* bug#36588: Unable to revert M-x apropos help buffer
@ 2019-07-11 3:31 Stefan Kangas
2019-07-11 14:53 ` Basil L. Contovounesios
0 siblings, 1 reply; 4+ messages in thread
From: Stefan Kangas @ 2019-07-11 3:31 UTC (permalink / raw)
To: 36588
I get an error trying to revert the apropos help buffer on Emacs 27
(current master). I could also reproduce this on 26.1.
Steps to reproduce:
0. emacs -Q
1. M-x apropos RET foo RET
2. C-x o
3. g yes RET
4. Error:
apply: Symbol’s function definition is void: nil
Backtrace:
Debugger entered--Lisp error: (void-function nil)
nil()
apply(nil nil)
help-mode-revert-buffer(t nil)
revert-buffer(t)
funcall-interactively(revert-buffer t)
#<subr call-interactively>(revert-buffer nil nil)
apply(#<subr call-interactively> revert-buffer (nil nil))
call-interactively@ido-cr+-record-current-command(#<subr
call-interactively> revert-buffer nil nil)
apply(call-interactively@ido-cr+-record-current-command #<subr
call-interactively> (revert-buffer nil nil))
call-interactively(revert-buffer nil nil)
command-execute(revert-buffer)
GNU Emacs 27.0.50 (build 5, x86_64-apple-darwin15.6.0, NS
appkit-1404.47 Version 10.11.6 (Build 15G22010)) of 2019-07-11
Thanks,
Stefan Kangas
^ permalink raw reply [flat|nested] 4+ messages in thread
* bug#36588: Unable to revert M-x apropos help buffer
2019-07-11 3:31 bug#36588: Unable to revert M-x apropos help buffer Stefan Kangas
@ 2019-07-11 14:53 ` Basil L. Contovounesios
2019-07-12 5:03 ` Stefan Kangas
0 siblings, 1 reply; 4+ messages in thread
From: Basil L. Contovounesios @ 2019-07-11 14:53 UTC (permalink / raw)
To: Stefan Kangas; +Cc: 36588
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severity 36588 minor
tags 36588 + patch
quit
Stefan Kangas <stefan@marxist.se> writes:
> I get an error trying to revert the apropos help buffer on Emacs 27
> (current master). I could also reproduce this on 26.1.
>
> Steps to reproduce:
> 0. emacs -Q
> 1. M-x apropos RET foo RET
> 2. C-x o
> 3. g yes RET
> 4. Error:
> apply: Symbol’s function definition is void: nil
>
> Backtrace:
> Debugger entered--Lisp error: (void-function nil)
> nil()
> apply(nil nil)
> help-mode-revert-buffer(t nil)
> revert-buffer(t)
> funcall-interactively(revert-buffer t)
> #<subr call-interactively>(revert-buffer nil nil)
> apply(#<subr call-interactively> revert-buffer (nil nil))
> call-interactively@ido-cr+-record-current-command(#<subr
> call-interactively> revert-buffer nil nil)
> apply(call-interactively@ido-cr+-record-current-command #<subr
> call-interactively> (revert-buffer nil nil))
> call-interactively(revert-buffer nil nil)
> command-execute(revert-buffer)
This is because Apropos buffers are set up in apropos-print using
with-output-to-temp-buffer, which by default calls help-mode, which sets
revert-buffer-function permanently-locally to help-mode-revert-buffer.
[Aside: Why is revert-buffer-function permanent-local?]
help-mode-revert-buffer expects the command which generated the Help
buffer to have previously called help-setup-xref. This should be
possible to do in Apropos, but it would be quite ugly as help-setup-xref
needs to be called with the Help buffer current, so Apropos commands
would need to set their own version of help-xref-stack-item before
apropos-print performs the help-setup-xref dance. Besides, Apropos
buffers are not (currently) really Help buffers.
Instead, I propose emulating a simpler version of help-setup-xref
specific to Apropos:
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From 890d2d6c1447f207892be734ab7412b4b471ddb7 Mon Sep 17 00:00:00 2001
From: "Basil L. Contovounesios" <contovob@tcd.ie>
Date: Thu, 11 Jul 2019 15:11:35 +0100
Subject: [PATCH] Support reverting Apropos buffers (bug#36588)
* lisp/apropos.el (apropos--current): New variable akin to
help-xref-stack-item storing information for revert-buffer.
(apropos--revert-buffer): New function.
(apropos-mode): Use it as revert-buffer-function.
(apropos-command, apropos, apropos-library, apropos-value)
(apropos-local-value, apropos-documentation): Set apropos--current
in low-level commands, i.e., those which do not call other commands.
---
lisp/apropos.el | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/lisp/apropos.el b/lisp/apropos.el
index 1b86f5bcde..79e5a1518f 100644
--- a/lisp/apropos.el
+++ b/lisp/apropos.el
@@ -212,6 +212,12 @@ apropos-synonyms
Each element is a list of words where the first word is the standard Emacs
term, and the rest of the words are alternative terms.")
+(defvar apropos--current nil
+ "List of current Apropos function followed by its arguments.
+Used by `apropos--revert-buffer' to regenerate the current
+Apropos buffer. Each Apropos command should ensure it is set
+before `apropos-mode' makes it buffer-local.")
+
\f
;;; Button types used by apropos
@@ -472,10 +478,18 @@ apropos-true-hit-doc
"Return t if DOC is really matched by the current keywords."
(apropos-true-hit doc apropos-all-words))
+(defun apropos--revert-buffer (_ignore-auto noconfirm)
+ "Regenerate current Apropos buffer using `apropos--current'.
+Intended as a value for `revert-buffer-function'."
+ (when (or noconfirm (yes-or-no-p "Revert apropos buffer? "))
+ (apply #'funcall apropos--current)))
+
(define-derived-mode apropos-mode special-mode "Apropos"
"Major mode for following hyperlinks in output of apropos commands.
-\\{apropos-mode-map}")
+\\{apropos-mode-map}"
+ (make-local-variable 'apropos--current)
+ (setq-local revert-buffer-function #'apropos--revert-buffer))
(defvar apropos-multi-type t
"If non-nil, this apropos query concerns multiple types.
@@ -550,6 +564,7 @@ apropos-command
(if (or current-prefix-arg apropos-do-all)
"command or function" "command"))
current-prefix-arg))
+ (setq apropos--current (list #'apropos-command pattern do-all var-predicate))
(apropos-parse-pattern pattern)
(let ((message
(let ((standard-output (get-buffer-create "*Apropos*")))
@@ -628,6 +643,7 @@ apropos
Returns list of symbols and documentation found."
(interactive (list (apropos-read-pattern "symbol")
current-prefix-arg))
+ (setq apropos--current (list #'apropos pattern do-all))
(apropos-parse-pattern pattern)
(apropos-symbols-internal
(apropos-internal apropos-regexp
@@ -670,6 +686,7 @@ apropos-library
libs))
libs)))
(list (completing-read "Describe library: " libs nil t))))
+ (setq apropos--current (list #'apropos-library file))
(let ((symbols nil)
;; (autoloads nil)
(provides nil)
@@ -776,6 +793,7 @@ apropos-value
Returns list of symbols and values found."
(interactive (list (apropos-read-pattern "value")
current-prefix-arg))
+ (setq apropos--current (list #'apropos-value pattern do-all))
(apropos-parse-pattern pattern)
(or do-all (setq do-all apropos-do-all))
(setq apropos-accumulator ())
@@ -815,6 +833,7 @@ apropos-local-value
Optional arg BUFFER (default: current buffer) is the buffer to check."
(interactive (list (apropos-read-pattern "value of buffer-local variable")))
(unless buffer (setq buffer (current-buffer)))
+ (setq apropos--current (list #'apropos-local-value pattern buffer))
(apropos-parse-pattern pattern)
(setq apropos-accumulator ())
(let ((var nil))
@@ -856,6 +875,7 @@ apropos-documentation
;; output, but I cannot see that that is true.
(interactive (list (apropos-read-pattern "documentation")
current-prefix-arg))
+ (setq apropos--current (list #'apropos-documentation pattern do-all))
(apropos-parse-pattern pattern)
(or do-all (setq do-all apropos-do-all))
(setq apropos-accumulator () apropos-files-scanned ())
--
2.20.1
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I don't consider this duplication because, unless Apropos were
completely refactored, setting something like apropos--current would be
necessary either way. This has the added perk of not coupling Apropos
with Help any more than it currently needs to be.
WDYT?
Thanks,
--
Basil
^ permalink raw reply related [flat|nested] 4+ messages in thread
* bug#36588: Unable to revert M-x apropos help buffer
2019-07-11 14:53 ` Basil L. Contovounesios
@ 2019-07-12 5:03 ` Stefan Kangas
2019-08-04 22:45 ` Basil L. Contovounesios
0 siblings, 1 reply; 4+ messages in thread
From: Stefan Kangas @ 2019-07-12 5:03 UTC (permalink / raw)
To: Basil L. Contovounesios; +Cc: 36588
[-- Attachment #1: Type: text/plain, Size: 1397 bytes --]
Basil L. Contovounesios <contovob@tcd.ie> writes:
> This is because Apropos buffers are set up in apropos-print using
> with-output-to-temp-buffer, which by default calls help-mode, which sets
> revert-buffer-function permanently-locally to help-mode-revert-buffer.
>
> [Aside: Why is revert-buffer-function permanent-local?]
>
> help-mode-revert-buffer expects the command which generated the Help
> buffer to have previously called help-setup-xref. This should be
> possible to do in Apropos, but it would be quite ugly as help-setup-xref
> needs to be called with the Help buffer current, so Apropos commands
> would need to set their own version of help-xref-stack-item before
> apropos-print performs the help-setup-xref dance. Besides, Apropos
> buffers are not (currently) really Help buffers.
>
> Instead, I propose emulating a simpler version of help-setup-xref
> specific to Apropos:
>
>
> I don't consider this duplication because, unless Apropos were
> completely refactored, setting something like apropos--current would be
> necessary either way. This has the added perk of not coupling Apropos
> with Help any more than it currently needs to be.
>
> WDYT?
Not familiar with this code, so I can't speak to your solution. I can confirm
it fixes the problem though. Thanks for looking at it so promptly.
I've attached a small patch with a test for this.
Thanks,
Stefan Kangas
[-- Attachment #2: 0001-test-lisp-apropos-tests.el-New-file.patch --]
[-- Type: application/octet-stream, Size: 1681 bytes --]
From 562d2622048be8ac5509d8ccd4b9fd18244fc3a4 Mon Sep 17 00:00:00 2001
From: Stefan Kangas <stefankangas@gmail.com>
Date: Fri, 12 Jul 2019 06:57:29 +0200
Subject: [PATCH] * test/lisp/apropos-tests.el: New file.
---
test/lisp/apropos-tests.el | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
create mode 100644 test/lisp/apropos-tests.el
diff --git a/test/lisp/apropos-tests.el b/test/lisp/apropos-tests.el
new file mode 100644
index 0000000000..44737d902e
--- /dev/null
+++ b/test/lisp/apropos-tests.el
@@ -0,0 +1,34 @@
+;;; apropos-tests.el --- Tests for apropos.el -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2019 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'ert)
+(require 'apropos)
+
+(ert-deftest apropos-tests-revert-buffer ()
+ (with-temp-buffer
+ (apropos "foo")
+ (revert-buffer nil t)
+ (should (looking-at "Type RET on a type label"))))
+
+(provide 'apropos-tests)
+;;; apropos-tests.el ends here
--
2.21.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* bug#36588: Unable to revert M-x apropos help buffer
2019-07-12 5:03 ` Stefan Kangas
@ 2019-08-04 22:45 ` Basil L. Contovounesios
0 siblings, 0 replies; 4+ messages in thread
From: Basil L. Contovounesios @ 2019-08-04 22:45 UTC (permalink / raw)
To: Stefan Kangas; +Cc: 36588-done
tags 36588 fixed
close 36588 27.1
quit
Stefan Kangas <stefan@marxist.se> writes:
> Not familiar with this code, so I can't speak to your solution. I can confirm
> it fixes the problem though. Thanks for looking at it so promptly.
Thanks, I've now pushed the patch to master[1] and am therefore closing
this report.
[1]: Support reverting Apropos buffers (bug#36588)
4cd41ba8de 2019-08-05 01:19:51 +0300
https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=4cd41ba8def704ce3bd2f3806176815fd696fa57
> I've attached a small patch with a test for this.
Thanks, but I'm not sure it's applicable here; see below.
> From 562d2622048be8ac5509d8ccd4b9fd18244fc3a4 Mon Sep 17 00:00:00 2001
> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Fri, 12 Jul 2019 06:57:29 +0200
> Subject: [PATCH] * test/lisp/apropos-tests.el: New file.
[...]
> +(ert-deftest apropos-tests-revert-buffer ()
> + (with-temp-buffer
> + (apropos "foo")
> + (revert-buffer nil t)
> + (should (looking-at "Type RET on a type label"))))
[Nit: Use looking-at-p unless subsequently using the match data.]
I don't currently see a clean way to test this behaviour
non-interactively, as the apropos command takes over the hard-coded
*Apropos* buffer and can pop up new windows and frames (which also
renders the call to with-temp-buffer a no-op, AFAICT). This is far too
intrusive for the ERT case.
Alternatives include refactoring apropos.el to make it more testable,
and adding manual tests under test/manual/, but either of these deserves
its own bug report.
Thanks,
--
Basil
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-08-04 22:45 UTC | newest]
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2019-07-11 3:31 bug#36588: Unable to revert M-x apropos help buffer Stefan Kangas
2019-07-11 14:53 ` Basil L. Contovounesios
2019-07-12 5:03 ` Stefan Kangas
2019-08-04 22:45 ` Basil L. Contovounesios
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