*Backtrace*.el

Debugger entered--Lisp error: (wrong-type-argument arrayp nil)
  isearch-search()
  isearch-search-and-update()
  (let ((string (concat "\\<" (buffer-substring-no-properties (progn (skip-syntax-backward "w_") (point)) (progn (skip-syntax-forward "w_") (point))) "\\>"))) (if (and isearch-case-fold-search (eq (quote not-yanks) search-upper-case)) (setq string (downcase string))) (setq isearch-string string isearch-message (concat isearch-message (mapconcat (quote isearch-text-char-description) string "")) isearch-yank-flag t) (isearch-search-and-update))
  (progn (let ((string (concat "\\<" (buffer-substring-no-properties (progn (skip-syntax-backward "w_") (point)) (progn (skip-syntax-forward "w_") (point))) "\\>"))) (if (and isearch-case-fold-search (eq (quote not-yanks) search-upper-case)) (setq string (downcase string))) (setq isearch-string string isearch-message (concat isearch-message (mapconcat (quote isearch-text-char-description) string "")) isearch-yank-flag t) (isearch-search-and-update)))
  (if (equal this-command (quote my-isearch-word-at-point)) (progn (let ((string (concat "\\<" (buffer-substring-no-properties (progn ... ...) (progn ... ...)) "\\>"))) (if (and isearch-case-fold-search (eq (quote not-yanks) search-upper-case)) (setq string (downcase string))) (setq isearch-string string isearch-message (concat isearch-message (mapconcat (quote isearch-text-char-description) string "")) isearch-yank-flag t) (isearch-search-and-update))))
  (when (equal this-command (quote my-isearch-word-at-point)) (let ((string (concat "\\<" (buffer-substring-no-properties (progn (skip-syntax-backward "w_") (point)) (progn (skip-syntax-forward "w_") (point))) "\\>"))) (if (and isearch-case-fold-search (eq (quote not-yanks) search-upper-case)) (setq string (downcase string))) (setq isearch-string string isearch-message (concat isearch-message (mapconcat (quote isearch-text-char-description) string "")) isearch-yank-flag t) (isearch-search-and-update)))
  my-isearch-yank-word-hook()
  run-hooks(isearch-mode-hook)
  isearch-mode(t t nil nil)
  isearch-forward-regexp(nil 1)
  call-interactively(isearch-forward-regexp)
  my-isearch-word-at-point()
  call-interactively(my-isearch-word-at-point record nil)
  command-execute(my-isearch-word-at-point record)
  execute-extended-command(nil "my-isearch-word-at-point")
  call-interactively(execute-extended-command nil nil)

repro.md

Repro:

• Place cursor inside first `stuff' in test.txt
• Run M-x my-isearch-word-at-point. Should see success.
• Place cursor inside second `stuff' (or inside `things') in test.txt
• Run M-x my-isearch-word-at-point. Should see failure.

test.txt

things
stuff
stuff