remove admin's reliance on TEMPLATE_STRING_IF_INVALID set to empty string

[Jeff Bauer <jbauer@…>]

Refactor the way TEMPLATE_STRING_IF_INVALID works, rather than special-case it for the admin site.

It's often useful to have something like "BADDATA" assigned to TEMPLATE_STRING_IF_INVALID during development and testing, because it's easy to to scan for unforseen side effects, both visually and by a text search.

[Gary Wilson <gary.wilson@…>]

Not sure what you mean by special casing for the admin, could you please explain in more detail.

[Jeff Bauer <jbauer@…>]

Sorry, I was referring to this thread: ​http://tinyurl.com/2nxu98

A better way to phrase the issue?

Refactor the way TEMPLATE_STRING_IF_INVALID works, without special-casing it for the admin site.

[Gary Wilson <gary.wilson@…>]

Could you please point out where the special-casing exists in the admin.

[Jeff Bauer <jbauer@…>]

​http://www.djangoproject.com/documentation/templates_python/#how-invalid-variables-are-handled

"Many templates, including those in the Admin site, rely upon the silence of the template system when a non-existent variable is encountered."

[Gary Wilson <gary.wilson@…>]

Ok, this was just pointed out to me. Feel free to provide suggestions and/or patches. Marking accepted as per Adrian's comments in the mailing list post.

[Gary Wilson <gary.wilson@…>]

Here is one case where the admin relies on an empty string:
​http://groups.google.com/group/django-developers/browse_thread/thread/4af39afa4600bacc/f065cdd1ad2e6158

[buriy <burchik@…>]

First piece

[buriy <burchik@…>]

All fixes: two for action="{{ form_url }}", two for <th{{some.stuff}}>

[buriy <burchik@…>]

All fixes: two for action="{{ form_url }}", two for <th{{some.stuff}}>

[buriy <burchik@…>]

All fixes: two for action="{{ form_url }}", two for <th{{some.stuff}}>, one for <td{{some.stuff}}

[buriy <burchik@…>]

That's all. All code was looked for similar patterns.

[buriy <burchik@…>]

related but not closed tickets:

​http://code.djangoproject.com/ticket/3073 [hack for output, giving empty form_url]
​http://code.djangoproject.com/ticket/2583 [no patch, only long bug description]

[buriy <burchik@…>]

committers, anyone? week passed, no reaction.

[Malcolm Tredinnick]

Please demonstrate some patience. You may have noticed that this isn't the only ticket in Trac and it isn't the highest priority item at the moment. When we have time, it will be reviews and you'll get some feedback on what remains to be done.

[James Bennett]

#5532 was a duplicate.

[Yuri Baburov]

Added template conditionals for sometimes-non-existing variables in admin, r8445.

[Marinho Brandão]

I'm not understanding why this ticket is being considered to post-1.0 if it is (I think) the cause to bugged add-user form and others strange behaviours everytime a variable isn't valid in the template.

For example: a simple /admin/auth/user/add/ is rendering this code:

<form action="&lt;font color=&#39;red&#39;&gt;form_url&lt;/font&gt;" method="post" id="user_form">
<div>

Shouldn't this enought reason to consider this ticket?

Maybe would make it safe string or disabling this "helper" (that isn't helping nothing).

[Malcolm Tredinnick]

Making a change like this now (in feature freeze) would be destabilising, at a minimum.

Seriously, when a core maintainer triages something as post-1.0, please don't decide that you should change that. we have a mailing list if you want to ask for a reconsideration, but this isn't even borderline. It's an enhancement request that can easily be added afterwards.

[Yuri Baburov]

Replying to marinho:

For example: a simple /admin/auth/user/add/ is rendering this code:

<form action="&lt;font color=&#39;red&#39;&gt;form_url&lt;/font&gt;" method="post" id="user_form">
<div>

When TEMPLATE_STRING_IF_INVALID is empty (by default), there's no such problem.
Also it is said in the docs that

While TEMPLATE_STRING_IF_INVALID can be a useful debugging tool,
it is a bad idea to turn it on as a ‘development default’.

Many templates, including those in the Admin site, rely upon the silence
of the template system when a non-existent variable is encountered.
If you assign a value other than '' to TEMPLATE_STRING_IF_INVALID, you
will experience rendering problems with these templates and sites.

at ​http://www.djangoproject.com/documentation/templates_python/#how-invalid-variables-are-handled

Admin interface templates are relying on this behavior now in few last places. Patch for them is attached.

[Marinho Brandão]

Thank you Yuri.

Sorry, Malcolm, you both are right :)

[(none)]

Milestone post-1.0 deleted

[Luke Plant]

I think it is now too late to put this genie back in the bottle, and it isn't worth the effort trying to fix the admin or other contrib apps. Given that #3073 was marked as invalid I'm going to do the same here. Please bring to django-devs if you think it is worth the effort to fix this.