Fixed #19878 -- Deprecated TemplateView passing URL kwargs into context.

1 files changed, 26 insertions, 4 deletions

diff --git a/django/views/generic/base.py b/django/views/generic/base.py
index 3dd957d8f8..ea5baca08d 100644
--- a/django/views/generic/base.py
+++ b/django/views/generic/base.py
@@ -1,4 +1,5 @@
 import logging
+import warnings
 from functools import update_wrapper
 
 from django.core.exceptions import ImproperlyConfigured
@@ -9,6 +10,8 @@ from django.http import (
 from django.template.response import TemplateResponse
 from django.urls import reverse
 from django.utils.decorators import classonlymethod
+from django.utils.deprecation import RemovedInDjango40Warning
+from django.utils.functional import SimpleLazyObject
 
 logger = logging.getLogger('django.request')
 
@@ -152,14 +155,33 @@ class TemplateResponseMixin:
 
 
 class TemplateView(TemplateResponseMixin, ContextMixin, View):
-    """
-    Render a template. Pass keyword arguments from the URLconf to the context.
-    """
+    """Render a template."""
     def get(self, request, *args, **kwargs):
-        context = self.get_context_data(**kwargs)
+        # RemovedInDjango40Warning: when the deprecation ends, replace with:
+        #   context = self.get_context_data()
+        context_kwargs = _wrap_url_kwargs_with_deprecation_warning(kwargs)
+        context = self.get_context_data(**context_kwargs)
         return self.render_to_response(context)
 
 
+# RemovedInDjango40Warning
+def _wrap_url_kwargs_with_deprecation_warning(url_kwargs):
+    context_kwargs = {}
+    for key, value in url_kwargs.items():
+        # Bind into function closure.
+        @SimpleLazyObject
+        def access_value(key=key, value=value):
+            warnings.warn(
+                'TemplateView passing URL kwargs to the context is '
+                'deprecated. Reference %s in your template through '
+                'view.kwargs instead.' % key,
+                RemovedInDjango40Warning, stacklevel=2,
+            )
+            return value
+        context_kwargs[key] = access_value
+    return context_kwargs
+
+
 class RedirectView(View):
     """Provide a redirect on any GET request."""
     permanent = False