[Crossbow] Unintuitive error message when remote branch has not been pushed

[asfimport]

$ python dev/tasks/crossbow.py submit -g linux --arrow-version 0.11.1-rc0
Traceback (most recent call last):
  File "dev/tasks/crossbow.py", line 796, in <module>
    crossbow(obj={}, auto_envvar_prefix='CROSSBOW')
  File "/home/wesm/miniconda/envs/arrow-release/lib/python3.6/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/home/wesm/miniconda/envs/arrow-release/lib/python3.6/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/home/wesm/miniconda/envs/arrow-release/lib/python3.6/site-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/wesm/miniconda/envs/arrow-release/lib/python3.6/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/wesm/miniconda/envs/arrow-release/lib/python3.6/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/home/wesm/miniconda/envs/arrow-release/lib/python3.6/site-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "dev/tasks/crossbow.py", line 596, in submit
    target = Target.from_repo(arrow)
  File "dev/tasks/crossbow.py", line 407, in from_repo
    remote=repo.remote_url,
  File "dev/tasks/crossbow.py", line 235, in remote_url
    return self.remote.url.replace(
  File "dev/tasks/crossbow.py", line 225, in remote
    return self.repo.remotes[self.branch.upstream.remote_name]
AttributeError: 'NoneType' object has no attribute 'remote_name'

The fix was to make sure the local branch and the reference branch for the build in my fork wesm/arrow was the same

Reporter: Wes McKinney / @wesm
Assignee: Krisztian Szucs / @kszucs

_{Note: This issue was originally created as ARROW-3579. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
@kszucs can you take a look at this?

[asfimport]

Krisztian Szucs / @kszucs:
It is already resolved: https://github.com/apache/arrow/blob/master/dev/tasks/crossbow.py#L560-L564