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

diff --git a/lisp/calc/calc.el b/lisp/calc/calc.el
index f129552c9a41852123430ee32519d99a1a3fe44b..06ccb0f0cfa72c6ba3fe37584cfd2c7c0b4cc279 100644 (file)
--- 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