rbenv and "(wrong-type-argument stringp nil)" error

[wdenton]

I just switched over to rbenv and something is stopping M-x inf-ruby from starting the REPL. It must be something with my configuration, but I can't see what.

My Ruby setup in Emacs is here and as far as I can tell rbenv is set up pretty normally:

https://github.com/wdenton/.emacs.d/blob/master/setup/setup-ruby.el

(getenv "PATH") shows rbenv the way it should.

When I run M-x inf-ruby (with debugging on) I get this, but I can't figure out where the problem is.

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  expand-file-name(nil)
  inf-ruby-buffer()
  run-ruby("irb --prompt default --noreadline -r irb/completion" "ruby")
  inf-ruby("ruby")
  funcall-interactively(inf-ruby "ruby")
  #<subr call-interactively>(inf-ruby record nil)
  ad-Advice-call-interactively(#<subr call-interactively> inf-ruby record nil)
  apply(ad-Advice-call-interactively #<subr call-interactively> (inf-ruby record nil))
  call-interactively(inf-ruby record nil)
  command-execute(inf-ruby record)
  execute-extended-command(nil "inf-ruby")
  smex-read-and-run(("inf-ruby" "inf-ruby-console-auto" "R" "S" "cd" "5x5" "arp" "S+" "S+3" "S+6" "SAS" "dbx" "dig" "erc" "ert" "eww" "ftp" "gdb" "irc" "jdb" "man" "mpc" "pdb" "pwd" "rsh" "sdb" "xdb" "calc" "diff" "dirs" "ffap" "gnus" "grep" "help" "ielm" "info" "life" "mail" "mpuz" "ping" "pong" "smex" "talk" "term" "undo" "yank" "zone" "align" "chmod" "debug" ...))
  smex()
  funcall-interactively(smex)
  #<subr call-interactively>(smex nil nil)
  ad-Advice-call-interactively(#<subr call-interactively> smex nil nil)
  apply(ad-Advice-call-interactively #<subr call-interactively> (smex nil nil))
  call-interactively(smex nil nil)
  command-execute(smex)

[wdenton]

In case this is the same as #96, I'm running 20161129.702 from MELPA.

[dgutov]

Exactly the same, yes, and it's a bug on our side, sorry.

Thanks for reporting anyway.