Refs #7261 -- Made strings escaped by Django usable in third-party libs.
The changes in mark_safe and mark_for_escaping are straightforward. The
more tricky part is to handle correctly objects that implement __html__.
Historically escape() has escaped SafeData. Even if that doesn't seem a
good behavior, changing it would create security concerns. Therefore
support for __html__() was only added to conditional_escape() where this
concern doesn't exist.
Then using conditional_escape() instead of escape() in the Django
template engine makes it understand data escaped by other libraries.
Template filter |escape accounts for __html__() when it's available.
|force_escape forces the use of Django's HTML escaping implementation.
Here's why the change in render_value_in_context() is safe. Before Django
1.7 conditional_escape() was implemented as follows:
if isinstance(text, SafeData):
return text
else:
return escape(text)
render_value_in_context() never called escape() on SafeData. Therefore
replacing escape() with conditional_escape() doesn't change the
autoescaping logic as it was originally intended.
This change should be backported to Django 1.7 because it corrects a
feature added in Django 1.7.
Thanks mitsuhiko for the report.
mark_safe and mark_for_escaping should have been kept similar.
On Python 2 this change has no effect. On Python 3 it fixes the use case
shown in the regression test for mark_for_escaping, which used to raise
a TypeError. The regression test for mark_safe is just for completeness.
This reverts commit 2ee447fb5f.
That commit introduced a regression (#21882) and didn't really
do what it was supposed to: while it did delay the evaluation
of lazy objects passed to mark_safe(), they weren't actually
marked as such so they could end up being escaped twice.
Refs #21882.
The idea is that if an object implements __html__ which returns a string this is
used as HTML representation (eg: on escaping). If the object is a str or unicode
subclass and returns itself the object is a safe string type.
This is an updated patch based on jbalogh and ivank patches.
Iacopo Spalletti
Simon Charette
Tim Graham
Aymeric Augustin
Jon Dufresne
Alex Gaynor
Baptiste Mispelon
Unai Zalakain
Claude Paroz