Bugs when powerline is loaded earlier

[Silex]

Hello,

This bug is kinda weird, so I'm not sure if it really belongs here or in powerline. I also don't suffer from it because right now back-button is loaded before powerline so everything works fine, which makes me lazy enough to simply report instead of finding the cause :P

If you want to see it tho, here is how to reproduce:

• Use MELPA
• M-x package-install back-button
• M-x package-install powerline
• M-x powerline-default-theme
• M-x back-button-mode

This yields the following backtrace:

Debugger entered--Lisp error: (wrong-type-argument consp nil)
  byte-code("\303>\206 \304>\305    \235\204\n    \nAB\241\210*\303\207" [mode-line-format newcdr cell mode-line-position mode-line-buffer-identification smartrep-mode-line-string] 3)
  require(smartrep nil t)
  byte-code("\300\301!\210\300\302\303\304#\210\300\305\303\304#\210\300\306\303\304#\210\300\307\303\304#\210\310\311\303\312\313\314\315\316\315\317\315\320\321\322\323\324\323\325&\210\326\327\330\331\332\333\323\311&\210\334\327\335\304#\210\326\336\303\337\332\340\323\311&\210\326\341\304\342\332\340\323\311&\210\326\343\304\344\332\340\323\311&\210\326\345\303\346\332\340\323\311&\210\326\347\303\350\332\340\323\311&\210\310\351\303\352\323\311%\210\326\353\354\355\332\356\323\351&\210\326\357\360\361\332\362\323\351&\210\326\363\364\365\332\333\323\351&\210\326\366\367\370\332\333\323\351&\210\310\371\303\372\323\311%\210\326\373\374\375\332\333\323\371&\210\326\376\377\201@\332\201A\323\371&\210\326\201B\201C\201D\332\201E\323\371&\210\326\201F\201G\201H\332\201I\323\371&\210\326\201J\201K\201L\332\201M\323\371&\210\326\201N\201O\201P\332\201Q\323\371&\210\326\201R\201S\201T\332\201U\323\371&\207" [require cl smartrep nil t nav-flash visible-mark ucs-utils custom-declare-group back-button "Visual navigation through mark rings." :version "0.6.6" :link (emacs-commentary-link :tag "Commentary" "back-button") (url-link :tag "GitHub" "http://github.com/rolandwalker/back-button") (url-link :tag "EmacsWiki" "http://emacswiki.org/emacs/BackButton") :prefix "back-button-" :group convenience navigation custom-declare-variable back-button-mode-lighter " back" "This string appears in the mode-line when `back-button-mode' is active.\n\nSet to nil or the empty string to disable the mode-line\nlighter for `back-button-mode'." :type string put risky-local-variable back-button-less-feedback "Give less echo area feedback." boolean back-button-show-toolbar-buttons "Add buttons to the toolbar." back-button-show-visible-marks "Temporarily show marks using `visible-mark' when available." back-button-no-wrap "Do not wrap around the ring when navigating marks." back-button-never-push-mark "Never add a mark while navigating marks.\n\nThis option makes the back-button command work more like the\nstandard `pop-global-mark command', but breaks the functionality\nof remembering the start location." back-button-index "How to display the mark-ring index after interactive commands." back-button-show-index (quote echo) "How to display the mark-ring index.\n\nThis indicator shows progress through the ring after each\ncommand." (choice (const :tag "Echo Area" echo) (const :tag "Popup" popup) (const :tag "None" nil)) back-button-index-timeout 2 "How long to display the mark-ring index after each command.\n\nSet to nil or 0 for no timeout." ...] 18)
  autoload-do-load((autoload "back-button" "Turn on back-button-mode.\n\nWhen called interactively with no prefix argument this command\ntoggles the mode.  With a prefix argument, it enables the mode\nif the argument is positive and otherwise disables the mode.\n\nWhen called from Lisp, this command enables the mode if the\nargument is omitted or nil, and toggles the mode if the argument\nis 'toggle.\n\n(fn &optional ARG)" t nil) back-button-mode)
  command-execute(back-button-mode record)
  execute-extended-command(nil "back-button-mode" "back-button-mo")
  funcall-interactively(execute-extended-command nil "back-button-mode" "back-button-mo")
  call-interactively(execute-extended-command nil nil)
  command-execute(execute-extended-command)

[Silex]

Hum reading the backtrace, I think this is actually a duplicate of https://github.com/myuhe/smartrep.el/issues/14