mod_rewrite/6213: Vary header issues (pr 1644) not documented

[Gregory Stark <gs...@Mit.edu>]

>Number:         6213
>Category:       mod_rewrite
>Synopsis:       Vary header issues (pr 1644) not documented
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    apache
>State:          open
>Class:          doc-bug
>Submitter-Id:   apache
>Arrival-Date:   Mon Jun 19 14:40:02 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator:     gsstark@Mit.edu
>Release:        1.3.12
>Organization:
apache
>Environment:
Apache 1.3.12 with mod_rewrite
>Description:
The issues discussed in pr 1644 were addressed in the source code however the changes
made (magically setting the Vary header) were never documented in the mod_rewrite
documentation. Until those changes are documented pr 1644 should not be considered
completely resolved. Ideally the original pr should have been left open.

In any case without implementing the ability to override the new behaviour means
there's no a major undocumented gotcha in 1.3.12 that isn't mentioned in upgrading
notes or even in the mod_rewrite documentation. A user upgrading will suddenly
start sending Vary headers and have no reference on why and no way to disable them.
>How-To-Repeat:
Upgrade a server using mod_rewrite to 1.3.12 and watch clients suddenly start to
fail to cache. Scratch your head as to why.

>Fix:
Besides documentation, the only work-around currently is to add
E=force-no-vary:t to your mod_rewrite rules. This is far from ideal as it 
completely disables the Vary header rather than merely leaving it unmodified.

The NV flag suggested in pr 1644 would be a preferable solution.
>Release-Note:
>Audit-Trail:
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