Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

Hello,

when you have set `wdired-use-interactive-rename' to non-nil, and you
add something to the front of a filename when in wdired-mode, you get
an error after hitting C-c C-c.  Here is a recipe for emacs -Q:

- dired a directory where you are allowed to change file names
- M-: (progn (require 'wdired) (setq wdired-use-interactive-rename t)) RET
- M-x wdired-change-to-wdired-mode
- go to any file
- prepend any string to its name
- C-c C-c

This will fail either with an error, or an attempt to rename a
non-existent file (whose name is a substring of the file you actually
wanted to rename).

Here is a backtrace where I got an error:

Debugger entered--Lisp error: (args-out-of-range 0 0)
  replace-match("newlines.el" t t)
  (let ((inhibit-read-only t)) (dired-move-to-filename) (search-forward (wdired-get-filename t) nil t) (replace-match (file-name-nondirectory filename-ori) t t))
  (progn (setq done t) (let ((inhibit-read-only t)) (dired-move-to-filename) (search-forward (wdired-get-filename t) nil t) (replace-match (file-name-nondirectory filename-ori) t t)) (dired-do-create-files-regexp (function dired-rename-file) "Move" 1 ".*" filename-new nil t))
  (if (equal curr-filename filename-ori) (progn (setq done t) (let ((inhibit-read-only t)) (dired-move-to-filename) (search-forward (wdired-get-filename t) nil t) (replace-match (file-name-nondirectory filename-ori) t t)) (dired-do-create-files-regexp (function dired-rename-file) "Move" 1 ".*" filename-new nil t)) (forward-line -1))
  (while (and (not done) (not (bobp))) (setq curr-filename (wdired-get-filename nil t)) (if (equal curr-filename filename-ori) (progn (setq done t) (let ((inhibit-read-only t)) (dired-move-to-filename) (search-forward (wdired-get-filename t) nil t) (replace-match (file-name-nondirectory filename-ori) t t)) (dired-do-create-files-regexp (function dired-rename-file) "Move" 1 ".*" filename-new nil t)) (forward-line -1)))
  (let ((done nil) curr-filename) (while (and (not done) (not (bobp))) (setq curr-filename (wdired-get-filename nil t)) (if (equal curr-filename filename-ori) (progn (setq done t) (let ((inhibit-read-only t)) (dired-move-to-filename) (search-forward (wdired-get-filename t) nil t) (replace-match (file-name-nondirectory filename-ori) t t)) (dired-do-create-files-regexp (function dired-rename-file) "Move" 1 ".*" filename-new nil t)) (forward-line -1))))
  (save-excursion (goto-char (point-max)) (forward-line -1) (let ((done nil) curr-filename) (while (and (not done) (not (bobp))) (setq curr-filename (wdired-get-filename nil t)) (if (equal curr-filename filename-ori) (progn (setq done t) (let ((inhibit-read-only t)) (dired-move-to-filename) (search-forward (wdired-get-filename t) nil t) (replace-match (file-name-nondirectory filename-ori) t t)) (dired-do-create-files-regexp (function dired-rename-file) "Move" 1 ".*" filename-new nil t)) (forward-line -1)))))
  wdired-search-and-rename("/home/micha/today/Test/newlines.el" "/home/micha/today/Test/znewlines.el")
  (if wdired-use-interactive-rename (wdired-search-and-rename file-ori file-new) (require (quote dired-aux)) (condition-case err (let ((dired-backup-overwrite nil)) (dired-rename-file file-ori file-new overwrite)) (error (setq errors (1+ errors)) (dired-log (concat "Rename `" file-ori "' to `" file-new "' failed:\n%s\n") err))))
  (let ((file-ori (car rename))) (if wdired-use-interactive-rename (wdired-search-and-rename file-ori file-new) (require (quote dired-aux)) (condition-case err (let ((dired-backup-overwrite nil)) (dired-rename-file file-ori file-new overwrite)) (error (setq errors (1+ errors)) (dired-log (concat "Rename `" file-ori "' to `" file-new "' failed:\n%s\n") err)))))
  (cond ((rassoc file-new renames) (error "Trying to rename 2 files to the same name")) ((assoc file-new renames) (setq residue (cons rename residue))) ((and (assoc file-new residue) (file-exists-p file-new)) (if (or progress renames) (setq residue (cons rename residue)) (message "Circular renaming: using temporary file name") (let ((tmp (make-temp-name file-new))) (setq renames (cons (cons (car rename) tmp) renames)) (setq residue (cons (cons tmp file-new) residue))))) (t (setq progress t) (let ((file-ori (car rename))) (if wdired-use-interactive-rename (wdired-search-and-rename file-ori file-new) (require (quote dired-aux)) (condition-case err (let ((dired-backup-overwrite nil)) (dired-rename-file file-ori file-new overwrite)) (error (setq errors (1+ errors)) (dired-log (concat "Rename `" file-ori "' to `" file-new "' failed:\n%s\n") err)))))))
  (let* ((rename (car (prog1 renames (setq renames (cdr renames))))) (file-new (cdr rename))) (cond ((rassoc file-new renames) (error "Trying to rename 2 files to the same name")) ((assoc file-new renames) (setq residue (cons rename residue))) ((and (assoc file-new residue) (file-exists-p file-new)) (if (or progress renames) (setq residue (cons rename residue)) (message "Circular renaming: using temporary file name") (let ((tmp (make-temp-name file-new))) (setq renames (cons (cons ... tmp) renames)) (setq residue (cons (cons tmp file-new) residue))))) (t (setq progress t) (let ((file-ori (car rename))) (if wdired-use-interactive-rename (wdired-search-and-rename file-ori file-new) (require (quote dired-aux)) (condition-case err (let (...) (dired-rename-file file-ori file-new overwrite)) (error (setq errors ...) (dired-log ... err))))))))
  (while (or renames (prog1 (setq renames residue) (setq progress nil) (setq residue nil))) (let* ((rename (car (prog1 renames (setq renames (cdr renames))))) (file-new (cdr rename))) (cond ((rassoc file-new renames) (error "Trying to rename 2 files to the same name")) ((assoc file-new renames) (setq residue (cons rename residue))) ((and (assoc file-new residue) (file-exists-p file-new)) (if (or progress renames) (setq residue (cons rename residue)) (message "Circular renaming: using temporary file name") (let ((tmp ...)) (setq renames (cons ... renames)) (setq residue (cons ... residue))))) (t (setq progress t) (let ((file-ori (car rename))) (if wdired-use-interactive-rename (wdired-search-and-rename file-ori file-new) (require (quote dired-aux)) (condition-case err (let ... ...) (error ... ...))))))))
  (let ((residue nil) (progress nil) (errors 0) (overwrite (or (not wdired-confirm-overwrite) 1))) (while (or renames (prog1 (setq renames residue) (setq progress nil) (setq residue nil))) (let* ((rename (car (prog1 renames (setq renames ...)))) (file-new (cdr rename))) (cond ((rassoc file-new renames) (error "Trying to rename 2 files to the same name")) ((assoc file-new renames) (setq residue (cons rename residue))) ((and (assoc file-new residue) (file-exists-p file-new)) (if (or progress renames) (setq residue (cons rename residue)) (message "Circular renaming: using temporary file name") (let (...) (setq renames ...) (setq residue ...)))) (t (setq progress t) (let ((file-ori ...)) (if wdired-use-interactive-rename (wdired-search-and-rename file-ori file-new) (require ...) (condition-case err ... ...))))))) errors)
  wdired-do-renames((("/home/micha/today/Test/newlines.el" . "/home/micha/today/Test/znewlines.el")))
  (+ errors (wdired-do-renames files-renamed))
  (setq errors (+ errors (wdired-do-renames files-renamed)))
  (progn (setq errors (+ errors (wdired-do-renames files-renamed))))
  (if files-renamed (progn (setq errors (+ errors (wdired-do-renames files-renamed)))))
  (let ((changes nil) (errors 0) files-deleted files-renamed some-file-names-unchanged file-old file-new tmp-value) (save-excursion (if (and wdired-allow-to-redirect-links (fboundp (quote make-symbolic-link))) (progn (setq tmp-value (wdired-do-symlink-changes)) (setq errors (cdr tmp-value)) (setq changes (car tmp-value)))) (if (and wdired-allow-to-change-permissions (boundp (quote wdired-col-perm))) (progn (setq tmp-value (wdired-do-perm-changes)) (setq errors (+ errors (cdr tmp-value))) (setq changes (or changes (car tmp-value))))) (goto-char (point-max)) (while (not (bobp)) (setq file-old (wdired-get-filename nil t)) (if file-old (progn (setq file-new (wdired-get-filename)) (if (equal file-new file-old) (setq some-file-names-unchanged t) (setq changes t) (if (not file-new) (setq files-deleted ...) (setq files-renamed ...))))) (forward-line -1))) (if files-renamed (progn (setq errors (+ errors (wdired-do-renames files-renamed))))) (if changes (progn (if (and (stringp dired-directory) (not (file-directory-p dired-directory)) (null some-file-names-unchanged) (= (length files-renamed) 1)) (progn (setq dired-directory (cdr (car files-renamed))))) (revert-buffer)) (let ((inhibit-read-only t)) (remove-text-properties (point-min) (point-max) (quote (old-name nil end-name nil old-link nil end-link nil end-perm nil old-perm nil perm-changed nil))) (message "(No changes to be performed)"))) (if files-deleted (progn (wdired-flag-for-deletion files-deleted))) (if (> errors 0) (progn (dired-log-summary (format "%d rename actions failed" errors) nil))))
  wdired-finish-edit()
  call-interactively(wdired-finish-edit nil nil)

I located the problem in `wdired-search-and-rename':

(defun wdired-search-and-rename (filename-ori filename-new)
  (save-excursion
    (goto-char (point-max))
    (forward-line -1)
    (let ((done nil)
	  curr-filename)
      (while (and (not done) (not (bobp)))
        (setq curr-filename (wdired-get-filename nil t))
        (if (equal curr-filename filename-ori)
            (progn
              (setq done t)
              (let ((inhibit-read-only t))
                (dired-move-to-filename)  ;; <--------------- here
                (search-forward (wdired-get-filename t) nil t)
                (replace-match (file-name-nondirectory filename-ori) t t))
              (dired-do-create-files-regexp
               (function dired-rename-file)
               "Move" 1 ".*" filename-new nil t))
	  (forward-line -1))))))

It is an error to use `dired-move-to-filename' in this context.
`dired-move-to-filename' looks for text with the `dired-filename' text
property.  But this is wrong if you have added text to the beginning
of a filename, because then, the first appearance of the
`dired-filename' text property is not the beginning of the edited
filename.  In the backtrace above, the `search-forward' fails, and
thus `replace-match' uses invalid match-data.


Fix: The following patch works for me: