Switch the url and ssi template tags to the "future" behavior

[Aymeric Augustin]

As explained in the ​deprecation timeline.

[Claude Paroz]

Remove old-style url and ssi template tags

[Ramiro Morales]

Patch is OK.

My only concern about which Id like to have a clear path is about the lifetime of the future template tag library, or more precisely the lifetime of the ssi and url template tags contained in it. Are we going to leave them there ad do-nothing shims forever? Are we goiung to demove them now? are we going to create a deprecation cycle for these kind of tags?

[Claude Paroz]

Leaving them for ever might be problematic, should we need a new deprecation process in the future with these tags. Removing them right now doesn't seem a nice option, as it would break templates loading the future library in 1.5. The following patch adds a note to the 2.0 section of the deprecation timeline. The other viable option would be to start a new standard deprecation path for those two tags when loaded from the future library.

[Claude Paroz]

Same patch with 2.0 deprecation note

[Jannis Leidel]

I'd be for leaving the future template tag library in place, including the shims for those template tags as it really was supposed to work like Python's __future__.

According to ​http://docs.python.org/library/__future__.html: "No feature description will ever be deleted from future"

So +1 for deprecating it in 2.0

[Claude Paroz]

In [17934]:

Fixed #18037 -- Changed behaviour of url and ssi template tags to the new syntax, as per official deprecation timeline. Thanks Ramiro Morales and Jannis Leidel for the review.

[Claude Paroz]

In [17935]:

Removed some leftover references to old-syntax ssi template tag tests. Refs #18037.