From d75943cb42a82467977b0a213f44c191ba775ceb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michael=20Elsd=C3=B6rfer?= <michael@elsdoerfer.com>
Date: Wed, 2 Jan 2013 22:18:51 +0100
Subject: [PATCH] Refactor extension loading slightly.

---
 coffin/common.py            | 37 ++++++++++++++++---------------------
 coffin/template/__init__.py |  4 ++++
 2 files changed, 20 insertions(+), 21 deletions(-)

diff --git a/coffin/common.py b/coffin/common.py
index 32b509c..945d3e2 100644
--- a/coffin/common.py
+++ b/coffin/common.py
@@ -73,7 +73,6 @@ class CoffinEnvironment(Environment):
                 warnings.warn('Cannot translate loader: %s' % loader)
         return loaders
 
-
     def _get_templatelibs(self):
         """Return an iterable of template ``Library`` instances.
 
@@ -81,30 +80,35 @@ class CoffinEnvironment(Environment):
         register all libraries globally.
         """
         from django.conf import settings
-        from django.template import get_library, InvalidTemplateLibrary
+        from django.template import (
+            get_library, import_library, InvalidTemplateLibrary)
 
         libs = []
-        for a in settings.INSTALLED_APPS:
+        for app in settings.INSTALLED_APPS:
+            ns = app + '.templatetags'
             try:
-                path = __import__(a + '.templatetags', {}, {}, ['__file__']).__file__
+                path = __import__(ns, {}, {}, ['__file__']).__file__
                 path = os.path.dirname(path)  # we now have the templatetags/ directory
             except ImportError:
                 pass
             else:
-                for f in os.listdir(path):
-                    if f == '__init__.py' or f.startswith('.'):
+                for filename in os.listdir(path):
+                    if filename == '__init__.py' or filename.startswith('.'):
                         continue
 
-                    if f.endswith('.py'):
+                    if filename.endswith('.py'):
                         try:
-                            # TODO: will need updating when #6587 lands
-                            # libs.append(get_library(
-                            #     "django.templatetags.%s" % os.path.splitext(f)[0]))
-                            l = get_library(os.path.splitext(f)[0])
+                            module = "%s.%s" % (ns, os.path.splitext(filename)[0])
+                            l = import_library(module)
                             libs.append(l)
 
                         except InvalidTemplateLibrary:
                             pass
+
+        # In addition to loading application libraries, support a custom list
+        for libname in getattr(settings, 'JINJA2_DJANGO_TEMPLATETAG_LIBRARIES', ()):
+            libs.append(get_library(libname))
+
         return libs
 
     def _get_all_extensions(self):
@@ -168,19 +172,10 @@ class CoffinEnvironment(Environment):
         tests.update(from_setting('JINJA2_TESTS', True))
         filters.update(from_setting('JINJA2_FILTERS', True))
         globals.update(from_setting('JINJA2_GLOBALS'))
-        
 
         # Finally, add extensions defined in application's templatetag libraries
-        libraries = self._get_templatelibs()
-
-        # Load custom libraries.
-        from django.template import get_library
-        for libname in getattr(settings, 'JINJA2_DJANGO_TEMPLATETAG_LIBRARIES', ()):
-            libraries.append(get_library(libname))
-
-        for lib in libraries:
+        for lib in self._get_templatelibs():
             _load_lib(lib)
-            attrs.update(getattr(lib, 'jinja2_environment_attrs', {}))
 
         return dict(
             extensions=extensions,
diff --git a/coffin/template/__init__.py b/coffin/template/__init__.py
index 65c6d91..4dda1e1 100644
--- a/coffin/template/__init__.py
+++ b/coffin/template/__init__.py
@@ -88,6 +88,10 @@ def add_to_builtins(module_name):
     You can still use Django's own ``add_to_builtins`` to register
     directly with Django and bypass Coffin.
 
+    Once thing that is special about Coffin is that because {% load %}
+    is not supported in Coffin, *everything* it provides must be
+    registered through the builtins.
+
     TODO: Allow passing path to (or reference of) extensions and
     filters directly. This would make it easier to use this function
     with 3rd party Jinja extensions that do not know about Coffin and