Hangs if a matching file is open with another instance of vim

[fvictorio]

Hi, I tried this with a fresh VM, installing just vim (7.4.52), ag (0.19.2) and ack.vim (with vim-plug).

If you open a file foo.txt with the text lorem ipsum and then, in another terminal but in the same directory, you start another vim and execute Ack lorem, the search will hang.

If you press any key, it shows this:

Error detected while processing function ack#Ack..<SNR>23_SearchWithGrep:
line    8:
E325: ATTENTION
Error detected while processing function ack#Ack:
line   41:
E171: Missing :endif

I hope that helps!