diff --git a/docs/ref/templates/builtins.txt b/docs/ref/templates/builtins.txt index 291abcb8cc..41bf683c22 100644 --- a/docs/ref/templates/builtins.txt +++ b/docs/ref/templates/builtins.txt @@ -619,6 +619,13 @@ including it. This example produces the output ``"Hello, John"``: See also: ``{% ssi %}``. +.. note:: + The :ttag:`include` tag should be considered as an implementation of + "render this subtemplate and include the HTML", not as "parse this + subtemplate and include its contents as if it were part of the parent". + This means that there is no shared state between included templates -- + each include is a completely independent rendering process. + .. templatetag:: load load diff --git a/docs/releases/1.2.txt b/docs/releases/1.2.txt index 0d61d1893f..31b95e4ace 100644 --- a/docs/releases/1.2.txt +++ b/docs/releases/1.2.txt @@ -230,6 +230,34 @@ party packages, or from your own code, you should ensure that the information, see :ref:`template tag thread safety considerations`. +You may also need to update your templates if you were relying on the +implementation of Django's template tags *not* being thread safe. The +:ttag:`cycle` tag is the most likely to be affected in this way, +especially when used in conjunction with the :ttag:`include` tag. +Consider the following template fragment:: + + {% for object in object_list %} + {% include "subtemplate.html" %} + {% endfor %} + +with a ``subtemplate.html`` that reads:: + + {% cycle 'even' 'odd' %} + +Using the non thread-safe, pre-Django 1.2 renderer, this would output:: + + even odd even odd ... + +Using the thread-safe Django 1.2 renderer, you will instead get:: + + even even even even ... + +This is because the each rendering of the :ttag:`include` tag is an +independent rendering. When the :ttag:`cycle` tag was not thread safe, +the state of the :ttag:`cycle` tag would leak between multiple renderings +of the same :ttag:`include`. Now that the :ttag:`cycle` tag is thread safe, +this leakage no longer occurs. + Test runner exit status code ----------------------------