Un-pickled TemplateResponse objects can't be re-pickled

[Niran Babalola]

Pickling a TemplateResponse removes attributes that deal with rendering, presumably to make it clear that un-pickled TemplateResponses are completely baked and you can't do the typical things you'd do with a normal TemplateResponse. However, there's no check that ensures that the attributes exist before removing them, so if you try to re-pickle a TemplateResponse, you get a KeyError.

[Niran Babalola]

I've attached a patch that fixes the problem. A further improvement would be for an un-pickled TemplateResponse to raise a more explicit exception when the removed attributes are accessed so it's clear what is going on.

[Aymeric Augustin]

Since TemplateResponse contains code to deal with pickling, it's reasonable to expect pickling - unpickling - pickling to work.

I think the rationale for stripping these attributes is to avoid storing a large amount of computed data. I'd expect them to be regenerated during unpickling, or on demand when the response is rendered; I haven't checked the details.

[Niran Babalola]

Added a new patch that raises the exception I described earlier and tests everything.

[Łukasz Rekucki]

The patch and tests look good. Only missing thing is {{{from future import with_statement}} for Python 2.5 (attaching fixed patch).

[Jannis Leidel]

In [16568]:

Fixed #16326 -- Fixed re-pickling of unpickled TemplateResponse instances. Thanks, natrius and lrekucki.