[master] 2da6c5e Document desupported VSL tags in varnishncsa

[Nils Goroll]

commit 2da6c5e539f8f858c446812d30f00de600ecc3e4
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Wed Mar 7 12:55:48 2018 +0100

    Document desupported VSL tags in varnishncsa
    
    Ref: 63807dd22725653e23c20071a9eb958642413f36
    
    Found while working on https://code.uplex.de/uplex-varnish/varnishevent

diff --git a/doc/changes.rst b/doc/changes.rst
index 4d8fb92..e7cab57 100644
--- a/doc/changes.rst
+++ b/doc/changes.rst
@@ -144,6 +144,15 @@ Logging / statistics
   bytes was attributed to the body, including any protocol overhead (ie
   chunked encoding).
 
+bundled tools
+-------------
+
+* ``varnishncsa`` refuses output formats (as defined with the ``-F``
+  command line argument) for tags which could contain control or
+  binary characters. At the time of writing, these are:
+  ``%{H2RxHdr}x``, ``%{H2RxBody}x``, ``%{H2TxHdr}x``, ``%{H2TxBody}x``,
+  ``%{Debug}x``, ``%{HttpGarbage}x`` and ``%{Hash}x``
+
 C APIs (for vmod and utility authors)
 -------------------------------------