[tmux 2.1] and TmuxSessionExists on tmuxp load pomp.yml -2

[estin]

$ tmux -V
tmux 2.1

$ tmuxp -v
tmuxp 0.9.1

$ tmux list-sessions
2: 1 windows (created Tue Oct 20 15:17:58 2015) [140x45] (attached)

$ tmux has-session -t pomp
can't find session pomp

$ cat pomp.yml | grep session_name
session_name: pomp

$ tmuxp load pomp.yml -2
load /home/user/prj/pomp.yml
(I) [15:10:01] tmuxp.cli cli.load_workspace():270 Loading /home/user/prj/pomp.yml.
Session name pomp is already running. Attach? [Y/n] Y
Traceback (most recent call last):
  File "/usr/lib/python3.5/site-packages/tmuxp/cli.py", line 271, in load_workspace
    builder.build()
  File "/usr/lib/python3.5/site-packages/tmuxp/workspacebuilder.py", line 119, in build
    self.sconf['session_name']
tmuxp.exc.TmuxSessionExists: Session name pomp is already running.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/tmuxp", line 9, in <module>
    load_entry_point('tmuxp==0.9.1', 'console_scripts', 'tmuxp')()
  File "/usr/lib/python3.5/site-packages/tmuxp/cli.py", line 968, in main
    command_load(args)
  File "/usr/lib/python3.5/site-packages/tmuxp/cli.py", line 420, in command_load
    load_workspace(file_cwd, args)
  File "/usr/lib/python3.5/site-packages/tmuxp/cli.py", line 292, in load_workspace
    builder.session.switch_client()
AttributeError: 'NoneType' object has no attribute 'switch_client'

Sever.has_session does not check output can't find session

[robled]

I've tested your patch and can confirm that it works with my installation of tmux 2.1.

[DXist]

I reproduce this issue when I answer 'yes' to '... is already running. Attach? [Y/n]:'

Traceback

Traceback (most recent call last):
  File "/usr/local/bin/tmuxp", line 11, in <module>
    sys.exit(cli.cli())
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 716, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 696, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 1060, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 889, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 534, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/tmuxp/cli.py", line 484, in command_load
    load_workspace(config[-1], **tmux_options)
  File "/usr/local/lib/python2.7/dist-packages/tmuxp/cli.py", line 253, in load_workspace
    reattach(builder.session)
  File "/usr/local/lib/python2.7/dist-packages/tmuxp/cli.py", line 241, in reattach
    session.switch_client()
AttributeError: 'NoneType' object has no attribute 'switch_client'

tmux version is 2.1
tmuxp version is 1.2.0

[DXist]

Sounds like the reason #132