sp-unwrap-sexp throws wrong-type-argument nil in minibuffer

Expected behavior

When working with list expressions in the minibuffer, if I have a set of parenthesis (), and the cursor is inside the expression, sp-unwrap-sexp should unwrap the expression.

Actual behavior

sp-unwrap-sexp throws a (wrong-type-argument stringp nil)

Steps to reproduce the problem

Eval an elisp expression in the minibuffer
Enter an empty expression ()
Move the cursor inside the parenthesis
Try sp-unwrap-sexp

Backtraces if necessary (`M-x toggle-debug-on-error`)

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  string-match("^[\n\11 ]+\\'" nil nil)
  string-match-p("^[\n\11 ]+\\'" nil)
  (if (string-match-p "^[\n\11 ]+\\'" (thing-at-point 'line)) (progn (let ((b (bounds-of-thing-at-point 'line))) (delete-region (car b) (cdr b)))))
  (save-excursion (goto-char new-end) (if (string-match-p "^[\n\11 ]+\\'" (thing-at-point 'line)) (progn (let ((b (bounds-of-thing-at-point 'line))) (delete-region (car b) (cdr b))))) (setq indent-to (point)) (goto-char new-start) (if (string-match-p "^[\n\11 ]+\\'" (thing-at-point 'line)) (progn (let ((b (bounds-of-thing-at-point 'line))) (delete-region (car b) (cdr b))))) (setq indent-from (point)))
  (let ((new-start (let ((struct sexp)) (- (plist-get struct :beg) (length (plist-get struct :prefix))))) (new-end (let ((struct sexp)) (- (- (plist-get struct :end) (length (plist-get struct :cl))) (length (plist-get struct :op)) (length (plist-get struct :prefix))))) indent-from indent-to) (save-excursion (goto-char new-end) (if (string-match-p "^[\n\11 ]+\\'" (thing-at-point 'line)) (progn (let ((b (bounds-of-thing-at-point ...))) (delete-region (car b) (cdr b))))) (setq indent-to (point)) (goto-char new-start) (if (string-match-p "^[\n\11 ]+\\'" (thing-at-point 'line)) (progn (let ((b (bounds-of-thing-at-point ...))) (delete-region (car b) (cdr b))))) (setq indent-from (point))) (if (memq major-mode sp-no-reindent-after-kill-modes) nil (let ((c (current-column)) (i (sp--current-indentation))) (sp--indent-region indent-from indent-to) (sp--back-to-indentation c i))))
  (if no-cleanup nil (let ((new-start (let ((struct sexp)) (- (plist-get struct :beg) (length (plist-get struct :prefix))))) (new-end (let ((struct sexp)) (- (- (plist-get struct :end) (length ...)) (length (plist-get struct :op)) (length (plist-get struct :prefix))))) indent-from indent-to) (save-excursion (goto-char new-end) (if (string-match-p "^[\n\11 ]+\\'" (thing-at-point 'line)) (progn (let ((b ...)) (delete-region (car b) (cdr b))))) (setq indent-to (point)) (goto-char new-start) (if (string-match-p "^[\n\11 ]+\\'" (thing-at-point 'line)) (progn (let ((b ...)) (delete-region (car b) (cdr b))))) (setq indent-from (point))) (if (memq major-mode sp-no-reindent-after-kill-modes) nil (let ((c (current-column)) (i (sp--current-indentation))) (sp--indent-region indent-from indent-to) (sp--back-to-indentation c i)))))
  sp--unwrap-sexp((:beg 7 :end 9 :op "(" :cl ")" :prefix "" :suffix ""))
  (progn (sp--unwrap-sexp ok))
  (if ok (progn (sp--unwrap-sexp ok)))
  (let ((ok (save-excursion (sp-forward-sexp arg)))) (if ok (progn (sp--unwrap-sexp ok))) ok)
  (let ((sp-navigate-consider-symbols nil)) (let ((ok (save-excursion (sp-forward-sexp arg)))) (if ok (progn (sp--unwrap-sexp ok))) ok))
  sp-unwrap-sexp(1)
  funcall-interactively(sp-unwrap-sexp 1)
  call-interactively(sp-unwrap-sexp nil nil)
  command-execute(sp-unwrap-sexp)

Environment & version information

In recent enough smartparens you can call M-x sp-describe-system to generate this report. Please fill manually what we could not detect automatically. Edit the output as you see fit to protect your privacy.

smartparens version: 20230225.1026
Active major-mode: minibuffer
Emacs version (M-x emacs-version): GNU Emacs 28.2 (build 1, aarch64-apple-darwin21.1.0, NS appkit-2113.00 Version 12.0.1 (Build 21A559)) of 2022-09-12
Spacemacs/Evil/Other starterkit (specify which)/Vanilla: Vanilla
OS: Mac OS X

Lead and Potential Resolution

I think that thing-at-point is returning nil in the minibuffer for whatever reason in sp--unwrap-sexp on these lines.

I have no idea if this is expected behaviour for thing-at-point in this context. If it is, then there probably needs to be a check like the following:

        (if-let ((thing (thing-at-point 'line))
                 ((string-match-p "^[\n\t ]+\\'" thing))
                 (b (bounds-of-thing-at-point 'line)))
            (delete-region (car b) (cdr b)))

While this eliminates the error me, if thing-at-point is not supposed to return nil in this situation, then this might not be the right solution.

Fuco1 / smartparens