Tarmac crashes if approved revision is overwritten

[Zygmunt Krynicki]

To reproduce:

1) Push a branch, say at revno 10
2) Create a merge request and approve it
3) Push --overwrite the same branch with the last revision changed (uncommit + change + commit) or rebase
4) Ask tarmac to merge this

Preparing to merge lp:~zkrynicki/checkbox/checkbox-provider-refactor
An error occurred trying to merge lp:checkbox: Server sent an unexpected error: ('error', 'GhostRevisionsHaveNoRevno', 'Could not determine revno for {<email address hidden>} because its ancestry shows a ghost at {tarmac-20130312094654-46gzbaa0xtfyv03d}')
Traceback (most recent call last):
  File "./bin/tarmac", line 6, in <module>
    main()
  File "/home/zyga/tarmac/tarmac/bin/__init__.py", line 30, in main
    registry.run(args)
  File "/home/zyga/tarmac/tarmac/bin/registry.py", line 60, in run
    self._run(args)
  File "/home/zyga/tarmac/tarmac/bin/registry.py", line 48, in _run
    run_bzr(args)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 1121, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 673, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 697, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/home/zyga/tarmac/tarmac/bin/commands.py", line 370, in run
    self._do_merges(branch)
  File "/home/zyga/tarmac/tarmac/bin/commands.py", line 212, in _do_merges
    str(proposal.reviewed_revid))
  File "<string>", line 4, in revision_id_to_revno_read_locked
  File "/usr/lib/python2.7/dist-packages/bzrlib/remote.py", line 3885, in revision_id_to_revno
    self._remote_path(), revision_id)
  File "/usr/lib/python2.7/dist-packages/bzrlib/remote.py", line 75, in _call
    self._translate_error(err, **err_context)
  File "/usr/lib/python2.7/dist-packages/bzrlib/remote.py", line 3454, in _translate_error
    self.repository._translate_error(err, branch=self, **context)
  File "/usr/lib/python2.7/dist-packages/bzrlib/remote.py", line 1347, in _translate_error
    self.bzrdir._translate_error(err, repository=self, **context)
  File "/usr/lib/python2.7/dist-packages/bzrlib/remote.py", line 491, in _translate_error
    _translate_error(err, bzrdir=self, **context)
  File "/usr/lib/python2.7/dist-packages/bzrlib/remote.py", line 4194, in _translate_error
    raise errors.UnknownErrorFromSmartServer(err)
bzrlib.errors.UnknownErrorFromSmartServer: Server sent an unexpected error: ('error', 'GhostRevisionsHaveNoRevno', 'Could not determine revno for {<email address hidden>} because its ancestry shows a ghost at {tarmac-20130312094654-46gzbaa0xtfyv03d}')

[dobey (dobey)]

I'm not sure what that error means exactly, or what the expected behavior from tarmac would be when it encounters this error, or other unknown errors from the server. Can you clarify (or ask a bzr/launchpad developer to clarify what the error means)?

[John A Meinel (jameinel)]

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On 2013-03-13 22:11, Rodney Dawes wrote:
> I'm not sure what that error means exactly, or what the expected
> behavior from tarmac would be when it encounters this error, or
> other unknown errors from the server. Can you clarify (or ask a
> bzr/launchpad developer to clarify what the error means)?
>

It should say that it cannot merge the request on the original Merge
Proposal and reject the change. It should not be crashing inside tarmac.

John
=:->
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