Contradictory advice on middleware order

[david@…]

From ​https://docs.djangoproject.com/en/dev/ref/middleware/#django.middleware.gzip.GZipMiddleware

It is suggested to place this first in the middleware list, so that the compression
of the response content is the last thing that happens.

From ​https://docs.djangoproject.com/en/dev/topics/cache/#order-of-middleware-classes

you need to make sure that UpdateCacheMiddleware appears before any other middleware
that might add something to the Vary header. The following middleware modules do so:

SessionMiddleware adds Cookie
GZipMiddleware adds Accept-Encoding

I suspect ​https://docs.djangoproject.com/en/dev/ref/middleware/#django.middleware.gzip.GZipMiddleware might need to be changed. With GZipMiddleware first, not only will it alter the "Vary" header handling, but presumably it will be recompressing the uncompressed cached content on each request, and it would be better to cache the compressed content instead.

[Luke Plant]

The gzip docs should say something like it should run after anything else that needs to read/write the response body.

[Tim Graham <timograham@…>]

In 3e0857041b6bfc9deef392315c978abede706c92:

Fixed #18473 - Fixed a suggestion that GZipMiddleware needs to be first in the list of middleware.

[Tim Graham <timograham@…>]

In 73991b0b325f07fc62179c3684ed921f141e69ce:

[1.4.X] Fixed #18473 - Fixed a suggestion that GZipMiddleware needs to be first in the list of middleware.

Backport of 3e0857041b from master