{"action":"opened","issue":{"url":"https://api.github.com/repos/vim-airline/vim-airline/issues/1171","repository_url":"https://api.github.com/repos/vim-airline/vim-airline","labels_url":"https://api.github.com/repos/vim-airline/vim-airline/issues/1171/labels{/name}","comments_url":"https://api.github.com/repos/vim-airline/vim-airline/issues/1171/comments","events_url":"https://api.github.com/repos/vim-airline/vim-airline/issues/1171/events","html_url":"https://github.com/vim-airline/vim-airline/issues/1171","id":154880930,"number":1171,"title":"` variable: b:airline_head` - possibly interaction with fzf-vim+tmux","user":{"login":"ashb","id":34150,"avatar_url":"https://avatars.githubusercontent.com/u/34150?v=3","gravatar_id":"","url":"https://api.github.com/users/ashb","html_url":"https://github.com/ashb","followers_url":"https://api.github.com/users/ashb/followers","following_url":"https://api.github.com/users/ashb/following{/other_user}","gists_url":"https://api.github.com/users/ashb/gists{/gist_id}","starred_url":"https://api.github.com/users/ashb/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ashb/subscriptions","organizations_url":"https://api.github.com/users/ashb/orgs","repos_url":"https://api.github.com/users/ashb/repos","events_url":"https://api.github.com/users/ashb/events{/privacy}","received_events_url":"https://api.github.com/users/ashb/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2016-05-14T23:27:48Z","updated_at":"2016-05-14T23:27:48Z","closed_at":null,"body":"Sometimes (but only about 10% of the time) when I use the running `:FzfBuffers<CR>` (from the FZF.vim https://github.com/junegunn/fzf.vim repo)  to switch back to and older buffer I get an error :( :\r\n\r\n```\r\nError detected while processing function fzf#vim#buffers..<SNR>106_fzf..fzf#run..<SNR>81_execute_tmux..airline#extensions#branch#get_head..airline#extensions#branch#head:\r\nline   36:\r\nE121: Undefined variable: b:airline_head\r\nE116: Invalid arguments for function empty(b:airline_head)\r\nE15: Invalid expression: !empty(b:airline_head)\r\n```\r\n\r\nThe annoying this is that this happens regularly but not with in a way I've managed to track down the behaviour yet. My dot files aren't publicly available and untill I can reliably reproduce this is mostly just a \"Has anyone else seen it?\" or \"How can I add some debugging to find out what is actually going on here?\"\r\n\r\n#### environment\r\n\r\n- vim: Vi IMproved 7.4 Included patches: 1-8743\r\n- vim-airline: 30f078daf569e7d5e4f7829e39316387af349b41 (git submodule at this revision)\r\n- fzf.vim: 852cfa0c11d5661d79ed1faf1cc211b3c6ef7b00\r\n- OS: OS X\r\n terminal: iTerm2 + tmux 2.1\r\n- $TERM variable: screen-256color\r\n- color configuration (:set t_Co?): 256\r\n"}}