[Varnish] #1688: ESI-included synthetic response is delivered uncompressed within a gzipped response

[Varnish]

#1688: ESI-included synthetic response is delivered uncompressed within a gzipped
response
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 Reporter:  geoff                       |       Type:  defect
   Status:  new                         |   Priority:  normal
Milestone:  Varnish 4.0 release         |  Component:  varnishd
  Version:  4.0.3                       |   Severity:  major
 Keywords:  esi include synthetic gzip  |
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 In Varnish 4 (apparently in every release version <= 4.0.3), a synthetic
 response that is ESI-included within a gzipped response appears
 uncompressed in the midst of the gzip stream. gunzip fails, so the client
 response is unreadable.

 I'll be attaching a VTC test that demonstrates the problem, and the log of
 a varnishtest run.

 The conditions are that the response is synthetic and ESI-included, and
 Accept-Encoding:gzip appears in the request for the including response.
 The test log shows that there is no error when gzip-Encoding is not
 requested. When the response is gzipped, you can see that the uncompressed
 ESI response appears as a chunk in between gzipped chunks.

 I've tried the test with each of the 4.0.0 through 4.0.3 releases (by
 checking out the tags and building from the source repo), and it failed in
 all of them.

-- 
Ticket URL: <https://www.varnish-cache.org/trac/ticket/1688>
Varnish <https://varnish-cache.org/>
The Varnish HTTP Accelerator