From: Alan Mackenzie <acm@muc.de>
To: 65622@debbugs.gnu.org
Subject: bug#65622: Inappropriate suppression of backtrace on an error
Date: Wed, 30 Aug 2023 13:08:26 +0000 [thread overview]
Message-ID: <ZO8_SpFzaWeF_7xe@ACM> (raw)
Hello, Emacs.
On a recent master branch Emacs:
(i) emacs -Q
(ii) Insert the following into *scratch*:
(defmacro hash-if (condition then-form &rest else-forms)
"A conditional compilation macro analogous to C's #if.
Evaluate CONDITION at macro-expansion time. If it is non-nil,
expand the macro to THEN-FORM. Otherwise expand it to ELSE-FORMS
enclosed in a `progn' form. ELSE-FORMS may be empty."
(declare (indent 2)
(debug (form sexp &rest sexp)))
(if (eval condition lexical-binding)
then-form
(cons 'progn else-forms)))
(defun foo (bar)
(hash-if (< emacs-major-version 19)
(car bar)
(cons bar bar)))
(iii) Evaluate hash-if by putting point after it and doing C-x C-e.
(iv) Attempt to instrument foo for edebug by putting point inside foo and
doing C-u C-M-x. This throws the error: "Ignoring macroexpansion
error: (void-function edebug-after)".
(v) Set debug-on-error to t with M-: (setq debug-on-error t).
(vi) Repeat (iv). This throws the same error, without a backtrace. This
lack of a backtrace is a bug.
(vii) This backtrace is almost certainly being suppressed by a frivolous
condition-case, whose main purpose appears to be making debugging more
difficult. ;-)
(viii) There would appear to be no justification for "ignoring" the error
(void-function edebug-after). Such error should not occur, and needs
debugging.
--
Alan Mackenzie (Nuremberg, Germany).
next reply other threads:[~2023-08-30 13:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-30 13:08 Alan Mackenzie [this message]
2023-08-30 23:16 ` bug#65622: Inappropriate suppression of backtrace on an error Michael Heerdegen
2023-08-31 7:41 ` Gerd Möllmann
2023-08-31 7:49 ` Eli Zaretskii
2023-08-31 8:21 ` Gerd Möllmann
2023-09-20 15:55 ` Alan Mackenzie
2023-09-21 1:44 ` Michael Heerdegen
2023-09-21 13:24 ` Alan Mackenzie
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