Remove add_to_builtins() call from init, need explicit setup in Djang…

…o 1.9

README.rst

@@ -30,6 +30,29 @@ Add the module to the installed apps::
         'debugtools',
     )
 
+As of Django 1.9, either use ``{% load debugtools_tags %}`` or add the following to the settings:
+
+.. code-block:: python
+
+    TEMPLATES = [
+        {
+            'BACKEND': 'django.template.backends.django.DjangoTemplates',
+            'DIRS': [],
+            'APP_DIRS': True,
+            'OPTIONS': {
+                'context_processors': [
+                    'django.template.context_processors.debug',
+                    'django.template.context_processors.request',
+                    # ...
+                ],
+               'builtins': [                                     # Add this section
+                    "debugtools.templatetags.debugtools_tags",   # Add this line
+                ],
+            },
+        },
+    ]
+
+
 Features
 --------
 

debugtools/__init__.py

@@ -3,12 +3,14 @@
 
 VERSION = (1, 4)
 
-# Make sure the ``{% print %}`` is always available, even without a {% load debug_tags %} call.
-# **NOTE** this uses the undocumented, unofficial add_to_builtins() call. It's not promoted
-# by Django developers because it's better to be explicit with a {% load .. %} in the templates.
-#
-# This function is used here nevertheless because the {% print %} tag is a debugging aid,
-# and not a tag that should remain permanently in your templates. Convenience is preferred here.
-#
-from django.template.base import add_to_builtins
-add_to_builtins("debugtools.templatetags.debug_tags")
+import django
+if django.VERSION < (1,9):
+    # Make sure the ``{% print %}`` is always available, even without a {% load debugtools_tags %} call.
+    # This feature is no longer available in Django 1.9, which adds an explicit configuration for it:
+    # see: https://docs.djangoproject.com/en/1.9/releases/1.9/#django-template-base-add-to-builtins-is-removed
+    #
+    # This function is used here because the {% print %} tag is a debugging aid,
+    # and not a tag that should remain permanently in your templates. Convenience is preferred here.
+    #
+    from django.template.base import add_to_builtins
+    add_to_builtins("debugtools.templatetags.debug_tags")