Stopped iterating on INSTALLED_APPS.

Used the app cache's get_app_configs() method instead.

11 files changed, 51 insertions, 45 deletions

diff --git a/django/contrib/staticfiles/finders.py b/django/contrib/staticfiles/finders.py
index cf5eb4f85b..cadc8bffa7 100644
--- a/django/contrib/staticfiles/finders.py
+++ b/django/contrib/staticfiles/finders.py
@@ -2,6 +2,7 @@ from collections import OrderedDict
 import os
 
 from django.conf import settings
+from django.core.apps import app_cache
 from django.core.exceptions import ImproperlyConfigured
 from django.core.files.storage import default_storage, Storage, FileSystemStorage
 from django.utils.functional import empty, LazyObject
@@ -116,10 +117,11 @@ class AppDirectoriesFinder(BaseFinder):
     def __init__(self, apps=None, *args, **kwargs):
         # The list of apps that are handled
         self.apps = []
-        # Mapping of app module paths to storage instances
+        # Mapping of app names to storage instances
         self.storages = OrderedDict()
         if apps is None:
-            apps = settings.INSTALLED_APPS
+            app_configs = app_cache.get_app_configs()
+            apps = [app_config.name for app_config in app_configs]
         for app in apps:
             app_storage = self.storage_class(app)
             if os.path.isdir(app_storage.location):
diff --git a/django/core/management/__init__.py b/django/core/management/__init__.py
index 0b47e179db..a7d074e149 100644
--- a/django/core/management/__init__.py
+++ b/django/core/management/__init__.py
@@ -5,6 +5,7 @@ from optparse import OptionParser, NO_DEFAULT
 import os
 import sys
 
+from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.core.management.base import BaseCommand, CommandError, handle_default_options
 from django.core.management.color import color_style
@@ -106,13 +107,19 @@ def get_commands():
         _commands = dict((name, 'django.core') for name in find_commands(__path__[0]))
 
         # Find the installed apps
-        from django.conf import settings
         try:
-            apps = settings.INSTALLED_APPS
+            settings.INSTALLED_APPS
         except ImproperlyConfigured:
-            # Still useful for commands that do not require functional settings,
-            # like startproject or help
+            # Still useful for commands that do not require functional
+            # settings, like startproject or help.
             apps = []
+        else:
+            # Populate the app cache outside of the try/except block to avoid
+            # catching ImproperlyConfigured errors that aren't caused by the
+            # absence of a settings module.
+            from django.core.apps import app_cache
+            app_configs = app_cache.get_app_configs()
+            apps = [app_config.name for app_config in app_configs]
 
         # Find and load the management module for each installed app.
         for app_name in apps:
@@ -339,9 +346,10 @@ class ManagementUtility(object):
             elif cwords[0] in ('dumpdata', 'sql', 'sqlall', 'sqlclear',
                     'sqlcustom', 'sqlindexes', 'sqlsequencereset', 'test'):
                 try:
-                    from django.conf import settings
+                    from django.core.apps import app_cache
+                    app_configs = app_cache.get_app_configs()
                     # Get the last part of the dotted path as the app name.
-                    options += [(a.split('.')[-1], 0) for a in settings.INSTALLED_APPS]
+                    options += [(app_config.label, 0) for app_config in app_configs]
                 except ImportError:
                     # Fail silently if DJANGO_SETTINGS_MODULE isn't set. The
                     # user will find out once they execute the command.
diff --git a/django/core/management/commands/flush.py b/django/core/management/commands/flush.py
index 562147e403..f13e948ae5 100644
--- a/django/core/management/commands/flush.py
+++ b/django/core/management/commands/flush.py
@@ -2,7 +2,6 @@ import sys
 from importlib import import_module
 from optparse import make_option
 
-from django.conf import settings
 from django.core.apps import app_cache
 from django.db import connections, router, transaction, DEFAULT_DB_ALIAS
 from django.core.management import call_command
@@ -42,9 +41,9 @@ class Command(NoArgsCommand):
 
         # Import the 'management' module within each installed app, to register
         # dispatcher events.
-        for app_name in settings.INSTALLED_APPS:
+        for app_config in app_cache.get_app_configs():
             try:
-                import_module('.management', app_name)
+                import_module('.management', app_config.name)
             except ImportError:
                 pass
 
diff --git a/django/core/management/commands/migrate.py b/django/core/management/commands/migrate.py
index b607e8ee43..c99f26aa0c 100644
--- a/django/core/management/commands/migrate.py
+++ b/django/core/management/commands/migrate.py
@@ -6,7 +6,6 @@ from importlib import import_module
 import itertools
 import traceback
 
-from django.conf import settings
 from django.core.apps import app_cache
 from django.core.management import call_command
 from django.core.management.base import BaseCommand, CommandError
@@ -47,9 +46,9 @@ class Command(BaseCommand):
 
         # Import the 'management' module within each installed app, to register
         # dispatcher events.
-        for app_name in settings.INSTALLED_APPS:
-            if module_has_submodule(import_module(app_name), "management"):
-                import_module('.management', app_name)
+        for app_config in app_cache.get_app_configs():
+            if module_has_submodule(app_config.app_module, "management"):
+                import_module('.management', app_config.name)
 
         # Get the database we're operating from
         db = options.get('database')
diff --git a/django/template/base.py b/django/template/base.py
index c314637c42..7098ea60f8 100644
--- a/django/template/base.py
+++ b/django/template/base.py
@@ -6,6 +6,7 @@ from importlib import import_module
 from inspect import getargspec, getcallargs
 
 from django.conf import settings
+from django.core.apps import app_cache
 from django.template.context import (BaseContext, Context, RequestContext,  # NOQA: imported for backwards compatibility
     ContextPopException)
 from django.utils.itercompat import is_iterable
@@ -1302,9 +1303,12 @@ def get_templatetags_modules():
         # Populate list once per process. Mutate the local list first, and
         # then assign it to the global name to ensure there are no cases where
         # two threads try to populate it simultaneously.
-        for app_module in ['django'] + list(settings.INSTALLED_APPS):
+
+        templatetags_modules_candidates = ['django.templatetags']
+        templatetags_modules_candidates += ['%s.templatetags' % app_config.name
+            for app_config in app_cache.get_app_configs()]
+        for templatetag_module in templatetags_modules_candidates:
             try:
-                templatetag_module = '%s.templatetags' % app_module
                 import_module(templatetag_module)
                 _templatetags_modules.append(templatetag_module)
             except ImportError:
diff --git a/django/template/loaders/app_directories.py b/django/template/loaders/app_directories.py
index 4f8ddfccac..90baa34c7a 100644
--- a/django/template/loaders/app_directories.py
+++ b/django/template/loaders/app_directories.py
@@ -3,12 +3,11 @@ Wrapper for loading templates from "templates" directories in INSTALLED_APPS
 packages.
 """
 
-from importlib import import_module
 import os
 import sys
 
 from django.conf import settings
-from django.core.exceptions import ImproperlyConfigured
+from django.core.apps import app_cache
 from django.template.base import TemplateDoesNotExist
 from django.template.loader import BaseLoader
 from django.utils._os import safe_join
@@ -18,12 +17,8 @@ from django.utils import six
 if six.PY2:
     fs_encoding = sys.getfilesystemencoding() or sys.getdefaultencoding()
 app_template_dirs = []
-for app in settings.INSTALLED_APPS:
-    try:
-        mod = import_module(app)
-    except ImportError as e:
-        raise ImproperlyConfigured('ImportError %s: %s' % (app, e.args[0]))
-    template_dir = os.path.join(os.path.dirname(mod.__file__), 'templates')
+for app_config in app_cache.get_app_configs():
+    template_dir = os.path.join(app_config.path, 'templates')
     if os.path.isdir(template_dir):
         if six.PY2:
             template_dir = template_dir.decode(fs_encoding)
diff --git a/django/template/loaders/eggs.py b/django/template/loaders/eggs.py
index 04e4f73b7b..e9b46b15de 100644
--- a/django/template/loaders/eggs.py
+++ b/django/template/loaders/eggs.py
@@ -7,6 +7,7 @@ except ImportError:
     resource_string = None
 
 from django.conf import settings
+from django.core.apps import app_cache
 from django.template.base import TemplateDoesNotExist
 from django.template.loader import BaseLoader
 from django.utils import six
@@ -23,12 +24,12 @@ class Loader(BaseLoader):
         """
         if resource_string is not None:
             pkg_name = 'templates/' + template_name
-            for app in settings.INSTALLED_APPS:
+            for app_config in app_cache.get_app_configs():
                 try:
-                    resource = resource_string(app, pkg_name)
+                    resource = resource_string(app_config.name, pkg_name)
                 except Exception:
                     continue
                 if six.PY2:
                     resource = resource.decode(settings.FILE_CHARSET)
-                return (resource, 'egg:%s:%s' % (app, pkg_name))
+                return (resource, 'egg:%s:%s' % (app_config.name, pkg_name))
         raise TemplateDoesNotExist(template_name)
diff --git a/django/utils/autoreload.py b/django/utils/autoreload.py
index 1913317822..05ffb12f74 100644
--- a/django/utils/autoreload.py
+++ b/django/utils/autoreload.py
@@ -37,9 +37,8 @@ import time
 import traceback
 
 from django.conf import settings
+from django.core.apps import app_cache
 from django.core.signals import request_finished
-from django.utils._os import upath
-from importlib import import_module
 try:
     from django.utils.six.moves import _thread as thread
 except ImportError:
@@ -91,10 +90,8 @@ def gen_filenames():
         basedirs = [os.path.join(os.path.dirname(os.path.dirname(__file__)),
                                  'conf', 'locale'),
                     'locale']
-        for appname in reversed(settings.INSTALLED_APPS):
-            app = import_module(appname)
-            basedirs.append(os.path.join(os.path.dirname(upath(app.__file__)),
-                                         'locale'))
+        for app_config in reversed(list(app_cache.get_app_configs())):
+            basedirs.append(os.path.join(app_config.path, 'locale'))
         basedirs.extend(settings.LOCALE_PATHS)
         basedirs = [os.path.abspath(basedir) for basedir in basedirs
                     if os.path.isdir(basedir)]
diff --git a/django/utils/module_loading.py b/django/utils/module_loading.py
index 0c6bad2a7b..8d95fc00a3 100644
--- a/django/utils/module_loading.py
+++ b/django/utils/module_loading.py
@@ -58,18 +58,17 @@ def autodiscover_modules(*args, **kwargs):
     registry. This register_to object must have a _registry instance variable
     to access it.
     """
-    from django.conf import settings
+    from django.core.apps import app_cache
 
     register_to = kwargs.get('register_to')
-    for app in settings.INSTALLED_APPS:
-        mod = import_module(app)
+    for app_config in app_cache.get_app_configs():
         # Attempt to import the app's module.
         try:
             if register_to:
                 before_import_registry = copy.copy(register_to._registry)
 
             for module_to_search in args:
-                import_module('%s.%s' % (app, module_to_search))
+                import_module('%s.%s' % (app_config.name, module_to_search))
         except:
             # Reset the model registry to the state before the last import as
             # this import will have to reoccur on the next request and this
@@ -81,7 +80,7 @@ def autodiscover_modules(*args, **kwargs):
             # Decide whether to bubble up this error. If the app just
             # doesn't have an admin module, we can ignore the error
             # attempting to import it, otherwise we want it to bubble up.
-            if module_has_submodule(mod, module_to_search):
+            if module_has_submodule(app_config.app_module, module_to_search):
                 raise
 
 
diff --git a/django/utils/translation/trans_real.py b/django/utils/translation/trans_real.py
index e547800b92..3ed6371966 100644
--- a/django/utils/translation/trans_real.py
+++ b/django/utils/translation/trans_real.py
@@ -7,10 +7,10 @@ import os
 import re
 import sys
 import gettext as gettext_module
-from importlib import import_module
 from threading import local
 import warnings
 
+from django.core.apps import app_cache
 from django.dispatch import receiver
 from django.test.signals import setting_changed
 from django.utils.encoding import force_str, force_text
@@ -179,10 +179,8 @@ def translation(language):
                     res.merge(t)
             return res
 
-        for appname in reversed(settings.INSTALLED_APPS):
-            app = import_module(appname)
-            apppath = os.path.join(os.path.dirname(upath(app.__file__)), 'locale')
-
+        for app_config in reversed(list(app_cache.get_app_configs())):
+            apppath = os.path.join(app_config.path, 'locale')
             if os.path.isdir(apppath):
                 res = _merge(apppath)
 
diff --git a/django/views/i18n.py b/django/views/i18n.py
index 751905efaf..2f0c89a037 100644
--- a/django/views/i18n.py
+++ b/django/views/i18n.py
@@ -5,6 +5,7 @@ import gettext as gettext_module
 
 from django import http
 from django.conf import settings
+from django.core.apps import app_cache
 from django.template import Context, Template
 from django.utils.translation import check_for_language, to_locale, get_language
 from django.utils.encoding import smart_text
@@ -187,7 +188,10 @@ def render_javascript_catalog(catalog=None, plural=None):
 
 def get_javascript_catalog(locale, domain, packages):
     default_locale = to_locale(settings.LANGUAGE_CODE)
-    packages = [p for p in packages if p == 'django.conf' or p in settings.INSTALLED_APPS]
+    app_configs = app_cache.get_app_configs()
+    allowable_packages = set(app_config.name for app_config in app_configs)
+    allowable_packages.add('django.conf')
+    packages = [p for p in packages if p in allowable_packages]
     t = {}
     paths = []
     en_selected = locale.startswith('en')