Looking for guidance to get `gist.el` up and running -- errors

Question

Can anyone please steer me in the right direction to getting gist.el to work properly. Here is the error message:

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  call-process(nil nil #<buffer  *string-output*> nil "config" "github.user")
  apply(call-process nil nil #<buffer  *string-output*> nil ("config" "github.user"))
  process-file(nil nil #<buffer  *string-output*> nil "config" "github.user")
  apply(process-file nil nil #<buffer  *string-output*> nil ("config" "github.user"))
  (let ((standard-output standard-output)) (apply (quote process-file) git nil standard-output nil args))
  (progn (let ((standard-output standard-output)) (apply (quote process-file) git nil standard-output nil args)) (save-current-buffer (set-buffer standard-output) (buffer-string)))
  (unwind-protect (progn (let ((standard-output standard-output)) (apply (quote process-file) git nil standard-output nil args)) (save-current-buffer (set-buffer standard-output) (buffer-string))) (kill-buffer standard-output))
  (let ((standard-output (get-buffer-create (generate-new-buffer-name " *string-output*")))) (unwind-protect (progn (let ((standard-output standard-output)) (apply (quote process-file) git nil standard-output nil args)) (save-current-buffer (set-buffer standard-output) (buffer-string))) (kill-buffer standard-output)))
  (let ((git (executable-find "git"))) (let ((standard-output (get-buffer-create (generate-new-buffer-name " *string-output*")))) (unwind-protect (progn (let ((standard-output standard-output)) (apply (quote process-file) git nil standard-output nil args)) (save-current-buffer (set-buffer standard-output) (buffer-string))) (kill-buffer standard-output))))
  gh-command-to-string("config" "github.user")
  (funcall strip (gh-command-to-string "config" (gh-namespaced-key key)))
  (let ((strip (function (lambda (string) (if (> (length string) 0) (substring string 0 (- ... 1))))))) (funcall strip (gh-command-to-string "config" (gh-namespaced-key key))))
  gh-config("user")
  (or (plist-get (cdr (assoc profile gh-auth-alist)) :username) (plist-get (cdr (assoc profile gh-profile-alist)) :username) (gh-config "user"))
  (let* ((profile (gh-profile-current-profile)) (user (or (plist-get (cdr (assoc profile gh-auth-alist)) :username) (plist-get (cdr (assoc profile gh-profile-alist)) :username) (gh-config "user")))) (if (not user) (progn (setq user (read-string "GitHub username: ")) (gh-set-config "user" user))) (gh-auth-remember profile :username user) user)
  gh-auth-get-username()
  (eieio-oset obj (quote :username) (gh-auth-get-username))
  (or (eieio-oref obj (quote :username)) (eieio-oset obj (quote :username) (gh-auth-get-username)))
  (let ((obj (call-next-method))) (or (eieio-oref obj (quote :username)) (eieio-oset obj (quote :username) (gh-auth-get-username))) obj)
  gh-authenticator(gh-oauth-authenticator "auth")
  apply(gh-authenticator (gh-oauth-authenticator "auth"))
  call-next-method()
  (let ((obj (call-next-method))) (or (eieio-oref obj (quote :token)) (eieio-oset obj (quote :token) (gh-auth-get-oauth-token))) obj)
  gh-oauth-authenticator(gh-oauth-authenticator "auth")
  apply(gh-oauth-authenticator (gh-oauth-authenticator "auth"))
  eieio-generic-call(constructor (gh-oauth-authenticator "auth"))
  constructor(gh-oauth-authenticator "auth")
  apply(constructor gh-oauth-authenticator "auth" nil)
  gh-oauth-authenticator("auth")
  funcall(gh-oauth-authenticator "auth")
  (or (eieio-oref obj (quote :auth)) (funcall gh-api-v3-authenticator "auth"))
  (gh-api-set-default-auth obj (or (eieio-oref obj (quote :auth)) (funcall gh-api-v3-authenticator "auth")))
  (let ((obj (call-next-method)) (gh-profile-current-profile (gh-profile-current-profile))) (eieio-oset obj (quote :profile) (gh-profile-current-profile)) (eieio-oset obj (quote :base) (gh-profile-url)) (gh-api-set-default-auth obj (or (eieio-oref obj (quote :auth)) (funcall gh-api-v3-authenticator "auth"))) obj)
  gh-api-v3(gh-gist-api "api" :sync nil :cache t :num-retries 1)
  apply(gh-api-v3 (gh-gist-api "api" :sync nil :cache t :num-retries 1))
  eieio-generic-call(constructor (gh-gist-api "api" :sync nil :cache t :num-retries 1))
  constructor(gh-gist-api "api" :sync nil :cache t :num-retries 1)
  apply(constructor gh-gist-api "api" (:sync nil :cache t :num-retries 1))
  gh-gist-api("api" :sync nil :cache t :num-retries 1)
  (let ((gh-profile-current-profile (or gh-profile-current-profile (gh-profile-completing-read)))) (gh-gist-api "api" :sync sync :cache t :num-retries 1))
  gist-get-api(nil)
  (let* ((gh-profile-current-profile (or gh-profile-current-profile (gh-profile-completing-read))) (bufname (format "*%s:gists*" gh-profile-current-profile)) (api (gist-get-api nil))) (if force-reload (progn (pcache-clear (eieio-oref api (quote :cache))) (or background (message "Retrieving list of your gists...")))) (if (and background (not (get-buffer bufname))) nil (let ((resp (gh-gist-list api))) (gh-url-add-response-callback resp (let ((--cl-buffer-- (make-symbol "--buffer--"))) (let* ((v --cl-buffer--)) (set v bufname)) (list (quote lambda) (quote (&rest --cl-rest--)) (list (quote apply) (list ... ...) (list ... --cl-buffer--) (quote --cl-rest--))))) (gh-url-add-response-callback resp (let ((--cl-profile-- (make-symbol "--profile--")) (--cl-buffer-- (make-symbol "--buffer--"))) (progn (let* (...) (set v ...)) (let* (...) (set v bufname))) (list (quote lambda) (quote (&rest --cl-rest--)) (list (quote apply) (list ... ...) (list ... --cl-buffer--) (list ... --cl-profile--) (quote --cl-rest--))))))))
  gist-list(nil)
  call-interactively(gist-list record nil)
  command-execute(gist-list record)
  (let ((prefix-arg prefixarg)) (command-execute function (quote record)))
  (progn (let ((prefix-arg prefixarg)) (command-execute function (quote record))))
  (if function (progn (let ((prefix-arg prefixarg)) (command-execute function (quote record)))))
  (let* ((function (and (stringp command-name) (intern-soft command-name))) (binding (and suggest-key-bindings (not executing-kbd-macro) (where-is-internal function overriding-local-map t)))) (setq this-command function) (setq real-this-command function) (if function (progn (let ((prefix-arg prefixarg)) (command-execute function (quote record))))))
  lawlist-execute-extended-command(nil "gist-list")
  call-interactively(lawlist-execute-extended-command nil nil)
  command-execute(lawlist-execute-extended-command)

Answer 1

It looks like (executable-find "git") returned nil, and that eventually caused the error you see. So your problem is that program git is not in your exec-path.

You can look down the debugger stack, starting with noticing that the first arg to call-process needs to be a string (a process name). (Use C-h f call-process to learn this.)