[Varnish] #1172: Varnish sends inconsistent Vary to downstream caches

[Varnish]

#1172: Varnish sends inconsistent Vary to downstream caches
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 Reporter:  RuddO   |       Owner:
     Type:  defect  |      Status:  new
 Priority:  normal  |   Milestone:
Component:  build   |     Version:  3.0.2
 Severity:  normal  |  Resolution:
 Keywords:          |
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Comment (by RuddO):

 I have discovered this is related to the hit for pass feature.

 This is an example of a request that gets routed to miss after hash:

 /etc/varnish@… 𝛀: echo "GET /search_form HTTP/1.1 Host: declinefm.com

 " | nc localhost 80 | head -20

 HTTP/1.1 200 OK Server: Zope/(2.13.13, python 2.6.7, linux2) ZServer/1.1
 Content-Language: en Expires: Sat, 1 Jan 2000 00:00:00 GMT Vary: Accept-
 Encoding Content-Type: text/html;charset=utf-8 Transfer-Encoding: chunked
 Date: Wed, 18 Jul 2012 21:50:06 GMT X-Varnish: 13272803 Age: 0 Via: 1.1
 varnish Connection: keep-alive

 Note the Vary header there.

 Almost immediately after that, I produce another request. This, of course,
 goes straight to pass since the TTL of the previous fetch was 0 seconds,
 and so varnish registered a hit for pass for this object.

 0 <- echo "GET /search_form HTTP/1.1 Host: declinefm.com

 " | nc localhost 80 | head -20 /etc/varnish@… 𝛀: echo "GET /search_form
 HTTP/1.1 Host: declinefm.com

 " | nc localhost 80 | head -20

 HTTP/1.1 200 OK Server: Zope/(2.13.13, python 2.6.7, linux2) ZServer/1.1
 Expires: Sat, 1 Jan 2000 00:00:00 GMT Content-Type:
 text/html;charset=utf-8 Content-Language: en Transfer-Encoding: chunked
 Date: Wed, 18 Jul 2012 21:50:37 GMT X-Varnish: 13272824 Age: 0 Via: 1.1
 varnish Connection: keep-alive

 Note the absence of the Vary header here.

 I verified my backend and it has correct, consistent behavior.

 This appears to be a legitimate varnish bug.

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Ticket URL: <https://www.varnish-cache.org/trac/ticket/1172#comment:2>
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