You can clone with
HTTPS or Subversion.
How to reproduce:
I've configured my Emacs to use pr. project history files by creating the following file:
with the content:
((nrepl-history-size . 100)
(nrepl-history-file . "~/Projects/my-project/.nrepl-hist.eld"))))
Now open a file from the my-project directory (or any subdirectory) so the above file is loaded.
The do a "nrepl-jack-in"
Followed by a "nrepl-quit"
Now try to Quit: C-x C-c
I get the error: "nrepl-history-read: Wrong type argument: stringp, nil"
and Emacs stays open. If I do a "nrepl-jack-in" again a tries to close while the nrepl is running it is possible to close Emacs.
Emacs: emacs.x86_64 24.3-11.fc19
I could not reproduce your problem.