Fixed #25697 -- Made default error views error when passed a nonexistent template_name.

django/views/defaults.py

@@ -4,12 +4,17 @@ from django.utils import six
 from django.utils.encoding import force_text
 from django.views.decorators.csrf import requires_csrf_token
 
+ERROR_404_TEMPLATE_NAME = '404.html'
+ERROR_403_TEMPLATE_NAME = '403.html'
+ERROR_400_TEMPLATE_NAME = '400.html'
+ERROR_500_TEMPLATE_NAME = '500.html'
+
 
 # This can be called when CsrfViewMiddleware.process_view has not run,
 # therefore need @requires_csrf_token in case the template needs
 # {% csrf_token %}.
 @requires_csrf_token
-def page_not_found(request, exception, template_name='404.html'):
+def page_not_found(request, exception, template_name=ERROR_404_TEMPLATE_NAME):
     """
     Default 404 handler.
 
@@ -40,6 +45,9 @@ def page_not_found(request, exception, template_name='404.html'):
         body = template.render(context, request)
         content_type = None             # Django will use DEFAULT_CONTENT_TYPE
     except TemplateDoesNotExist:
+        if template_name != ERROR_404_TEMPLATE_NAME:
+            # Reraise if it's a missing custom template.
+            raise
         template = Engine().from_string(
             '<h1>Not Found</h1>'
             '<p>The requested URL {{ request_path }} was not found on this server.</p>')
@@ -49,7 +57,7 @@ def page_not_found(request, exception, template_name='404.html'):
 
 
 @requires_csrf_token
-def server_error(request, template_name='500.html'):
+def server_error(request, template_name=ERROR_500_TEMPLATE_NAME):
     """
     500 error handler.
 
@@ -59,12 +67,15 @@ def server_error(request, template_name='500.html'):
     try:
         template = loader.get_template(template_name)
     except TemplateDoesNotExist:
+        if template_name != ERROR_500_TEMPLATE_NAME:
+            # Reraise if it's a missing custom template.
+            raise
         return http.HttpResponseServerError('<h1>Server Error (500)</h1>', content_type='text/html')
     return http.HttpResponseServerError(template.render())
 
 
 @requires_csrf_token
-def bad_request(request, exception, template_name='400.html'):
+def bad_request(request, exception, template_name=ERROR_400_TEMPLATE_NAME):
     """
     400 error handler.
 
@@ -74,6 +85,9 @@ def bad_request(request, exception, template_name='400.html'):
     try:
         template = loader.get_template(template_name)
     except TemplateDoesNotExist:
+        if template_name != ERROR_400_TEMPLATE_NAME:
+            # Reraise if it's a missing custom template.
+            raise
         return http.HttpResponseBadRequest('<h1>Bad Request (400)</h1>', content_type='text/html')
     # No exception content is passed to the template, to not disclose any sensitive information.
     return http.HttpResponseBadRequest(template.render())
@@ -83,7 +97,7 @@ def bad_request(request, exception, template_name='400.html'):
 # therefore need @requires_csrf_token in case the template needs
 # {% csrf_token %}.
 @requires_csrf_token
-def permission_denied(request, exception, template_name='403.html'):
+def permission_denied(request, exception, template_name=ERROR_403_TEMPLATE_NAME):
     """
     Permission denied (403) handler.
 
@@ -96,6 +110,9 @@ def permission_denied(request, exception, template_name='403.html'):
     try:
         template = loader.get_template(template_name)
     except TemplateDoesNotExist:
+        if template_name != ERROR_403_TEMPLATE_NAME:
+            # Reraise if it's a missing custom template.
+            raise
         return http.HttpResponseForbidden('<h1>403 Forbidden</h1>', content_type='text/html')
     return http.HttpResponseForbidden(
         template.render(request=request, context={'exception': force_text(exception)})