[2.0.x] Fixed #28786 -- Doc'd middleware ordering considerations due to CommonMiddleware setting Content-Length.

Backport of bc95314ca6af0b5e993ae07fdc7d8e6166d3b8ca from master

1 files changed, 3 insertions, 1 deletions

diff --git a/docs/ref/middleware.txt b/docs/ref/middleware.txt
index 5c33d196d3..9a373d076d 100644
--- a/docs/ref/middleware.txt
+++ b/docs/ref/middleware.txt
@@ -488,7 +488,9 @@ Here are some hints about the ordering of various Django middleware classes:
 
 #. :class:`~django.middleware.common.CommonMiddleware`
 
-   Before any middleware that may change the response (it calculates ``ETags``).
+   Before any middleware that may change the response (it sets the ``ETag`` and
+   ``Content-Length`` headers). A middleware that appears before
+   ``CommonMiddleware`` and changes the response must reset the headers.
 
    After ``GZipMiddleware`` so it won't calculate an ``ETag`` header on gzipped
    contents.