Bug#42363: apt: http method through caching proxy fails

[<dolittle@weniac.math.toronto.edu>]

Package: apt
Version: 0.3.11
Severity: normal

I am upgrading several machines using dpkg/apt with http.  I set up one
with apache-ssl to act as a caching proxy with the following additions
to the httpd.conf file:

# ----------------------------Proxy--------------------------------
ProxyRequests on
CacheRoot /var/cache/apache-ssl-proxy
# 100 MB = 100000 kB
CacheSize 100000
CacheGcInterval 1
# 168 hours = 7 days
CacheMaxExpire 168
# ----------------------------Proxy--------------------------------

I set up apt on all the machines to send http requests through the
proxy with the following apt.conf file:

# -------------------apt.conf------------------
Acquire {

  http {
    Proxy "http://192.168.68.1:80/";;
  };

};
# -------------------apt.conf------------------

Now, whenever apt makes a request for a package which has been cached,
I get the message (seemingly at the very beginning of the transfer or
after a few 100 bytes have been sent):

	E: size mismatch for package whatever

I then have to restart the transfer manually, even if I set Retries to
"2". The second and subsequent requests for a cached package seem to go
fine.

I suspect this is due to lack of support in apt of a certain aspect of
the http/proxy protocol, which is why I am reporting this as an apt
bug, but that is just a guess.

-- System Information
Debian Release: potato
Kernel Version: Linux yomama 2.0.35 #1 Sun Dec 27 22:51:43 EST 1998 i586 unknown

Versions of the packages apt depends on:
ii  libc6           2.1.2-0pre2    GNU C Library: Shared libraries and timezone
ii  libstdc++2.9-gl 2.91.66-2      The GNU stdc++ library (EGCS version)