bug#40728: 27.0.91; Removed public functions from debugger.el

bug#40728: 27.0.91; Removed public functions from debugger.el

[Philipp Stephani]

It looks like the following public functions were deleted from
debugger.el between Emacs 26 and 27: debug-help-follow,
debugger-insert-backtrace, debugger-toggle-locals.  All three were
public (didn't contain a double hyphen) and documented, therefore meant
for general use.  I don't think we should remove such functions (and
break users' workflows that rely on them) without a strong reason.
Please consider restoring these functions for Emacs 27.


In GNU Emacs 27.0.91 (build 3, x86_64-pc-linux-gnu, GTK+ Version 3.24.13)
 of 2020-04-20
Repository revision: a1040861f118881004f59866111f64cd0ae03b7a
Repository branch: emacs-27
Windowing system distributor 'The X.Org Foundation', version 11.0.12004000
System Description: Debian GNU/Linux rodete

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --enable-checking=all --enable-gtk-deprecation-warnings
 --enable-gcc-warnings=warn-only --enable-check-lisp-object-type
 --with-mailutils --without-pop 'CFLAGS=-O0 -g3' LDFLAGS=-g3'

Configured features:
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LIBSELINUX GNUTLS FREETYPE HARFBUZZ XFT ZLIB TOOLKIT_SCROLL_BARS GTK3
X11 XDBE XIM MODULES THREADS PDUMPER GMP

Important settings:
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  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
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  global-font-lock-mode: t
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  auto-composition-mode: t
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Load-path shadows:
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Memory information:
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bug#40728: 27.0.91; Removed public functions from debugger.el

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Mon, 20 Apr 2020 10:21:03 +0200
> 
> 
> It looks like the following public functions were deleted from
> debugger.el between Emacs 26 and 27: debug-help-follow,
> debugger-insert-backtrace, debugger-toggle-locals.  All three were
> public (didn't contain a double hyphen) and documented, therefore meant
> for general use.  I don't think we should remove such functions (and
> break users' workflows that rely on them) without a strong reason.
> Please consider restoring these functions for Emacs 27.

Gemini, could you please write replacements for the functions you
removed, or defalias them to some equivalent replacements?  I agree
that public functions should not be removed, not without deprecating
them first (if indeed they don't make sense).

Thanks.

bug#40728: 27.0.91; Removed public functions from debugger.el

[Gemini Lasswell]

[-- Attachment #1: Type: text/plain, Size: 344 bytes --]

Eli Zaretskii <eliz@gnu.org> writes:

> Gemini, could you please write replacements for the functions you
> removed, or defalias them to some equivalent replacements?  I agree
> that public functions should not be removed, not without deprecating
> them first (if indeed they don't make sense).

Here is a patch to bring those functions back.


[-- Attachment #2: 0001-Restore-some-public-functions-to-debug.el-Bug-40728.patch --]
[-- Type: text/plain, Size: 3693 bytes --]

From 6e1141592bc259bab9c61f3212351c92d0eb16e7 Mon Sep 17 00:00:00 2001
From: Gemini Lasswell <gazally@runbox.com>
Date: Sun, 26 Apr 2020 10:14:38 -0700
Subject: [PATCH] Restore some public functions to debug.el (Bug#40728)

In "Add backtrace-mode and use it in the debugger, ERT and Edebug", on
19 June 2018, three public functions in debug.el were removed.
Restore them so as not to break users' workflows.  Since
backtrace-mode now provides the functionality that used to come from
the buttons created by debugger-insert-backtrace, it is now obsolete.

* lisp/emacs-lisp/debug.el (debugger-insert-backtrace): New function.
Mark it as obsolete.
(debugger-toggle-locals, debug-help-follow): New aliases.

* lisp/emacs-lisp/backtrace.el (backtrace--to-string): New function.
(backtrace-to-string): Use it.  Fix whitespace.
---
 lisp/emacs-lisp/backtrace.el | 11 +++++++----
 lisp/emacs-lisp/debug.el     | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/lisp/emacs-lisp/backtrace.el b/lisp/emacs-lisp/backtrace.el
index 37dad8db16..5874ba72fc 100644
--- a/lisp/emacs-lisp/backtrace.el
+++ b/lisp/emacs-lisp/backtrace.el
@@ -922,11 +922,15 @@ backtrace
   (princ (backtrace-to-string (backtrace-get-frames 'backtrace)))
   nil)
 
-(defun backtrace-to-string(&optional frames)
+(defun backtrace-to-string (&optional frames)
   "Format FRAMES, a list of `backtrace-frame' objects, for output.
 Return the result as a string.  If FRAMES is nil, use all
 function calls currently active."
-  (unless frames (setq frames (backtrace-get-frames 'backtrace-to-string)))
+  (substring-no-properties
+   (backtrace--to-string
+    (or frames (backtrace-get-frames 'backtrace-to-string)))))
+
+(defun backtrace--to-string (frames)
   (let ((backtrace-fontify nil))
     (with-temp-buffer
       (backtrace-mode)
@@ -934,8 +938,7 @@ backtrace-to-string
             backtrace-frames frames
             backtrace-print-function #'cl-prin1)
       (backtrace-print)
-      (substring-no-properties (filter-buffer-substring (point-min)
-                                                        (point-max))))))
+      (filter-buffer-substring (point-min) (point-max)))))
 
 (provide 'backtrace)
 
diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index ed28997292..14957eae0f 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -320,6 +320,17 @@ debugger--print
      (message "Error in debug printer: %S" err)
      (prin1 obj stream))))
 
+(make-obsolete 'debugger-insert-backtrace
+               "use a `backtrace-mode' buffer or `backtrace-to-string'."
+               "Emacs 27.1")
+
+(defun debugger-insert-backtrace (frames do-xrefs)
+  "Format and insert the backtrace FRAMES at point.
+Make functions into cross-reference buttons if DO-XREFS is non-nil."
+  (insert (if do-xrefs
+              (backtrace--to-string frames)
+            (backtrace-to-string frames))))
+
 (defun debugger-setup-buffer (args)
   "Initialize the `*Backtrace*' buffer for entry to the debugger.
 That buffer should be current already and in debugger-mode."
@@ -527,6 +538,8 @@ debugger-eval-expression
           (let ((str (eval-expression-print-format val)))
             (if str (princ str t))))))))
 
+(defalias 'debugger-toggle-locals 'backtrace-toggle-locals)
+
 \f
 (defvar debugger-mode-map
   (let ((map (make-keymap)))
@@ -621,6 +634,8 @@ debugger-record-expression
 	     (buffer-substring (line-beginning-position 0)
 			       (line-end-position 0)))))
 
+(defalias 'debug-help-follow 'backtrace-help-follow-symbol)
+
 \f
 ;; When you change this, you may also need to change the number of
 ;; frames that the debugger skips.
-- 
2.23.1

bug#40728: 27.0.91; Removed public functions from debugger.el

[Eli Zaretskii]

> From: Gemini Lasswell <gazally@runbox.com>
> Cc: Philipp Stephani <p.stephani2@gmail.com>,  40728@debbugs.gnu.org
> Date: Mon, 27 Apr 2020 13:54:27 -0700
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Gemini, could you please write replacements for the functions you
> > removed, or defalias them to some equivalent replacements?  I agree
> > that public functions should not be removed, not without deprecating
> > them first (if indeed they don't make sense).
> 
> Here is a patch to bring those functions back.

Thanks!

Philipp, any comments?  If not, I'd like to install this on the
release branch.

bug#40728: 27.0.91; Removed public functions from debugger.el

[Philipp Stephani]

Am Di., 28. Apr. 2020 um 08:32 Uhr schrieb Eli Zaretskii <eliz@gnu.org>:
>
> > From: Gemini Lasswell <gazally@runbox.com>
> > Cc: Philipp Stephani <p.stephani2@gmail.com>,  40728@debbugs.gnu.org
> > Date: Mon, 27 Apr 2020 13:54:27 -0700
> >
> > Eli Zaretskii <eliz@gnu.org> writes:
> >
> > > Gemini, could you please write replacements for the functions you
> > > removed, or defalias them to some equivalent replacements?  I agree
> > > that public functions should not be removed, not without deprecating
> > > them first (if indeed they don't make sense).
> >
> > Here is a patch to bring those functions back.
>
> Thanks!
>
> Philipp, any comments?  If not, I'd like to install this on the
> release branch.

I haven't tested the patch in detail, but it looks fine, thanks.
I guess you want to use `define-obsolete-function-alias' instead of
`defalias' to mark the aliases as obsolete as well.
The commit message should contain a magic string such as "Don't merge
to master" to prevent reinstating the functions in Emacs 28.

bug#40728: 27.0.91; Removed public functions from debugger.el

[Stefan Kangas]

Philipp Stephani <p.stephani2@gmail.com> writes:

> Am Di., 28. Apr. 2020 um 08:32 Uhr schrieb Eli Zaretskii <eliz@gnu.org>:
>>
>> > From: Gemini Lasswell <gazally@runbox.com>
>> > Cc: Philipp Stephani <p.stephani2@gmail.com>,  40728@debbugs.gnu.org
>> > Date: Mon, 27 Apr 2020 13:54:27 -0700
>> >
>> > Eli Zaretskii <eliz@gnu.org> writes:
>> >
>> > > Gemini, could you please write replacements for the functions you
>> > > removed, or defalias them to some equivalent replacements?  I agree
>> > > that public functions should not be removed, not without deprecating
>> > > them first (if indeed they don't make sense).
>> >
>> > Here is a patch to bring those functions back.
>>
>> Thanks!
>>
>> Philipp, any comments?  If not, I'd like to install this on the
>> release branch.
>
> I haven't tested the patch in detail, but it looks fine, thanks.
> I guess you want to use `define-obsolete-function-alias' instead of
> `defalias' to mark the aliases as obsolete as well.
> The commit message should contain a magic string such as "Don't merge
> to master" to prevent reinstating the functions in Emacs 28.

It seems like the patch here was never installed on the release branch.

Should it be?

Best regards,
Stefan Kangas

bug#40728: 27.0.91; Removed public functions from debugger.el

[Lars Ingebrigtsen]

Stefan Kangas <stefan@marxist.se> writes:

>> I haven't tested the patch in detail, but it looks fine, thanks.
>> I guess you want to use `define-obsolete-function-alias' instead of
>> `defalias' to mark the aliases as obsolete as well.
>> The commit message should contain a magic string such as "Don't merge
>> to master" to prevent reinstating the functions in Emacs 28.

I applied the patch now, but I forgot about this bit...  but...  I think
they should be merged to Emacs 28?  They shouldn't disappear again
between Emacs 27 and Emacs 28.

I've made the aliases obsolete, though.

> It seems like the patch here was never installed on the release branch.

Done now.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#40728: 27.0.91; Removed public functions from debugger.el

[Philipp Stephani]

Am Do., 1. Okt. 2020 um 20:04 Uhr schrieb Lars Ingebrigtsen <larsi@gnus.org>:
>
> Stefan Kangas <stefan@marxist.se> writes:
>
> >> I haven't tested the patch in detail, but it looks fine, thanks.
> >> I guess you want to use `define-obsolete-function-alias' instead of
> >> `defalias' to mark the aliases as obsolete as well.
> >> The commit message should contain a magic string such as "Don't merge
> >> to master" to prevent reinstating the functions in Emacs 28.
>
> I applied the patch now, but I forgot about this bit...  but...  I think
> they should be merged to Emacs 28?  They shouldn't disappear again
> between Emacs 27 and Emacs 28.
>
> I've made the aliases obsolete, though.
>
> > It seems like the patch here was never installed on the release branch.
>
> Done now.

Unfortunately I think this is now too late. Emacs 27.1 has been
released, the incompatible change has been made, and package authors
will need to cope with it.