* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode @ 2020-11-29 10:47 Philipp Stephani 2020-11-29 15:27 ` Philipp Stephani 2020-12-07 15:07 ` Mattias Engdegård 0 siblings, 2 replies; 10+ messages in thread From: Philipp Stephani @ 2020-11-29 10:47 UTC (permalink / raw) To: 44942 $ emacs -Q -batch -eval '(progn (defun foo () (error "Boo")) (foo))' Boo Emacs should print a backtrace here to make it possible to debug such errors. It's possible to force Emacs to print a backtrace by binding `debug-on-error', however, that is incorrect because it changes the meaning of `with-demoted-errors' and `condition-case-unless-debug', causing code that would normally work to fail with an error. Instead, `signal' should print a backtrace if in batch mode and if it jumps to the top-level error handler. It looks like this logic could be special-cased in signal_or_quit, similar to the debugger logic. In GNU Emacs 28.0.50 (build 138, x86_64-pc-linux-gnu, GTK+ Version 3.24.22, cairo version 1.16.0) of 2020-11-28 Repository revision: a7825c4be06b7c0b544df34555ecf586276245e6 Repository branch: master Windowing system distributor 'The X.Org Foundation', version 11.0.12008000 System Description: Debian GNU/Linux rodete Configured using: 'configure --enable-gcc-warnings=warn-only --enable-gtk-deprecation-warnings --without-pop --with-mailutils --enable-checking=all --enable-check-lisp-object-type --with-modules 'CFLAGS=-O0 -ggdb3'' Configured features: XPM JPEG TIFF GIF PNG CAIRO SOUND DBUS GSETTINGS GLIB NOTIFY INOTIFY LIBSELINUX GNUTLS FREETYPE HARFBUZZ ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON PDUMPER Important settings: value of $LANG: en_US.utf8 value of $XMODIFIERS: @im=ibus locale-coding-system: utf-8-unix Major mode: Lisp Interaction Minor modes in effect: tooltip-mode: t global-eldoc-mode: t eldoc-mode: t electric-indent-mode: t mouse-wheel-mode: t tool-bar-mode: t menu-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t line-number-mode: t transient-mark-mode: t Load-path shadows: None found. Features: (shadow sort mail-extr emacsbug message rmc dired dired-loaddefs rfc822 mml easymenu mml-sec epa epg epg-config gnus-util rmail rmail-loaddefs time-date mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils phst skeleton derived edmacro kmacro pcase ffap thingatpt url url-proxy url-privacy url-expand url-methods url-history url-cookie url-domsuf url-util url-parse auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs password-cache json map url-vars mailcap rx gnutls puny dbus xml subr-x seq byte-opt gv bytecomp byte-compile cconv compile text-property-search comint ansi-color ring cl-loaddefs cl-lib tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core term/tty-colors frame minibuffer cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese composite charscript charprop case-table epa-hook jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice button loaddefs faces cus-face macroexp files window text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote threads dbusbind inotify dynamic-setting system-font-setting font-render-setting cairo move-toolbar gtk x-toolkit x multi-tty make-network-process emacs) Memory information: ((conses 16 69693 6335) (symbols 48 8576 1) (strings 32 24393 1275) (string-bytes 1 790267) (vectors 16 13891) (vector-slots 8 188843 5960) (floats 8 26 30) (intervals 56 212 0) (buffers 984 11)) -- Google Germany GmbH Erika-Mann-Straße 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg Diese E-Mail ist vertraulich. Falls Sie diese fälschlicherweise erhalten haben sollten, leiten Sie diese bitte nicht an jemand anderes weiter, löschen Sie alle Kopien und Anhänge davon und lassen Sie mich bitte wissen, dass die E-Mail an die falsche Person gesendet wurde. This e-mail is confidential. If you received this communication by mistake, please don’t forward it to anyone else, please erase all copies and attachments, and please let me know that it has gone to the wrong person. ^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-11-29 10:47 bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode Philipp Stephani @ 2020-11-29 15:27 ` Philipp Stephani 2020-12-06 16:50 ` Philipp Stephani 2020-12-07 15:07 ` Mattias Engdegård 1 sibling, 1 reply; 10+ messages in thread From: Philipp Stephani @ 2020-11-29 15:27 UTC (permalink / raw) To: 44942 [-- Attachment #1: Type: text/plain, Size: 756 bytes --] Am So., 29. Nov. 2020 um 11:48 Uhr schrieb Philipp Stephani <p.stephani2@gmail.com>: > > > $ emacs -Q -batch -eval '(progn (defun foo () (error "Boo")) (foo))' > Boo > > Emacs should print a backtrace here to make it possible to debug such > errors. It's possible to force Emacs to print a backtrace by binding > `debug-on-error', however, that is incorrect because it changes the > meaning of `with-demoted-errors' and `condition-case-unless-debug', > causing code that would normally work to fail with an error. Instead, > `signal' should print a backtrace if in batch mode and if it jumps to > the top-level error handler. It looks like this logic could be > special-cased in signal_or_quit, similar to the debugger logic. > I've attached a patch. [-- Attachment #2: 0001-Print-a-backtrace-on-unhandled-errors-in-batch-mode-.patch --] [-- Type: text/x-patch, Size: 4861 bytes --] From 6441ca2ca9ed0233cdf474cc64a860a3cff51222 Mon Sep 17 00:00:00 2001 From: Philipp Stephani <phst@google.com> Date: Sun, 29 Nov 2020 14:24:57 +0100 Subject: [PATCH] Print a backtrace on unhandled errors in batch mode (Bug#44942). * src/eval.c (signal_or_quit): Print a backtrace in batch mode if no error handler was found. * test/src/eval-tests.el (eval-tests/backtrace-in-batch-mode) (eval-tests/backtrace-in-batch-mode/demoted-errors): New unit tests. * etc/NEWS: Document change. --- etc/NEWS | 3 +++ src/eval.c | 15 ++++++++++++++- test/src/eval-tests.el | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 50 insertions(+), 1 deletion(-) diff --git a/etc/NEWS b/etc/NEWS index 2fb33e342e..baae624f27 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -192,6 +192,9 @@ have been replaced with "chat.freenode.net" throughout Emacs. These functions return the connection local value of the respective variables. This can be used for remote hosts. +** Emacs now prints a backtrace when signaling an error in batch mode. This +makes debugging Emacs Lisp scripts run in batch mode easier. + \f * Editing Changes in Emacs 28.1 diff --git a/src/eval.c b/src/eval.c index d9a424b57a..18df484aac 100644 --- a/src/eval.c +++ b/src/eval.c @@ -1709,6 +1709,7 @@ signal_or_quit (Lisp_Object error_symbol, Lisp_Object data, bool keyboard_quit) break; } + bool debugger_called = false; if (/* Don't run the debugger for a memory-full error. (There is no room in memory to do that!) */ !NILP (error_symbol) @@ -1722,7 +1723,7 @@ signal_or_quit (Lisp_Object error_symbol, Lisp_Object data, bool keyboard_quit) if requested". */ || EQ (h->tag_or_ch, Qerror))) { - bool debugger_called + debugger_called = maybe_call_debugger (conditions, error_symbol, data); /* We can't return values to code which signaled an error, but we can continue code which has signaled a quit. */ @@ -1730,6 +1731,18 @@ signal_or_quit (Lisp_Object error_symbol, Lisp_Object data, bool keyboard_quit) return Qnil; } + /* If we're in batch mode, print a backtrace unconditionally to help with + debugging. Make sure to use `debug' unconditionally to not interfere with + ERT or other packages that install custom debuggers. */ + if (!debugger_called && !NILP (error_symbol) + && (NILP (clause) || EQ (h->tag_or_ch, Qerror)) && noninteractive) + { + ptrdiff_t count = SPECPDL_INDEX (); + specbind (Vdebugger, Qdebug); + call_debugger (list2 (Qerror, Fcons (error_symbol, data))); + unbind_to (count, Qnil); + } + if (!NILP (clause)) { Lisp_Object unwind_data diff --git a/test/src/eval-tests.el b/test/src/eval-tests.el index 074f5be1ef..4125573dc6 100644 --- a/test/src/eval-tests.el +++ b/test/src/eval-tests.el @@ -27,6 +27,7 @@ (require 'ert) (eval-when-compile (require 'cl-lib)) +(require 'subr-x) (ert-deftest eval-tests--bug24673 () "Check that Bug#24673 has been fixed." @@ -176,4 +177,36 @@ eval-tests-19790-backquote-comma-dot-substitution expressions works for identifiers starting with period." (should (equal (let ((.x 'identity)) (eval `(,.x 'ok))) 'ok))) +(ert-deftest eval-tests/backtrace-in-batch-mode () + (let ((emacs (expand-file-name invocation-name invocation-directory))) + (skip-unless (file-executable-p emacs)) + (with-temp-buffer + (let ((status (call-process emacs nil t nil + "--quick" "--batch" + (concat "--eval=" + (prin1-to-string + '(progn + (defun foo () (error "Boo")) + (foo))))))) + (should (natnump status)) + (should-not (eql status 0))) + (goto-char (point-min)) + (ert-info ((concat "Process output:\n" (buffer-string))) + (search-forward " foo()") + (search-forward " normal-top-level()"))))) + +(ert-deftest eval-tests/backtrace-in-batch-mode/demoted-errors () + (let ((emacs (expand-file-name invocation-name invocation-directory))) + (skip-unless (file-executable-p emacs)) + (with-temp-buffer + (should (eql 0 (call-process emacs nil t nil + "--quick" "--batch" + (concat "--eval=" + (prin1-to-string + '(with-demoted-errors "Error: %S" + (error "Boo"))))))) + (goto-char (point-min)) + (should (equal (string-trim (buffer-string)) + "Error: (error \"Boo\")"))))) + ;;; eval-tests.el ends here -- 2.29.2.454.gaff20da3a2-goog ^ permalink raw reply related [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-11-29 15:27 ` Philipp Stephani @ 2020-12-06 16:50 ` Philipp Stephani 2020-12-06 16:59 ` Eli Zaretskii 0 siblings, 1 reply; 10+ messages in thread From: Philipp Stephani @ 2020-12-06 16:50 UTC (permalink / raw) To: 44942-done Am So., 29. Nov. 2020 um 16:27 Uhr schrieb Philipp Stephani <p.stephani2@gmail.com>: > > Am So., 29. Nov. 2020 um 11:48 Uhr schrieb Philipp Stephani > <p.stephani2@gmail.com>: > > > > > > $ emacs -Q -batch -eval '(progn (defun foo () (error "Boo")) (foo))' > > Boo > > > > Emacs should print a backtrace here to make it possible to debug such > > errors. It's possible to force Emacs to print a backtrace by binding > > `debug-on-error', however, that is incorrect because it changes the > > meaning of `with-demoted-errors' and `condition-case-unless-debug', > > causing code that would normally work to fail with an error. Instead, > > `signal' should print a backtrace if in batch mode and if it jumps to > > the top-level error handler. It looks like this logic could be > > special-cased in signal_or_quit, similar to the debugger logic. > > > > > I've attached a patch. Pushed to master as commit 40e11743ca. ^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-12-06 16:50 ` Philipp Stephani @ 2020-12-06 16:59 ` Eli Zaretskii 2020-12-07 10:29 ` Philipp Stephani 0 siblings, 1 reply; 10+ messages in thread From: Eli Zaretskii @ 2020-12-06 16:59 UTC (permalink / raw) To: Philipp Stephani; +Cc: 44942 > From: Philipp Stephani <p.stephani2@gmail.com> > Date: Sun, 6 Dec 2020 17:50:17 +0100 > > Am So., 29. Nov. 2020 um 16:27 Uhr schrieb Philipp Stephani > <p.stephani2@gmail.com>: > > > > Am So., 29. Nov. 2020 um 11:48 Uhr schrieb Philipp Stephani > > <p.stephani2@gmail.com>: > > > > > > > > > $ emacs -Q -batch -eval '(progn (defun foo () (error "Boo")) (foo))' > > > Boo > > > > > > Emacs should print a backtrace here to make it possible to debug such > > > errors. It's possible to force Emacs to print a backtrace by binding > > > `debug-on-error', however, that is incorrect because it changes the > > > meaning of `with-demoted-errors' and `condition-case-unless-debug', > > > causing code that would normally work to fail with an error. Instead, > > > `signal' should print a backtrace if in batch mode and if it jumps to > > > the top-level error handler. It looks like this logic could be > > > special-cased in signal_or_quit, similar to the debugger logic. > > > > > > > I've attached a patch. > > Pushed to master as commit 40e11743ca. This is an incompatible change. Is there a way to get back previous behavior? If so, please mention that in NEWS; if not, let's please provide a way to get back the old behavior. Thanks. ^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-12-06 16:59 ` Eli Zaretskii @ 2020-12-07 10:29 ` Philipp Stephani 2020-12-07 10:42 ` Eli Zaretskii 0 siblings, 1 reply; 10+ messages in thread From: Philipp Stephani @ 2020-12-07 10:29 UTC (permalink / raw) To: Eli Zaretskii; +Cc: 44942 Am So., 6. Dez. 2020 um 18:00 Uhr schrieb Eli Zaretskii <eliz@gnu.org>: > > > From: Philipp Stephani <p.stephani2@gmail.com> > > Date: Sun, 6 Dec 2020 17:50:17 +0100 > > > > Am So., 29. Nov. 2020 um 16:27 Uhr schrieb Philipp Stephani > > <p.stephani2@gmail.com>: > > > > > > Am So., 29. Nov. 2020 um 11:48 Uhr schrieb Philipp Stephani > > > <p.stephani2@gmail.com>: > > > > > > > > > > > > $ emacs -Q -batch -eval '(progn (defun foo () (error "Boo")) (foo))' > > > > Boo > > > > > > > > Emacs should print a backtrace here to make it possible to debug such > > > > errors. It's possible to force Emacs to print a backtrace by binding > > > > `debug-on-error', however, that is incorrect because it changes the > > > > meaning of `with-demoted-errors' and `condition-case-unless-debug', > > > > causing code that would normally work to fail with an error. Instead, > > > > `signal' should print a backtrace if in batch mode and if it jumps to > > > > the top-level error handler. It looks like this logic could be > > > > special-cased in signal_or_quit, similar to the debugger logic. > > > > > > > > > > I've attached a patch. > > > > Pushed to master as commit 40e11743ca. > > This is an incompatible change. Is it? In other words, do we guarantee that no stack trace is being printed if debug-on-error is nil? I'd say that parsing error messages is brittle anyway, and we're not obliged to provide stable output. > Is there a way to get back previous > behavior? If so, please mention that in NEWS; if not, let's please > provide a way to get back the old behavior. I'd be OK adding a variable for this, but on the other hand I'm not really convinced that this is really a breaking change (see above). ^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-12-07 10:29 ` Philipp Stephani @ 2020-12-07 10:42 ` Eli Zaretskii 2020-12-07 11:07 ` Philipp Stephani 0 siblings, 1 reply; 10+ messages in thread From: Eli Zaretskii @ 2020-12-07 10:42 UTC (permalink / raw) To: Philipp Stephani; +Cc: 44942 On December 7, 2020 12:29:16 PM GMT+02:00, Philipp Stephani <p.stephani2@gmail.com> wrote: > Am So., 6. Dez. 2020 um 18:00 Uhr schrieb Eli Zaretskii > <eliz@gnu.org>: > > > > > From: Philipp Stephani <p.stephani2@gmail.com> > > > Date: Sun, 6 Dec 2020 17:50:17 +0100 > > > > > > Am So., 29. Nov. 2020 um 16:27 Uhr schrieb Philipp Stephani > > > <p.stephani2@gmail.com>: > > > > > > > Pushed to master as commit 40e11743ca. > > > > This is an incompatible change. > > Is it? In other words, do we guarantee that no stack trace is being > printed if debug-on-error is nil? I'd say that parsing error messages > is brittle anyway, and we're not obliged to provide stable output The behavior did change. Since Emacs doesn't have a formal spec its long-time behavior is a de-facto standard we should strive hard not to break. As Stefan just pointed out, this change already broke 2 tests if we need any proof. > > Is there a way to get back previous > > behavior? If so, please mention that in NEWS; if not, let's please > > provide a way to get back the old behavior. > > I'd be OK adding a variable for this, but on the other hand I'm not > really convinced that this is really a breaking change (see above). Yes, we do need to be able to get back the old bdhavior. ^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-12-07 10:42 ` Eli Zaretskii @ 2020-12-07 11:07 ` Philipp Stephani 2020-12-07 15:45 ` Eli Zaretskii 0 siblings, 1 reply; 10+ messages in thread From: Philipp Stephani @ 2020-12-07 11:07 UTC (permalink / raw) To: Eli Zaretskii; +Cc: 44942 Am Mo., 7. Dez. 2020 um 11:42 Uhr schrieb Eli Zaretskii <eliz@gnu.org>: > > On December 7, 2020 12:29:16 PM GMT+02:00, Philipp Stephani <p.stephani2@gmail.com> wrote: > > Am So., 6. Dez. 2020 um 18:00 Uhr schrieb Eli Zaretskii > > <eliz@gnu.org>: > > > > > > > From: Philipp Stephani <p.stephani2@gmail.com> > > > > Date: Sun, 6 Dec 2020 17:50:17 +0100 > > > > > > > > Am So., 29. Nov. 2020 um 16:27 Uhr schrieb Philipp Stephani > > > > <p.stephani2@gmail.com>: > > > > > > > > > Pushed to master as commit 40e11743ca. > > > > > > This is an incompatible change. > > > > Is it? In other words, do we guarantee that no stack trace is being > > printed if debug-on-error is nil? I'd say that parsing error messages > > is brittle anyway, and we're not obliged to provide stable output > > The behavior did change. Since Emacs doesn't have a formal spec its long-time behavior is a de-facto standard we should strive hard not to break. As Stefan just pointed out, this change already broke 2 tests if we need any proof. > > > > Is there a way to get back previous > > > behavior? If so, please mention that in NEWS; if not, let's please > > > provide a way to get back the old behavior. > > > > I'd be OK adding a variable for this, but on the other hand I'm not > > really convinced that this is really a breaking change (see above). > > Yes, we do need to be able to get back the old bdhavior. Fair enough, I've added a new boolean variable for this. ^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-12-07 11:07 ` Philipp Stephani @ 2020-12-07 15:45 ` Eli Zaretskii 0 siblings, 0 replies; 10+ messages in thread From: Eli Zaretskii @ 2020-12-07 15:45 UTC (permalink / raw) To: Philipp Stephani; +Cc: 44942 > From: Philipp Stephani <p.stephani2@gmail.com> > Date: Mon, 7 Dec 2020 12:07:48 +0100 > Cc: 44942@debbugs.gnu.org > > > Yes, we do need to be able to get back the old bdhavior. > > Fair enough, I've added a new boolean variable for this. Thank you. ^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-11-29 10:47 bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode Philipp Stephani 2020-11-29 15:27 ` Philipp Stephani @ 2020-12-07 15:07 ` Mattias Engdegård 2020-12-07 15:29 ` Philipp Stephani 1 sibling, 1 reply; 10+ messages in thread From: Mattias Engdegård @ 2020-12-07 15:07 UTC (permalink / raw) To: Philipp Stephani, Eli Zaretskii; +Cc: 44942 This is a fine and welcome improvement, thank you! Perhaps it needn't say 'Debugger entered' though? It's a bit misleading and not really true from the user's point of view. ^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode 2020-12-07 15:07 ` Mattias Engdegård @ 2020-12-07 15:29 ` Philipp Stephani 0 siblings, 0 replies; 10+ messages in thread From: Philipp Stephani @ 2020-12-07 15:29 UTC (permalink / raw) To: Mattias Engdegård; +Cc: 44942 Am Mo., 7. Dez. 2020 um 16:07 Uhr schrieb Mattias Engdegård <mattiase@acm.org>: > > This is a fine and welcome improvement, thank you! Perhaps it needn't say 'Debugger entered' though? It's a bit misleading and not really true from the user's point of view. > Yes, that would be great :-) Unfortunately I haven't found a trivial way to separate the backtrace-printing that `debug' does from its other actions, but I'm planning to take a second look at the debug.el code. ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2020-12-07 15:45 UTC | newest] Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-11-29 10:47 bug#44942: 28.0.50; Emacs should print a backtrace on uncaught errors in batch mode Philipp Stephani 2020-11-29 15:27 ` Philipp Stephani 2020-12-06 16:50 ` Philipp Stephani 2020-12-06 16:59 ` Eli Zaretskii 2020-12-07 10:29 ` Philipp Stephani 2020-12-07 10:42 ` Eli Zaretskii 2020-12-07 11:07 ` Philipp Stephani 2020-12-07 15:45 ` Eli Zaretskii 2020-12-07 15:07 ` Mattias Engdegård 2020-12-07 15:29 ` Philipp Stephani
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