relation, in which case references have been removed by
|
|
# alter_field().
|
|
assert field_name not in relations_to_remote_model[model_key]
|
|
relations_to_remote_model[model_key][field_name] = field
|
|
else:
|
|
del relations_to_remote_model[model_key][field_name]
|
|
if not relations_to_remote_model[model_key]:
|
|
del relations_to_remote_model[model_key]
|
|
|
|
def resolve_model_field_relations(
|
|
self,
|
|
model_key,
|
|
field_name,
|
|
field,
|
|
concretes=None,
|
|
):
|
|
remote_field = field.remote_field
|
|
if not remote_field:
|
|
return
|
|
if concretes is None:
|
|
concretes, _ = self._get_concrete_models_mapping_and_proxy_models()
|
|
|
|
self.update_model_field_relation(
|
|
remote_field.model,
|
|
model_key,
|
|
field_name,
|
|
field,
|
|
concretes,
|
|
)
|
|
|
|
through = getattr(remote_field, "through", None)
|
|
if not through:
|
|
return
|
|
self.update_model_field_relation(
|
|
through, model_key, field_name, field, concretes
|
|
)
|
|
|
|
def resolve_model_relations(self, model_key, concretes=None):
|
|
if concretes is None:
|
|
concretes, _ = self._get_concrete_models_mapping_and_proxy_models()
|
|
|
|
model_state = self.models[model_key]
|
|
for field_name, field in model_state.fields.items():
|
|
self.resolve_model_field_relations(model_key, field_name, field, concretes)
|
|
|
|
def resolve_fields_and_relations(self):
|
|
# Resolve fields.
|
|
for model_state in self.models.values():
|
|
for field_name, field in model_state.fields.items():
|
|
field.name = field_name
|
|
# Resolve relations.
|
|
# {remote_model_key: {model_key: {field_name: field}}}
|
|
self._relations = defaultdict(partial(defaultdict, dict))
|
|
concretes, proxies = self._get_concrete_models_mapping_and_proxy_models()
|
|
|
|
for model_key in concretes:
|
|
self.resolve_model_relations(model_key, concretes)
|
|
|
|
for model_key in proxies:
|
|
self._relations[model_key] = self._relations[concretes[model_key]]
|
|
|
|
def get_concrete_model_key(self, model):
|
|
(
|
|
concrete_models_mapping,
|
|
_,
|
|
) = self._get_concrete_models_mapping_and_proxy_models()
|
|
model_key = make_model_tuple(model)
|
|
return concrete_models_mapping[model_key]
|
|
|
|
def _get_concrete_models_mapping_and_proxy_models(self):
|
|
concrete_models_mapping = {}
|
|
proxy_models = {}
|
|
# Split models to proxy and concrete models.
|
|
for model_key, model_state in self.models.items():
|
|
if model_state.options.get("proxy"):
|
|
proxy_models[model_key] = model_state
|
|
# Find a concrete model for the proxy.
|
|
concrete_models_mapping[
|
|
model_key
|
|
] = self._find_concrete_model_from_proxy(
|
|
proxy_models,
|
|
model_state,
|
|
)
|
|
else:
|
|
concrete_models_mapping[model_key] = model_key
|
|
return concrete_models_mapping, proxy_models
|
|
|
|
def _find_concrete_model_from_proxy(self, proxy_models, model_state):
|
|
for base in model_state.bases:
|
|
if not (isinstance(base, str) or issubclass(base, models.Model)):
|
|
continue
|
|
base_key = make_model_tuple(base)
|
|
base_state = proxy_models.get(base_key)
|
|
if not base_state:
|
|
# Concrete model found, stop looking at bases.
|
|
return base_key
|
|
return self._find_concrete_model_from_proxy(proxy_models, base_state)
|
|
|
|
def clone(self):
|
|
"""Return an exact copy of this ProjectState."""
|
|
new_state = ProjectState(
|
|
models={k: v.clone() for k, v in self.models.items()},
|
|
real_apps=self.real_apps,
|
|
)
|
|
if "apps" in self.__dict__:
|
|
new_state.apps = self.apps.clone()
|
|
new_state.is_delayed = self.is_delayed
|
|
return new_state
|
|
|
|
def clear_delayed_apps_cache(self):
|
|
if self.is_delayed and "apps" in self.__dict__:
|
|
del self.__dict__["apps"]
|
|
|
|
@cached_property
|
|
def apps(self):
|
|
return StateApps(self.real_apps, self.models)
|
|
|
|
@classmethod
|
|
def from_apps(cls, apps):
|
|
"""Take an Apps and return a ProjectState matching it."""
|
|
app_models = {}
|
|
for model in apps.get_models(include_swapped=True):
|
|
model_state = ModelState.from_model(model)
|
|
app_models[(model_state.app_label, model_state.name_lower)] = model_state
|
|
return cls(app_models)
|
|
|
|
def __eq__(self, other):
|
|
return self.models == other.models and self.real_apps == other.real_apps
|
|
|
|
|
|
class AppConfigStub(AppConfig):
|
|
"""Stub of an AppConfig. Only provides a label and a dict of models."""
|
|
|
|
def __init__(self, label):
|
|
self.apps = None
|
|
self.models = {}
|
|
# App-label and app-name are not the same thing, so technically passing
|
|
# in the label here is wrong. In practice, migrations don't care about
|
|
# the app name, but we need something unique, and the label works fine.
|
|
self.label = label
|
|
self.name = label
|
|
|
|
def import_models(self):
|
|
self.models = self.apps.all_models[self.label]
|
|
|
|
|
|
class StateApps(Apps):
|
|
"""
|
|
Subclass of the global Apps registry class to better handle dynamic model
|
|
additions and removals.
|
|
"""
|
|
|
|
def __init__(self, real_apps, models, ignore_swappable=False):
|
|
# Any apps in self.real_apps should have all their models included
|
|
# in the render. We don't use the original model instances as there
|
|
# are some variables that refer to the Apps object.
|
|
# FKs/M2Ms from real apps are also not included as they just
|
|
# mess things up with partial states (due to lack of dependencies)
|
|
self.real_models = []
|
|
for app_label in real_apps:
|
|
app = global_apps.get_app_config(app_label)
|
|
for model in app.get_models():
|
|
self.real_models.append(ModelState.from_model(model, exclude_rels=True))
|
|
# Populate the app registry with a stub for each application.
|
|
app_labels = {model_state.app_label for model_state in models.values()}
|
|
app_configs = [
|
|
AppConfigStub(label) for label in sorted([*real_apps, *app_labels])
|
|
]
|
|
super().__init__(app_configs)
|
|
|
|
# These locks get in the way of copying as implemented in clone(),
|
|
# which is called whenever Django duplicates a StateApps before
|
|
# updating it.
|
|
self._lock = None
|
|
self.ready_event = None
|
|
|
|
self.render_multiple([*models.values(), *self.real_models])
|
|
|
|
# There shouldn't be any operations pending at this point.
|
|
from django.core.checks.model_checks import _check_lazy_references
|
|
|
|
ignore = (
|
|
{make_model_tuple(settings.AUTH_USER_MODEL)} if ignore_swappable else set()
|
|
)
|
|
errors = _check_lazy_references(self, ignore=ignore)
|
|
if errors:
|
|
raise ValueError("\n".join(error.msg for error in errors))
|
|
|
|
@contextmanager
|
|
def bulk_update(self):
|
|
# Avoid clearing each model's cache for each change. Instead, clear
|
|
# all caches when we're finished updating the model instances.
|
|
ready = self.ready
|
|
self.ready = False
|
|
try:
|
|
yield
|
|
finally:
|
|
self.ready = ready
|
|
self.clear_cache()
|
|
|
|
def render_multiple(self, model_states):
|
|
# We keep trying to render the models in a loop, ignoring invalid
|
|
# base errors, until the size of the unrendered models doesn't
|
|
# decrease by at least one, meaning there's a base dependency loop/
|
|
# missing base.
|
|
if not model_states:
|
|
return
|
|
# Prevent that all model caches are expired for each render.
|
|
with self.bulk_update():
|
|
unrendered_models = model_states
|
|
while unrendered_models:
|
|
new_unrendered_models = []
|
|
for model in unrendered_models:
|
|
try:
|
|
model.render(self)
|
|
except InvalidBasesError:
|
|
new_unrendered_models.append(model)
|
|
if len(new_unrendered_models) == len(unrendered_models):
|
|
raise InvalidBasesError(
|
|
"Cannot resolve bases for %r\nThis can happen if you are "
|
|
"inheriting models from an app with migrations (e.g. "
|
|
"contrib.auth)\n in an app with no migrations; see "
|
|
"https://docs.djangoproject.com/en/%s/topics/migrations/"
|
|
"#dependencies for more"
|
|
% (new_unrendered_models, get_docs_version())
|
|
)
|
|
unrendered_models = new_unrendered_models
|
|
|
|
def clone(self):
|
|
"""Return a clone of this registry."""
|
|
clone = StateApps([], {})
|
|
clone.all_models = copy.deepcopy(self.all_models)
|
|
clone.app_configs = copy.deepcopy(self.app_configs)
|
|
# Set the pointer to the correct app registry.
|
|
for app_config in clone.app_configs.values():
|
|
app_config.apps = clone
|
|
# No need to actually clone them, they'll never change
|
|
clone.real_models = self.real_models
|
|
return clone
|
|
|
|
def register_model(self, app_label, model):
|
|
self.all_models[app_label][model._meta.model_name] = model
|
|
if app_label not in self.app_configs:
|
|
self.app_configs[app_label] = AppConfigStub(app_label)
|
|
self.app_configs[app_label].apps = self
|
|
self.app_configs[app_label].models[model._meta.model_name] = model
|
|
self.do_pending_operations(model)
|
|
self.clear_cache()
|
|
|
|
def unregister_model(self, app_label, model_name):
|
|
try:
|
|
del self.all_models[app_label][model_name]
|
|
del self.app_configs[app_label].models[model_name]
|
|
except KeyError:
|
|
pass
|
|
|
|
|
|
class ModelState:
|
|
"""
|
|
Represent a Django Model. Don't use the actual Model class as it's not
|
|
designed to have its options changed - instead, mutate this one and then
|
|
render it into a Model as required.
|
|
|
|
Note that while you are allowed to mutate .fields, you are not allowed
|
|
to mutate the Field instances inside there themselves - you must instead
|
|
assign new ones, as these are not detached during a clone.
|
|
"""
|
|
|
|
def __init__(
|
|
self, app_label, name, fields, options=None, bases=None, managers=None
|
|
):
|
|
self.app_label = app_label
|
|
self.name = name
|
|
self.fields = dict(fields)
|
|
self.options = options or {}
|
|
self.options.setdefault("indexes", [])
|
|
self.options.setdefault("constraints", [])
|
|
self.bases = bases or (models.Model,)
|
|
self.managers = managers or []
|
|
for name, field in self.fields.items():
|
|
# Sanity-check that fields are NOT already bound to a model.
|
|
if hasattr(field, "model"):
|
|
raise ValueError(
|
|
'ModelState.fields cannot be bound to a model - "%s" is.' % name
|
|
)
|
|
# Sanity-check that relation fields are NOT referring to a model class.
|
|
if field.is_relation and hasattr(field.related_model, "_meta"):
|
|
raise ValueError(
|
|
'ModelState.fields cannot refer to a model class - "%s.to" does. '
|
|
"Use a string reference instead." % name
|
|
)
|
|
if field.many_to_many and hasattr(field.remote_field.through, "_meta"):
|
|
raise ValueError(
|
|
'ModelState.fields cannot refer to a model class - "%s.through" '
|
|
"does. Use a string reference instead." % name
|
|
)
|
|
# Sanity-check that indexes have their name set.
|
|
for index in self.options["indexes"]:
|
|
if not index.name:
|
|
raise ValueError(
|
|
"Indexes passed to ModelState require a name attribute. "
|
|
"%r doesn't have one." % index
|
|
)
|
|
|
|
@cached_property
|
|
def name_lower(self):
|
|
return self.name.lower()
|
|
|
|
def get_field(self, field_name):
|
|
if field_name == "_order":
|
|
field_name = self.options.get("order_with_respect_to", field_name)
|
|
return self.fields[field_name]
|
|
|
|
@classmethod
|
|
def from_model(cls, model, exclude_rels=False):
|
|
"""Given a model, return a ModelState representing it."""
|
|
# Deconstruct the fields
|
|
fields = []
|
|
for field in model._meta.local_fields:
|
|
if getattr(field, "remote_field", None) and exclude_rels:
|
|
continue
|
|
if isinstance(field, models.OrderWrt):
|
|
continue
|
|
name = field.name
|
|
try:
|
|
fields.append((name, field.clone()))
|
|
except TypeError as e:
|
|
raise TypeError(
|
|
"Couldn't reconstruct field %s on %s: %s"
|
|
% (
|
|
name,
|
|
model._meta.label,
|
|
e,
|
|
)
|
|
)
|
|
if not exclude_rels:
|
|
for field in model._meta.local_many_to_many:
|
|
name = field.name
|
|
try:
|
|
fields.append((name, field.clone()))
|
|
except TypeError as e:
|
|
raise TypeError(
|
|
"Couldn't reconstruct m2m field %s on %s: %s"
|
|
% (
|
|
name,
|
|
model._meta.object_name,
|
|
e,
|
|
)
|
|
)
|
|
# Extract the options
|
|
options = {}
|
|
for name in DEFAULT_NAMES:
|
|
# Ignore some special options
|
|
if name in ["apps", "app_label"]:
|
|
continue
|
|
elif name in model._meta.original_attrs:
|
|
if name == "unique_together":
|
|
ut = model._meta.original_attrs["unique_together"]
|
|
options[name] = set(normalize_together(ut))
|
|
elif name == "index_together":
|
|
it = model._meta.original_attrs["index_together"]
|
|
options[name] = set(normalize_together(it))
|
|
elif name == "indexes":
|
|
indexes = [idx.clone() for idx in model._meta.indexes]
|
|
for index in indexes:
|
|
if not index.name:
|
|
index.set_name_with_model(model)
|
|
options["indexes"] = indexes
|
|
elif name == "constraints":
|
|
options["constraints"] = [
|
|
con.clone() for con in model._meta.constraints
|
|
]
|
|
else:
|
|
options[name] = model._meta.original_attrs[name]
|
|
# If we're ignoring relationships, remove all field-listing model
|
|
# options (that option basically just means "make a stub model")
|
|
if exclude_rels:
|
|
for key in ["unique_together", "index_together", "order_with_respect_to"]:
|
|
if key in options:
|
|
del options[key]
|
|
# Private fields are ignored, so remove options that refer to them.
|
|
elif options.get("order_with_respect_to") in {
|
|
field.name for field in model._meta.private_fields
|
|
}:
|
|
del options["order_with_respect_to"]
|
|
|
|
def flatten_bases(model):
|
|
bases = []
|
|
for base in model.__bases__:
|
|
if hasattr(base, "_meta") and base._meta.abstract:
|
|
bases.extend(flatten_bases(base))
|
|
else:
|
|
bases.append(base)
|
|
return bases
|
|
|
|
# We can't rely on __mro__ directly because we only want to flatten
|
|
# abstract models and not the whole tree. However by recursing on
|
|
# __bases__ we may end up with duplicates and ordering issues, we
|
|
# therefore discard any duplicates and reorder the bases according
|
|
# to their index in the MRO.
|
|
flattened_bases = sorted(
|
|
set(flatten_bases(model)), key=lambda x: model.__mro__.index(x)
|
|
)
|
|
|
|
# Make our record
|
|
bases = tuple(
|
|
(base._meta.label_lower if hasattr(base, "_meta") else base)
|
|
for base in flattened_bases
|
|
)
|
|
# Ensure at least one base inherits from models.Model
|
|
if not any(
|
|
(isinstance(base, str) or issubclass(base, models.Model)) for base in bases
|
|
):
|
|
bases = (models.Model,)
|
|
|
|
managers = []
|
|
manager_names = set()
|
|
default_manager_shim = None
|
|
for manager in model._meta.managers:
|
|
if manager.name in manager_names:
|
|
# Skip overridden managers.
|
|
continue
|
|
elif manager.use_in_migrations:
|
|
# Copy managers usable in migrations.
|
|
new_manager = copy.copy(manager)
|
|
new_manager._set_creation_counter()
|
|
elif manager is model._base_manager or manager is model._default_manager:
|
|
# Shim custom managers used as default and base managers.
|
|
new_manager = models.Manager()
|
|
new_manager.model = manager.model
|
|
new_manager.name = manager.name
|
|
if manager is model._default_manager:
|
|
default_manager_shim = new_manager
|
|
else:
|
|
continue
|
|
manager_names.add(manager.name)
|
|
managers.append((manager.name, new_manager))
|
|
|
|
# Ignore a shimmed default manager called objects if it's the only one.
|
|
if managers == [("objects", default_manager_shim)]:
|
|
managers = []
|
|
|
|
# Construct the new ModelState
|
|
return cls(
|
|
model._meta.app_label,
|
|
model._meta.object_name,
|
|
fields,
|
|
options,
|
|
bases,
|
|
managers,
|
|
)
|
|
|
|
def construct_managers(self):
|
|
"""Deep-clone the managers using deconstruction."""
|
|
# Sort all managers by their creation counter
|
|
sorted_managers = sorted(self.managers, key=lambda v: v[1].creation_counter)
|
|
for mgr_name, manager in sorted_managers:
|
|
as_manager, manager_path, qs_path, args, kwargs = manager.deconstruct()
|
|
if as_manager:
|
|
qs_class = import_string(qs_path)
|
|
yield mgr_name, qs_class.as_manager()
|
|
else:
|
|
manager_class = import_string(manager_path)
|
|
yield mgr_name, manager_class(*args, **kwargs)
|
|
|
|
def clone(self):
|
|
"""Return an exact copy of this ModelState."""
|
|
return self.__class__(
|
|
app_label=self.app_label,
|
|
name=self.name,
|
|
fields=dict(self.fields),
|
|
# Since options are shallow-copied here, operations such as
|
|
# AddIndex must replace their option (e.g 'indexes') rather
|
|
# than mutating it.
|
|
options=dict(self.options),
|
|
bases=self.bases,
|
|
managers=list(self.managers),
|
|
)
|
|
|
|
def render(self, apps):
|
|
"""Create a Model object from our current state into the given apps."""
|
|
# First, make a Meta object
|
|
meta_contents = {"app_label": self.app_label, "apps": apps, **self.options}
|
|
meta = type("Meta", (), meta_contents)
|
|
# Then, work out our bases
|
|
try:
|
|
bases = tuple(
|
|
(apps.get_model(base) if isinstance(base, str) else base)
|
|
for base in self.bases
|
|
)
|
|
except LookupError:
|
|
raise InvalidBasesError(
|
|
"Cannot resolve one or more bases from %r" % (self.bases,)
|
|
)
|
|
# Clone fields for the body, add other bits.
|
|
body = {name: field.clone() for name, field in self.fields.items()}
|
|
body["Meta"] = meta
|
|
body["__module__"] = "__fake__"
|
|
|
|
# Restore managers
|
|
body.update(self.construct_managers())
|
|
# Then, make a Model object (apps.register_model is called in __new__)
|
|
return type(self.name, bases, body)
|
|
|
|
def get_index_by_name(self, name):
|
|
for index in self.options["indexes"]:
|
|
if index.name == name:
|
|
return index
|
|
raise ValueError("No index named %s on model %s" % (name, self.name))
|
|
|
|
def get_constraint_by_name(self, name):
|
|
for constraint in self.options["constraints"]:
|
|
if constraint.name == name:
|
|
return constraint
|
|
raise ValueError("No constraint named %s on model %s" % (name, self.name))
|
|
|
|
def __repr__(self):
|
|
return "<%s: '%s.%s'>" % (self.__class__.__name__, self.app_label, self.name)
|
|
|
|
def __eq__(self, other):
|
|
return (
|
|
(self.app_label == other.app_label)
|
|
and (self.name == other.name)
|
|
and (len(self.fields) == len(other.fields))
|
|
and all(
|
|
k1 == k2 and f1.deconstruct()[1:] == f2.deconstruct()[1:]
|
|
for (k1, f1), (k2, f2) in zip(
|
|
sorted(self.fields.items()),
|
|
sorted(other.fields.items()),
|
|
)
|
|
)
|
|
and (self.options == other.options)
|
|
and (self.bases == other.bases)
|
|
and (self.managers == other.managers)
|
|
)
|