From 7228488effa78dcb75284cb6d247b24804e0e7f5 Mon Sep 17 00:00:00 2001 From: Stefan Monnier Date: Mon, 2 Apr 2018 00:23:20 -0400 Subject: [PATCH] * lisp/emacs-lisp/debug.el (debug): Don't hang upon error in initial-frame. --- lisp/emacs-lisp/debug.el | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el index f3a927f31cd..e8a3015b8fb 100644 --- a/lisp/emacs-lisp/debug.el +++ b/lisp/emacs-lisp/debug.el @@ -145,9 +145,29 @@ You may call with no args, or you may pass nil as the first arg and any other args you like. In that case, the list of args after the first will be printed into the backtrace buffer." (interactive) - (if inhibit-redisplay - ;; Don't really try to enter debugger within an eval from redisplay. - debugger-value + (cond + (inhibit-redisplay + ;; Don't really try to enter debugger within an eval from redisplay. + debugger-value) + ((and (eq t (framep (selected-frame))) + (equal "initial_terminal" (terminal-name))) + ;; We're in the initial-frame (where `message' just outputs to stdout) so + ;; there's no tty or GUI frame to display the backtrace and interact with + ;; it: just dump a backtrace to stdout. + ;; This happens for example while handling an error in code from + ;; early-init.el with --debug-init. + (message "Error: %S" args) + (let ((print-escape-newlines t) + (print-escape-control-characters t) + (print-level 8) + (print-length 50) + (skip t)) ;Skip the first frame (i.e. the `debug' frame)! + (mapbacktrace (lambda (_evald func args _flags) + (if skip + (setq skip nil) + (message " %S" (cons func args)))) + 'debug))) + (t (unless noninteractive (message "Entering debugger...")) (let (debugger-value @@ -272,7 +292,7 @@ first will be printed into the backtrace buffer." (with-timeout-unsuspend debugger-with-timeout-suspend) (set-match-data debugger-outer-match-data))) (setq debug-on-next-call debugger-step-after-exit) - debugger-value))) + debugger-value)))) (defun debugger--print (obj &optional stream) (condition-case err -- 2.39.2