emacs-29 f7dc0202127: Fix "Text is read-only" on backspacing initial Calc input

[Eli Zaretskii]

branch: emacs-29
commit f7dc0202127a73f83de52b1999a7fe05dd64fff6
Author: George Kuzler <gkuzler@gmail.com>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix "Text is read-only" on backspacing initial Calc input
    
    Immediately after `calc-mode' opens the minibuffer for input
    (because you typed a digit, "e", etc), pressing backspace
    should clear the minibuffer and return you to the *Calculator*
    buffer.  Instead, it leaves the minibuffer as-is and prints the
    message "Text is read-only"; this is because the function used,
    `erase-buffer', tries to erase the read-only minibuffer prompt.
    Using `delete-minibuffer-contents' fixes this, since it doesn't
    attempt to delete the prompt.
    * lisp/calc/calc.el (calcDigit-backspace): Use
    `delete-minibuffer-contents' instead of `erase-buffer'.  (Bug#67395)
    
    Copyright-paperwork-exempt: yes
---
 lisp/calc/calc.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/calc/calc.el b/lisp/calc/calc.el
index f129552c9a4..06ccb0f0cfa 100644
--- a/lisp/calc/calc.el
+++ b/lisp/calc/calc.el
@@ -2477,7 +2477,7 @@ the United States."
 (defun calcDigit-backspace ()
   (interactive)
   (cond ((eq last-command 'calcDigit-start)
-        (erase-buffer))
+        (delete-minibuffer-contents))
        (t (backward-delete-char 1)))
   (if (= (calc-minibuffer-size) 0)
       (progn