Make `debug' reset `inhibit-read-only' while running

* lisp/emacs-lisp/debug.el (debug): Bind `inhibit-read-only' to
nil in case we're in a context that has bound it to t (bug#26947).

diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 069c7a90ad05ad5fdaa1613a6c3271c635eeb5ab..2007f79634db7ab651120d4ae7fe8c76604dd91b 100644 (file)
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -182,7 +182,11 @@ the debugger will not be entered."
                     (equal "initial_terminal" (terminal-name)))))
           ;; Don't let `inhibit-message' get in our way (especially important if
           ;; `non-interactive-frame' evaluated to a non-nil value.
-          (inhibit-message nil))
+          (inhibit-message nil)
+          ;; We may be entering the debugger from a context that has
+          ;; let-bound `inhibit-read-only', which means that all
+          ;; buffers would be read/write while the debugger is running.
+          (inhibit-read-only nil))
       (unless non-interactive-frame
         (message "Entering debugger..."))
       (let (debugger-value