Simplified Apps.get_model and added AppConfig.get_model.

Documented them as public APIs.

django/apps/base.py

@@ -109,6 +109,23 @@ class AppConfig(object):
             # Entry is a path to an app module.
             return cls(entry, module)
 
+    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.
+
+        This method assumes that apps.populate_models() has run.
+        """
+        if self.models is None:
+            raise LookupError(
+                "App '%s' doesn't have any models." % self.label)
+        try:
+            return self.models[model_name.lower()]
+        except KeyError:
+            raise LookupError(
+                "App '%s' doesn't have a '%s' model." % (self.label, model_name))
+
     def import_models(self, all_models):
         # Dictionary of models for this app, primarily maintained in the
         # 'all_models' attribute of the Apps this AppConfig is attached to.

django/apps/registry.py

@@ -185,7 +185,7 @@ class Apps(object):
         if app_config is None:
             raise LookupError("No installed app with label '%s'." % app_label)
         if only_with_models_module and app_config.models_module is None:
-            raise LookupError("App with label '%s' doesn't have a models module." % app_label)
+            raise LookupError("App '%s' doesn't have a models module." % app_label)
         return app_config
 
     # This method is performance-critical at least for Django's test suite.
@@ -242,21 +242,20 @@ class Apps(object):
             )
         return model_list
 
-    def get_model(self, app_label, model_name, only_installed=True):
+    def get_model(self, app_label, model_name):
         """
-        Returns the model matching the given app_label and case-insensitive
-        model_name.
+        Returns the model matching the given app_label and model_name.
 
-        Returns None if no model is found.
+        model_name is case-insensitive.
+
+        Returns None if no application exists with this label, or no model
+        exists with this name in the application.
         """
-        if not self.master:
-            only_installed = False
         self.populate_models()
-        if only_installed:
-            app_config = self.app_configs.get(app_label)
-            if app_config is None:
-                return None
-        return self.all_models[app_label].get(model_name.lower())
+        try:
+            return self.get_app_config(app_label).get_model(model_name.lower())
+        except LookupError:
+            return None
 
     def register_model(self, app_label, model):
         # Since this method is called when models are imported, it cannot
@@ -286,10 +285,11 @@ class Apps(object):
 
     def get_registered_model(self, app_label, model_name):
         """
-        Returns the model class if one is registered and None otherwise.
+        Similar to get_model(), but doesn't require that an app exists with
+        the given app_label.
 
         It's safe to call this method at import time, even while the registry
-        is being populated. It returns False for models that aren't loaded yet.
+        is being populated. It returns None for models that aren't loaded yet.
         """
         return self.all_models[app_label].get(model_name.lower())
 

docs/ref/applications.txt

@@ -153,6 +153,15 @@ Read-only attributes
 
     It may be ``None`` if the application doesn't contain a ``models`` module.
 
+Methods
+-------
+
+.. method:: AppConfig.get_model(model_name)
+
+    Returns the :class:`~django.db.models.Model` with the given
+    ``model_name``. Raises :exc:`~exceptions.LookupError` if no such model
+    exists. ``model_name`` is case-insensitive.
+
 Application registry
 ====================
 
@@ -189,3 +198,9 @@ Application registry
     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``
+    and ``model_name``. Returns ``None`` if no such application or model
+    exists. ``model_name`` is case-insensitive.