diff --git a/django/apps/config.py b/django/apps/config.py
index dd1018b50a..9cfe4858aa 100644
--- a/django/apps/config.py
+++ b/django/apps/config.py
@@ -1,7 +1,7 @@
from importlib import import_module
import os
-from django.core.exceptions import ImproperlyConfigured
+from django.core.exceptions import AppRegistryNotReady, ImproperlyConfigured
from django.utils.module_loading import module_has_submodule
from django.utils._os import upath
@@ -139,15 +139,21 @@ class AppConfig(object):
# Entry is a path to an app config class.
return cls(app_name, app_module)
+ def check_models_ready(self):
+ """
+ Raises an exception if models haven't been imported yet.
+ """
+ if self.models is None:
+ raise AppRegistryNotReady(
+ "Models for app '%s' haven't been imported yet." % self.label)
+
def get_model(self, model_name):
"""
Returns the model with the given case-insensitive model_name.
Raises LookupError if no model exists with this name.
"""
- if self.models is None:
- raise LookupError(
- "App '%s' doesn't have any models." % self.label)
+ self.check_models_ready()
try:
return self.models[model_name.lower()]
except KeyError:
@@ -169,6 +175,7 @@ class AppConfig(object):
Set the corresponding keyword argument to True to include such models.
Keyword arguments aren't documented; they're a private API.
"""
+ self.check_models_ready()
for model in self.models.values():
if model._deferred and not include_deferred:
continue
diff --git a/django/apps/registry.py b/django/apps/registry.py
index 492a97f603..57bdc3edb2 100644
--- a/django/apps/registry.py
+++ b/django/apps/registry.py
@@ -43,7 +43,7 @@ class Apps(object):
self.stored_app_configs = []
# Whether the registry is populated.
- self.ready = False
+ self.apps_ready = self.models_ready = self.ready = False
# Lock for thread-safe population.
self._lock = threading.Lock()
@@ -100,29 +100,41 @@ class Apps(object):
"Application names aren't unique, "
"duplicates: %s" % ", ".join(duplicates))
+ self.apps_ready = True
+
# Load models.
for app_config in self.app_configs.values():
all_models = self.all_models[app_config.label]
app_config.import_models(all_models)
self.clear_cache()
- self.ready = True
+
+ self.models_ready = True
for app_config in self.get_app_configs():
app_config.ready()
- def check_ready(self):
+ self.ready = True
+
+ def check_apps_ready(self):
"""
- Raises an exception if the registry isn't ready.
+ Raises an exception if all apps haven't been imported yet.
"""
- if not self.ready:
- raise AppRegistryNotReady()
+ if not self.apps_ready:
+ raise AppRegistryNotReady("Apps aren't loaded yet.")
+
+ def check_models_ready(self):
+ """
+ Raises an exception if all models haven't been imported yet.
+ """
+ if not self.models_ready:
+ raise AppRegistryNotReady("Models aren't loaded yet.")
def get_app_configs(self):
"""
Imports applications and returns an iterable of app configs.
"""
- self.check_ready()
+ self.check_apps_ready()
return self.app_configs.values()
def get_app_config(self, app_label):
@@ -131,7 +143,7 @@ class Apps(object):
Raises LookupError if no application exists with this label.
"""
- self.check_ready()
+ self.check_apps_ready()
try:
return self.app_configs[app_label]
except KeyError:
@@ -153,7 +165,7 @@ class Apps(object):
Set the corresponding keyword argument to True to include such models.
"""
- self.check_ready()
+ self.check_models_ready()
if app_mod:
warnings.warn(
"The app_mod argument of get_models is deprecated.",
@@ -184,7 +196,7 @@ class Apps(object):
model exists with this name in the application. Raises ValueError if
called with a single argument that doesn't contain exactly one dot.
"""
- self.check_ready()
+ self.check_models_ready()
if model_name is None:
app_label, model_name = app_label.split('.')
return self.get_app_config(app_label).get_model(model_name.lower())
@@ -207,10 +219,8 @@ class Apps(object):
Checks whether an application with this name exists in the registry.
app_name is the full name of the app eg. 'django.contrib.admin'.
-
- It's safe to call this method at import time, even while the registry
- is being populated. It returns False for apps that aren't loaded yet.
"""
+ self.check_apps_ready()
return any(ac.name == app_name for ac in self.app_configs.values())
def get_containing_app_config(self, object_name):
@@ -221,10 +231,10 @@ class Apps(object):
Returns the app config for the inner application in case of nesting.
Returns None if the object isn't in any registered app config.
-
- It's safe to call this method at import time, even while the registry
- is being populated.
"""
+ # In Django 1.7 and 1.8, it's allowed to call this method at import
+ # time, even while the registry is being populated. In Django 1.9 and
+ # later, that should be forbidden with `self.check_apps_ready()`.
candidates = []
for app_config in self.app_configs.values():
if object_name.startswith(app_config.name):
@@ -297,10 +307,11 @@ class Apps(object):
imports safely (eg. that could lead to registering listeners twice),
models are registered when they're imported and never removed.
"""
- self.check_ready()
+ if not self.ready:
+ raise AppRegistryNotReady("App registry isn't ready yet.")
self.stored_app_configs.append(self.app_configs)
self.app_configs = OrderedDict()
- self.ready = False
+ self.apps_ready = self.models_ready = self.ready = False
self.clear_cache()
self.populate(installed)
@@ -309,7 +320,7 @@ class Apps(object):
Cancels a previous call to set_installed_apps().
"""
self.app_configs = self.stored_app_configs.pop()
- self.ready = True
+ self.apps_ready = self.models_ready = self.ready = True
self.clear_cache()
def clear_cache(self):
@@ -402,7 +413,7 @@ class Apps(object):
warnings.warn(
"[a.path for a in get_app_configs()] supersedes get_app_paths().",
RemovedInDjango19Warning, stacklevel=2)
- self.check_ready()
+ self.check_apps_ready()
app_paths = []
for app in self.get_apps():
app_paths.append(self._get_app_path(app))
diff --git a/docs/ref/applications.txt b/docs/ref/applications.txt
index a7590b899d..f1da87a1fd 100644
--- a/docs/ref/applications.txt
+++ b/docs/ref/applications.txt
@@ -301,10 +301,6 @@ Application registry
Checks whether an application with the given name exists in the registry.
``app_name`` is the full name of the app, e.g. ``'django.contrib.admin'``.
- Unlike :meth:`~django.apps.apps.get_app_config`, this method can be called
- safely at import time. If the registry is still being populated, it may
- return ``False``, even though the app will become available later.
-
.. method:: apps.get_model(app_label, model_name)
Returns the :class:`~django.db.models.Model` with the given ``app_label``
@@ -365,6 +361,9 @@ processes all applications in the order of :setting:`INSTALLED_APPS`.
the order of :setting:`INSTALLED_APPS`, it's strongly recommended not
import any models at this stage.
+ Once this stage completes, APIs that operate of application configurations
+ such as :meth:`~apps.get_app_config()` become usable.
+
#. Then Django attempts to import the ``models`` submodule of each application,
if there is one.
@@ -372,6 +371,9 @@ processes all applications in the order of :setting:`INSTALLED_APPS`.
``models/__init__.py``. Otherwise, the application registry may not be fully
populated at this point, which could cause the ORM to malfunction.
+ Once this stage completes, APIs that operate on models such as
+ :meth:`~apps.get_model()` become usable.
+
#. Finally Django runs the :meth:`~AppConfig.ready()` method of each application
configuration.