empty account listing inconsistent 204/200 reply with format=json

BEFORE (fd3acd2e5944251b3a473d2936f33f11101d56e4^1):

    clayg@swift:~$ curl -H 'x-auth-token: AUTH_tk' http://localhost/v1/AUTH_test?format=json -v
    * About to connect() to localhost port 80 (#0)
    * Trying 127.0.0.1... connected
    > GET /v1/AUTH_test?format=json HTTP/1.1
    > User-Agent: curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0 OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3
    > Host: localhost
    > Accept: */*
    > x-auth-token: AUTH_tk1652a904f71a4869a13df050e6e886e2
    >
    < HTTP/1.1 200 OK
    < Content-Length: 2
    < Accept-Ranges: bytes
    < X-Timestamp: 1369274744.48164
    < X-Account-Bytes-Used: 0
    < X-Account-Container-Count: 0
    < Content-Type: application/json; charset=utf-8
    < X-Account-Object-Count: 0
    < Date: Thu, 23 May 2013 02:05:50 GMT
    <
    * Connection #0 to host localhost left intact
    * Closing connection #0
    []

AFTER (master):

    clayg@swift:~$ curl -H 'x-auth-token: AUTH_tk' http://localhost/v1/AUTH_test?format=json -v
    * About to connect() to localhost port 80 (#0)
    * Trying 127.0.0.1... connected
    > GET /v1/AUTH_test?format=json HTTP/1.1
    > User-Agent: curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0 OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3
    > Host: localhost
    > Accept: */*
    > x-auth-token: AUTH_tk1652a904f71a4869a13df050e6e886e2
    >
    < HTTP/1.1 204 No Content
    < Content-Length: 0
    < Accept-Ranges: bytes
    < X-Timestamp: 1369274645.16959
    < X-Account-Bytes-Used: 0
    < X-Account-Container-Count: 0
    < Content-Type: text/plain; charset=utf-8
    < X-Account-Object-Count: 0
    < Date: Thu, 23 May 2013 02:04:05 GMT
    <
    * Connection #0 to host localhost left intact
    * Closing connection #0

Yeah, I agree the response change isn't right. The xml response changed too, of course. I'm actually surprised my Swiftly handled this okay; I must've had a similar situation somewhere else in Swift before.

Anyway, this should be fixed before the next "official" release, so I'm going to up the levels or whatever. Maybe Hadas would like to tackle this since he was just in there?

Fix proposed to branch: master
Review: https://review.openstack.org/30797

Reviewed: https://review.openstack.org/30797
Committed: http://github.com/openstack/swift/commit/15c2ca55f02e1785f999a6790d9a5ff033449bcb
Submitter: Jenkins
Branch: master

commit 15c2ca55f02e1785f999a6790d9a5ff033449bcb
Author: Samuel Merritt <email address hidden>
Date: Thu May 23 18:53:51 2013 -0700

    Fix faked-out account GET for JSON and XML.

    If account autocreation is on and the proxy receives a GET request for
    a nonexistent account, it'll fake up a response that makes it look as
    if the account exists, but without reifying that account into sqlite
    DB files.

    That faked-out response was just fine as long as you wanted a
    text/plain response, but it didn't handle the case of format=json or
    format=xml; in those cases, the response would still be
    text/plain. This can break clients, and certainly causes crashes in
    swift3. Now, those responses match as closely as possible.

    The code for generating an account-listing response has been pulled
    into (the new) swift.account.utils module, and both the fake response
    and the real response use it, thus ensuring that they can't
    accidentally diverge. There's also a new probe test for that
    non-divergence.

    Also, cleaned up a redundant matching of the Accept header in the code
    for generating the account listing.

    Note that some of the added tests here pass with or without this code
    change; they were added because the code I was changing (parts of the
    real account GET) wasn't covered by tests.

    Bug 1183169

    Change-Id: I2a3b8e5d9053e4d0280a320f31efa7c90c94bb06