479 lines
20 KiB
Python
479 lines
20 KiB
Python
from __future__ import unicode_literals
|
|
from collections import OrderedDict
|
|
import copy
|
|
|
|
from django.apps import AppConfig
|
|
from django.apps.registry import Apps, apps as global_apps
|
|
from django.db import models
|
|
from django.db.models.options import DEFAULT_NAMES, normalize_together
|
|
from django.db.models.fields.related import do_pending_lookups
|
|
from django.db.models.fields.proxy import OrderWrt
|
|
from django.conf import settings
|
|
from django.utils import six
|
|
from django.utils.encoding import force_text, smart_text
|
|
from django.utils.functional import cached_property
|
|
from django.utils.module_loading import import_string
|
|
from django.utils.version import get_docs_version
|
|
|
|
|
|
class InvalidBasesError(ValueError):
|
|
pass
|
|
|
|
|
|
class ProjectState(object):
|
|
"""
|
|
Represents the entire project's overall state.
|
|
This is the item that is passed around - we do it here rather than at the
|
|
app level so that cross-app FKs/etc. resolve properly.
|
|
"""
|
|
|
|
def __init__(self, models=None, real_apps=None):
|
|
self.models = models or {}
|
|
# Apps to include from main registry, usually unmigrated ones
|
|
self.real_apps = real_apps or []
|
|
|
|
def add_model(self, model_state):
|
|
app_label, model_name = model_state.app_label, model_state.name_lower
|
|
self.models[(app_label, model_name)] = model_state
|
|
if 'apps' in self.__dict__: # hasattr would cache the property
|
|
self.reload_model(app_label, model_name)
|
|
|
|
def remove_model(self, app_label, model_name):
|
|
del self.models[app_label, model_name]
|
|
if 'apps' in self.__dict__: # hasattr would cache the property
|
|
self.apps.unregister_model(app_label, model_name)
|
|
|
|
def reload_model(self, app_label, model_name):
|
|
if 'apps' in self.__dict__: # hasattr would cache the property
|
|
# Get relations before reloading the models, as _meta.apps may change
|
|
try:
|
|
related_old = {
|
|
f.related_model for f in
|
|
self.apps.get_model(app_label, model_name)._meta.related_objects
|
|
}
|
|
except LookupError:
|
|
related_old = set()
|
|
self._reload_one_model(app_label, model_name)
|
|
# Reload models if there are relations
|
|
model = self.apps.get_model(app_label, model_name)
|
|
related_m2m = {f.related_model for f in model._meta.many_to_many}
|
|
for rel_model in related_old.union(related_m2m):
|
|
self._reload_one_model(rel_model._meta.app_label, rel_model._meta.model_name)
|
|
if related_m2m:
|
|
# Re-render this model after related models have been reloaded
|
|
self._reload_one_model(app_label, model_name)
|
|
|
|
def _reload_one_model(self, app_label, model_name):
|
|
self.apps.unregister_model(app_label, model_name)
|
|
self.models[app_label, model_name].render(self.apps)
|
|
|
|
def clone(self):
|
|
"Returns 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()
|
|
return new_state
|
|
|
|
@cached_property
|
|
def apps(self):
|
|
return StateApps(self.real_apps, self.models)
|
|
|
|
@property
|
|
def concrete_apps(self):
|
|
self.apps = StateApps(self.real_apps, self.models, ignore_swappable=True)
|
|
return self.apps
|
|
|
|
@classmethod
|
|
def from_apps(cls, apps):
|
|
"Takes in an Apps and returns 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):
|
|
if set(self.models.keys()) != set(other.models.keys()):
|
|
return False
|
|
if set(self.real_apps) != set(other.real_apps):
|
|
return False
|
|
return all(model == other.models[key] for key, model in self.models.items())
|
|
|
|
def __ne__(self, other):
|
|
return not (self == other)
|
|
|
|
|
|
class AppConfigStub(AppConfig):
|
|
"""
|
|
Stubs a Django AppConfig. Only provides a label, and a dict of models.
|
|
"""
|
|
# Not used, but required by AppConfig.__init__
|
|
path = ''
|
|
|
|
def __init__(self, label):
|
|
self.label = label
|
|
# 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.
|
|
super(AppConfigStub, self).__init__(label, None)
|
|
|
|
def import_models(self, all_models):
|
|
self.models = all_models
|
|
|
|
|
|
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)
|
|
real_models = []
|
|
for app_label in real_apps:
|
|
app = global_apps.get_app_config(app_label)
|
|
for model in app.get_models():
|
|
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 + list(app_labels))]
|
|
super(StateApps, self).__init__(app_configs)
|
|
|
|
# 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.
|
|
unrendered_models = list(models.values()) + real_models
|
|
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
|
|
|
|
# If there are some lookups left, see if we can first resolve them
|
|
# ourselves - sometimes fields are added after class_prepared is sent
|
|
for lookup_model, operations in self._pending_lookups.items():
|
|
try:
|
|
model = self.get_model(lookup_model[0], lookup_model[1])
|
|
except LookupError:
|
|
app_label = "%s.%s" % (lookup_model[0], lookup_model[1])
|
|
if app_label == settings.AUTH_USER_MODEL and ignore_swappable:
|
|
continue
|
|
# Raise an error with a best-effort helpful message
|
|
# (only for the first issue). Error message should look like:
|
|
# "ValueError: Lookup failed for model referenced by
|
|
# field migrations.Book.author: migrations.Author"
|
|
msg = "Lookup failed for model referenced by field {field}: {model[0]}.{model[1]}"
|
|
raise ValueError(msg.format(field=operations[0][1], model=lookup_model))
|
|
else:
|
|
do_pending_lookups(model)
|
|
|
|
def clone(self):
|
|
"""
|
|
Return a clone of this registry, mainly used by the migration framework.
|
|
"""
|
|
clone = StateApps([], {})
|
|
clone.all_models = copy.deepcopy(self.all_models)
|
|
clone.app_configs = copy.deepcopy(self.app_configs)
|
|
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].models = OrderedDict()
|
|
self.app_configs[app_label].models[model._meta.model_name] = 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
|
|
self.clear_cache()
|
|
|
|
|
|
class ModelState(object):
|
|
"""
|
|
Represents a Django Model. We don't use the actual Model class
|
|
as it's not designed to have its options changed - instead, we
|
|
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 = force_text(name)
|
|
self.fields = fields
|
|
self.options = options or {}
|
|
self.bases = bases or (models.Model, )
|
|
self.managers = managers or []
|
|
# Sanity-check that fields is NOT a dict. It must be ordered.
|
|
if isinstance(self.fields, dict):
|
|
raise ValueError("ModelState.fields cannot be a dict - it must be a list of 2-tuples.")
|
|
# Sanity-check that fields are NOT already bound to a model.
|
|
for name, field in fields:
|
|
if hasattr(field, 'model'):
|
|
raise ValueError(
|
|
'ModelState.fields cannot be bound to a model - "%s" is.' % name
|
|
)
|
|
|
|
@cached_property
|
|
def name_lower(self):
|
|
return self.name.lower()
|
|
|
|
@classmethod
|
|
def from_model(cls, model, exclude_rels=False):
|
|
"""
|
|
Feed me a model, get a ModelState representing it out.
|
|
"""
|
|
# Deconstruct the fields
|
|
fields = []
|
|
for field in model._meta.local_fields:
|
|
if getattr(field, "rel", None) and exclude_rels:
|
|
continue
|
|
if isinstance(field, OrderWrt):
|
|
continue
|
|
name, path, args, kwargs = field.deconstruct()
|
|
field_class = import_string(path)
|
|
try:
|
|
fields.append((name, field_class(*args, **kwargs)))
|
|
except TypeError as e:
|
|
raise TypeError("Couldn't reconstruct field %s on %s.%s: %s" % (
|
|
name,
|
|
model._meta.app_label,
|
|
model._meta.object_name,
|
|
e,
|
|
))
|
|
if not exclude_rels:
|
|
for field in model._meta.local_many_to_many:
|
|
name, path, args, kwargs = field.deconstruct()
|
|
field_class = import_string(path)
|
|
try:
|
|
fields.append((name, field_class(*args, **kwargs)))
|
|
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))
|
|
else:
|
|
options[name] = model._meta.original_attrs[name]
|
|
# Force-convert all options to text_type (#23226)
|
|
options = cls.force_text_recursive(options)
|
|
# 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]
|
|
|
|
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(
|
|
(
|
|
"%s.%s" % (base._meta.app_label, base._meta.model_name)
|
|
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, six.string_types) or issubclass(base, models.Model)) for base in bases):
|
|
bases = (models.Model,)
|
|
|
|
# Constructs all managers on the model
|
|
managers = {}
|
|
|
|
def reconstruct_manager(mgr):
|
|
as_manager, manager_path, qs_path, args, kwargs = mgr.deconstruct()
|
|
if as_manager:
|
|
qs_class = import_string(qs_path)
|
|
instance = qs_class.as_manager()
|
|
else:
|
|
manager_class = import_string(manager_path)
|
|
instance = manager_class(*args, **kwargs)
|
|
# We rely on the ordering of the creation_counter of the original
|
|
# instance
|
|
managers[mgr.name] = (mgr.creation_counter, instance)
|
|
|
|
default_manager_name = model._default_manager.name
|
|
# Make sure the default manager is always the first
|
|
if model._default_manager.use_in_migrations:
|
|
reconstruct_manager(model._default_manager)
|
|
else:
|
|
# Force this manager to be the first and thus default
|
|
managers[default_manager_name] = (0, models.Manager())
|
|
# Sort all managers by their creation counter
|
|
for _, manager, _ in sorted(model._meta.managers):
|
|
if manager.name == '_base_manager' or not manager.use_in_migrations:
|
|
continue
|
|
reconstruct_manager(manager)
|
|
# Sort all managers by their creation counter but take only name and
|
|
# instance for further processing
|
|
managers = [
|
|
(name, instance) for name, (cc, instance) in
|
|
sorted(managers.items(), key=lambda v: v[1])
|
|
]
|
|
if managers == [(default_manager_name, models.Manager())]:
|
|
managers = []
|
|
|
|
# Construct the new ModelState
|
|
return cls(
|
|
model._meta.app_label,
|
|
model._meta.object_name,
|
|
fields,
|
|
options,
|
|
bases,
|
|
managers,
|
|
)
|
|
|
|
@classmethod
|
|
def force_text_recursive(cls, value):
|
|
if isinstance(value, six.string_types):
|
|
return smart_text(value)
|
|
elif isinstance(value, list):
|
|
return [cls.force_text_recursive(x) for x in value]
|
|
elif isinstance(value, tuple):
|
|
return tuple(cls.force_text_recursive(x) for x in value)
|
|
elif isinstance(value, set):
|
|
return set(cls.force_text_recursive(x) for x in value)
|
|
elif isinstance(value, dict):
|
|
return {
|
|
cls.force_text_recursive(k): cls.force_text_recursive(v)
|
|
for k, v in value.items()
|
|
}
|
|
return value
|
|
|
|
def construct_fields(self):
|
|
"Deep-clone the fields using deconstruction"
|
|
for name, field in self.fields:
|
|
_, path, args, kwargs = field.deconstruct()
|
|
field_class = import_string(path)
|
|
yield name, field_class(*args, **kwargs)
|
|
|
|
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):
|
|
"Returns an exact copy of this ModelState"
|
|
return self.__class__(
|
|
app_label=self.app_label,
|
|
name=self.name,
|
|
fields=list(self.construct_fields()),
|
|
options=dict(self.options),
|
|
bases=self.bases,
|
|
managers=list(self.construct_managers()),
|
|
)
|
|
|
|
def render(self, apps):
|
|
"Creates 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}
|
|
meta_contents.update(self.options)
|
|
meta = type(str("Meta"), tuple(), meta_contents)
|
|
# Then, work out our bases
|
|
try:
|
|
bases = tuple(
|
|
(apps.get_model(base) if isinstance(base, six.string_types) else base)
|
|
for base in self.bases
|
|
)
|
|
except LookupError:
|
|
raise InvalidBasesError("Cannot resolve one or more bases from %r" % (self.bases,))
|
|
# Turn fields into a dict for the body, add other bits
|
|
body = dict(self.construct_fields())
|
|
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(
|
|
str(self.name),
|
|
bases,
|
|
body,
|
|
)
|
|
|
|
def get_field_by_name(self, name):
|
|
for fname, field in self.fields:
|
|
if fname == name:
|
|
return field
|
|
raise ValueError("No field called %s on model %s" % (name, self.name))
|
|
|
|
def __repr__(self):
|
|
return "<ModelState: '%s.%s'>" % (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(self.fields, other.fields)) and
|
|
(self.options == other.options) and
|
|
(self.bases == other.bases) and
|
|
(self.managers == other.managers)
|
|
)
|
|
|
|
def __ne__(self, other):
|
|
return not (self == other)
|