Ensure render_to_string leaves the context instance stack in the state it was originally passed in.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15591 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 9 insertions, 5 deletions

diff --git a/django/template/loader.py b/django/template/loader.py
index 279d8e86fe..e58dc3231d 100644
--- a/django/template/loader.py
+++ b/django/template/loader.py
@@ -179,11 +179,15 @@ def render_to_string(template_name, dictionary=None, context_instance=None):
         t = select_template(template_name)
     else:
         t = get_template(template_name)
-    if context_instance:
-        context_instance.update(dictionary)
-    else:
-        context_instance = Context(dictionary)
-    return t.render(context_instance)
+    if not context_instance:
+        return t.render(Context(dictionary))
+    # Add the dictionary to the context stack, ensuring it gets removed again
+    # to keep the context_instance in the same state it started in.
+    context_instance.update(dictionary)
+    try:
+        return t.render(context_instance)
+    finally:
+        context_instance.pop()
 
 def select_template(template_name_list):
     "Given a list of template names, returns the first that can be loaded."