NotImplementedError: "should resend request to, but this isn't implemented" during lp name lookup

Bug #558343 reported by Lorenzo Marcantonio on 2010-04-08
This bug affects 34 people
Affects Status Importance Assigned to Milestone
Robert Collins
Andrew Bennetts
Launchpad itself
bzr (Ubuntu)

Bug Description

Just installed python-2.6.5, pycrypto, paramiko and bzr-2.1.0. All the preliminary tests described into the bzr install pages succeeded.

When doing a bzr branch lp:kicad it fails with this trace:

bzr: ERROR: exceptions.NotImplementedError: should resend request to, but this isn't implemented

Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 853, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 1055, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 661, in run_argv_aliases
    return self.run_direct(**all_cmd_args)
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 665, in run_direct
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 122, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 156, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 1194, in run
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 958, in open_tree_or_branch
    bzrdir =
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 842, in open
    t = get_transport(base, possible_transports=possible_transports)
  File "/usr/lib/python2.6/site-packages/bzrlib/", line 125, in __call__
    return obj(*args, **kwargs)
  File "/usr/lib/python2.6/site-packages/bzrlib/transport/", line 1555, in get_transport
    base = directories.dereference(base)
   File "/usr/lib/python2.6/site-packages/bzrlib/", line 58, in dereference
    return service().look_up(name, url)
  File "/usr/lib/python2.6/site-packages/bzrlib/plugins/launchpad/", line 60, in look_up
    return self._resolve(url)
  File "/usr/lib/python2.6/site-packages/bzrlib/plugins/launchpad/", line 70, in _resolve
    result = resolve.submit(service)
  File "/usr/lib/python2.6/site-packages/bzrlib/plugins/launchpad/", line 275, in submit
  File "/usr/lib/python2.6/site-packages/bzrlib/plugins/launchpad/", line 205, in send_request
    % e.headers.get('Location', 'NO-LOCATION-PRESENT'))
NotImplementedError: should resend request to, but this isn't implemented

bzr 2.1.0 on python 2.6.5 (Linux-
arguments: ['/usr/bin/bzr', 'branch', 'lp:kicad']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'it_IT.utf8'
  launchpad /usr/lib/python2.6/site-packages/bzrlib/plugins/launchpad [2.1.0]
  netrc_credential_store /usr/lib/python2.6/site-packages/bzrlib/plugins/netrc_credential_store [2.1.0]
  news_merge /usr/lib/python2.6/site-packages/bzrlib/plugins/news_merge [2.1.0]

*** Bazaar has encountered an internal error. This probably indicates a
    bug in Bazaar. You can help us fix it by filing a bug report at
    including this traceback and a description of the problem.

Any ideas about what's happening?

Related branches

Tried without proxy, it works... I think it's a duplicate of #186920

Andrew Bennetts (spiv) wrote :

This apparently happens when the XML-RPC request from the lp plugin gets a 301 response, presumably the Location header in that response should be tried.

Changed in bzr:
importance: Undecided → Medium
status: New → Confirmed
tags: added: launchpad lp-login

Does Launchpad really want us to get bzr stuff from It seems like a server side error.

Lorenzo, if you can reproduce this, can you please try again with the
-Dhttp option and attach the log file from that.

It seem so, it's perfectly reproducible when http_proxy/https_proxy is set. I'll attach the log

Martin Pool (mbp) wrote :

Thanks, that helps a lot; it's interesting that someone else hit this recently.

I see you have a proxy at, and we're trying to CONNECT through it, which is ok. But this request looks wrong to me:

0.829 > POST /bazaar/
0.829 > Content-Length: 164
> Connection: Keep-Alive
> Accept: */*
> User-Agent: bzr/2.1.0 (urllib)
> Host:
> Pragma: no-cache
> Cache-Control: max-age=0
> Content-Type: text/xml

Surely the 'Host' header should be, not that of the proxy?

I think Launchpad is then being a bit weird by sending a redirect to a nonexistent feeds url rather than just giving an error that there is no host Probably feeds.l.n is the default vhost. That should be fixed too.

tags: added: http
summary: - NotImplementedError: should resend request to
-, but this isn't implemented
+ NotImplementedError: "should resend request to
+, but this isn't implemented"
+ during lp name lookup
Curtis Hovey (sinzui) on 2010-04-14
affects: launchpad → launchpad-foundations
Gary Poster (gary) wrote :

I agree with Martin that the Host header looks broken.

If the only problem on the Launchpad side is the weirdness he describes, I'm triaging this as low on our side. I'll keep an eye on this to see if there is a diagnosis that points to something more serious.

I did do a quick once-over to see if I could find the pertinent code path in Launchpad that would cause this behavior. I didn't see anything obvious. An AssertionError or a KeyError seem to by the likely thing to happen on the Launchpad side with an XMLRPC request pointing to an unknown host.

Changed in launchpad-foundations:
status: New → Triaged
importance: Undecided → Low
Martin Pool (mbp) wrote :

So the fix on the Bazaar side is probably that we should make sure xmlrpclib (or whatever) puts in the correct destination Host when it's using a proxy.

a.cavallo (a.cavallo) wrote :

Why this has been moved to low importance: to me it looks a showstopper.

Robert Collins (lifeless) wrote :

bumping to high in bazaar - duplicates are starting to accrue

Changed in bzr:
importance: Medium → High
Robert Collins (lifeless) wrote :

def request(self, host, handler, request_body, verbose=0) in the lp registration module recieves '' as the host.

Robert Collins (lifeless) wrote :

To reproduce:
apt-get install squid3
http_proxy= https_proxy= /usr/bin/bzr info lp:epics-base/3-14

Robert Collins (lifeless) wrote :

We do the following:
CONNECT to tunnel through the proxy
SSL after that, so wireshark isn't all that helpful.

In the failing method I see:
(Pdb) print proxy._ServerProxy__host
(Pdb) proxy._ServerProxy__transport._opener
<bzrlib.transport.http._urllib2_wrappers.Opener object at 0x1e781d0>

Deep in urllib2, in do_request, line 1080, request.has_proxy is False - this is interesting and seems to be due to the urllib2 set_proxy methods behaviour. I'll need to stare harder at this to understand it I think.

and online 1084 is where the wrong Host header is set.

Now, Its my first time looking at this code, but I think the simplest thing up front is to set Host ourselves. The backtrace is:
-> response =
-> req = meth(req)
> /usr/lib/python2.6/
-> if not request.has_header('Host'):

More later, a quick attempt at that hasn't worked.

Robert Collins (lifeless) wrote :

Ok, found an incantation that appears to work for me. Feedback solicited!

Martin Pool (mbp) on 2010-05-08
Changed in bzr:
status: Confirmed → In Progress
Changed in bzr:
status: In Progress → Fix Released
assignee: nobody → Robert Collins (lifeless)
milestone: none → 2.2b3
Martin Pool (mbp) wrote :

Could/should we backport this to 2.1 or 2.0?

Paul Gear (paulgear) wrote :

When will this be available in lucid updates? It makes bzr unusable on my system.

Andrew Bennetts (spiv) wrote :

Paul: that's a good question. The fix hasn't been backported to the 2.1 branch, but as comment #17 says it's probably a good candidate for backporting. After that we'd need to kick off the SRU process (possibly making a 2.1.4 release would ease that)... So I'd guess it'd be weeks away at least.

In the meantime you may find the bzr PPA to be helpful, it has 2.2.0 for lucid, which includes this fix: <>

Martin Pool (mbp) wrote :

@Paul, as a workaround you can also use bzr+ssh urls, eg bzr+ssh://

Bug description:
root@ubuntu2:/opt/openstack# bzr branch lp:nova
bzr: ERROR: exceptions.NotImplementedError: should resend request to, but this isn't implemented

*** Bazaar has encountered an internal error. This probably indicates a
    bug in Bazaar. You can help us fix it by filing a bug report at
    attaching the crash file
    and including a description of the problem.

    The crash file is plain text and you can inspect or edit it to remove
    private information.

Vincent Ladeuil (vila) wrote :

@Lakshmi: You need to upgrade your bzr version to get the fix that's why I marked your report as a duplicate of this one.
This isn't related to your branch so there is no need to add more comments here unless you're using an upgraded bzr and still encounter the problem.

'bzr version' will tell you which version you are currently using (2.1.1 from your crash report)

See coment #19 above too.

Jelmer Vernooij (jelmer) on 2011-03-16
Changed in bzr (Ubuntu):
status: New → Fix Released

Accepted bzr into maverick-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See for documentation how to enable and use -proposed. Thank you in advance!

Changed in bzr (Ubuntu Maverick):
status: New → Fix Committed
tags: added: verification-needed
Martin Pool (mbp) wrote :

verification done:

I set up a squid proxy per Robert's comment #13, and ran

http_proxy= https_proxy= /usr/bin/bzr info lp:epics-base

using maverick's original 2.2.0-1. It worked. This bug was actually fixed prior to the bzr release shipped in maverick, and so is not especially relevant to the maverick SRU. It still works in 2.2.4-0ubuntu1.

It would, however, be good to do a separate lucid sru to get this fix from bzr 2.1.4.

Changed in bzr (Ubuntu Maverick):
status: Fix Committed → Fix Released
Martin Pool (mbp) on 2011-04-21
tags: added: verification-done
removed: verification-needed
Clint Byrum (clint-fewbar) wrote :

Accepted bzr into lucid-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See for documentation how to enable and use -proposed. Thank you in advance!

Changed in bzr (Ubuntu Lucid):
status: New → Fix Committed
tags: removed: verification-done
tags: added: verification-needed
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package bzr - 2.1.4-0ubuntu1

bzr (2.1.4-0ubuntu1) lucid-proposed; urgency=low

  * Update watch file to use 2.1 series.
  * New upstream release.
   + Fix file descriptors leaks in dirstate compiled extension. LP: #583486
   + Refuse to stack on repositories in incompatible formats. LP: #562380
   + Don't delete nested trees/repos. LP: #572098
   + Fix 'bzr switch' crash when a 'ConfigurableFileMerger' is used. LP: #559436
   + Fix compatibility with older smart servers. LP: #528041
   + Fix symlinks addition. LP: #192859
   + Properly unversion children of unversioned directories. LP: #494221
   + Lock configuration files in '~/.bazaar' for updates. LP: #525571
   + Fix 'bzr commit <symlink>'. LP: #128562
   + Fix `lp:` urls when behind an http proxy. LP: #558343
   + Stop using LP: #583667
 -- Max Bowsher <email address hidden> Tue, 17 May 2011 09:54:17 +0100

Changed in bzr (Ubuntu Lucid):
status: Fix Committed → Fix Released
sphen (faulkzz) on 2016-10-16
Changed in launchpad:
assignee: nobody → sphen (faulkzz)
status: Triaged → Incomplete
status: Incomplete → Confirmed
status: Confirmed → Opinion
Colin Watson (cjwatson) on 2016-10-16
Changed in launchpad:
status: Opinion → Triaged
assignee: sphen (faulkzz) → nobody
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