Better support for __html__ in django admin

[Olivier Dalang]

Django supports custom html representation for objects using the html method (see https://code.djangoproject.com/ticket/7261)

This is supposedly used when trying to display to object as html : if the object provides an html representation, this is used instead of an html-escaped version of str. This is implemented in django.utils.html.conditional_escape, used in turn by format_html (and similar).

This feature is really nice. It allows for instance to add colors or icons to the instances representation very consistently., which in some cases can really help in terms of UX (e.g. color for instance's state).

Unfortunately, this is is only very partially supported in Django admin, where most of the time, the str representation is used instead.

Currently, the only place where I could see the html used is in the confirmation message after changing an object ("The object “XYZ” was changed successfully.).

The html method is not used in :

• the default representation of the changelist (when list_display is not set)
• the breadcrumbs
• the filters of the changelist
• the select with autocomplete (despite select2 supporting html)
• etc...

I suggest changing this wherever possible in Django admin. It shouldn't be too big of a change. It's probably mostly replacing str(obj) by conditional_escape(obj) wherever HTML is admissible.

Long live Django & Django admin :-)