GNU bug report logs -
#61925
30.0.50; normal-mode does not set up local variables in temporary buffers (scratch, with-temp-buffer)
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Reported by: Wolfgang Scherer <Wolfgang.Scherer <at> gmx.de>
Date: Thu, 2 Mar 2023 23:12:02 UTC
Severity: normal
Tags: notabug
Found in version 30.0.50
Done: Stefan Kangas <stefankangas <at> gmail.com>
Bug is archived. No further changes may be made.
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(Thu, 02 Mar 2023 23:12:02 GMT)
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Wolfgang Scherer <Wolfgang.Scherer <at> gmx.de>:
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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):
The command `normal-mode' does not set file local variables, if a
buffer does not have a `buffer-file-name'. This affects *scratch* and
buffers created using `with-temp-buffer'.
The behavior changed at some time between Emacs version 20.5.2.2 and 20.6.3.
See output from various Emacs versions further below.
If that was an intentional change, it should be prominently documented
to avoid the confusion when examples do not work in a *scratch* buffer.
I would even recommend a warning prompt in normal-mode, when called
interactively.
After executing the the test expression
(let ((expected-value (not (default-value 'truncate-lines)))
sep)
(princ "# |:sec:| local variables test\n")
(dolist (fn (list nil "fake-file-name"))
(with-temp-buffer
(insert (format (concat ";; -*-"
" mode: fundamental;"
" truncate-lines: %S;"
" -*-")
expected-value))
(let ((buffer-file-name fn))
(normal-mode)
(princ (format (concat sep
".. code-block:: elisp\n"
"\n"
" ;; emacs-version: %s\n"
" ;; buffer-file-name: %S\n"
" ;; truncate-lines: %S\n"
" ;; expected-value: %S\n")
emacs-version buffer-file-name
expected-value truncate-lines))))
(setq sep "\n"))
(princ "# |:sec:| local variables test\n"))
the following output is shown in the *Message* buffer:
# |:sec:| local variables test
.. code-block:: elisp
;; emacs-version: 30.0.50
;; buffer-file-name: nil
;; truncate-lines: t
;; expected-value: nil
.. code-block:: elisp
;; emacs-version: 30.0.50
;; buffer-file-name: "fake-file-name"
;; truncate-lines: t
;; expected-value: t
# |:sec:| local variables test
Here is the output from various Emacs versions, I have access to:
# |:sec:| local variables test
.. code-block:: elisp
;; emacs-version: 22.1.1
;; buffer-file-name: nil
;; truncate-lines: t
;; expected-value: t
.. code-block:: elisp
;; emacs-version: 22.1.1
;; buffer-file-name: "fake-file-name"
;; truncate-lines: t
;; expected-value: t
# |:sec:| local variables test
# |:sec:| local variables test
.. code-block:: elisp
;; emacs-version: 24.3.1
;; buffer-file-name: nil
;; truncate-lines: t
;; expected-value: t
.. code-block:: elisp
;; emacs-version: 24.3.1
;; buffer-file-name: "fake-file-name"
;; truncate-lines: t
;; expected-value: t
# |:sec:| local variables test
# |:sec:| local variables test
.. code-block:: elisp
;; emacs-version: 24.5.1
;; buffer-file-name: nil
;; truncate-lines: t
;; expected-value: t
.. code-block:: elisp
;; emacs-version: 24.5.1
;; buffer-file-name: "fake-file-name"
;; truncate-lines: t
;; expected-value: t
# |:sec:| local variables test
# |:sec:| local variables test
.. code-block:: elisp
;; emacs-version: 25.2.2
;; buffer-file-name: nil
;; truncate-lines: t
;; expected-value: t
.. code-block:: elisp
;; emacs-version: 25.2.2
;; buffer-file-name: "fake-file-name"
;; truncate-lines: t
;; expected-value: t
# |:sec:| local variables test
# |:sec:| local variables test
.. code-block:: elisp
;; emacs-version: 26.3
;; buffer-file-name: nil
;; truncate-lines: t
;; expected-value: nil
.. code-block:: elisp
;; emacs-version: 26.3
;; buffer-file-name: "fake-file-name"
;; truncate-lines: t
;; expected-value: t
# |:sec:| local variables test
# |:sec:| local variables test
.. code-block:: elisp
;; emacs-version: 27.1
;; buffer-file-name: nil
;; truncate-lines: t
;; expected-value: nil
.. code-block:: elisp
;; emacs-version: 27.1
;; buffer-file-name: "fake-file-name"
;; truncate-lines: t
;; expected-value: t
# |:sec:| local variables test
In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
3.24.33, cairo version 1.16.0) of 2023-03-02 built on franke
Repository revision: 828c49ae29fd318547d7bbe4e7fdc65da316e309
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Ubuntu 22.04.1 LTS
Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY
INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS WEBP X11 XDBE XIM XINPUT2 XPM GTK3 ZLIB
Important settings:
value of $LANG: de_DE.UTF-8
locale-coding-system: utf-8-unix
Major mode: Messages
Minor modes in effect:
tooltip-mode: t
global-eldoc-mode: t
show-paren-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
buffer-read-only: t
line-number-mode: t
indent-tabs-mode: t
transient-mark-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
Load-path shadows:
None found.
Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils help-mode novice
display-line-numbers time-date subr-x cl-loaddefs cl-lib rmc iso-transl
tooltip cconv eldoc paren electric uniquify ediff-hook vc-hooks
lisp-float-type elisp-mode 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 lisp-mode prog-mode register page tab-bar menu-bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer nadvice seq
simple cl-generic indonesian philippine 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 emoji-zwj charscript charprop case-table
epa-hook jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button
loaddefs theme-loaddefs faces cus-face macroexp files window
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget keymap hashtable-print-readable backquote threads dbusbind
inotify lcms2 dynamic-setting system-font-setting font-render-setting
cairo move-toolbar gtk x-toolkit xinput2 x multi-tty
make-network-process emacs)
Memory information:
((conses 16 50622 7192)
(symbols 48 6822 0)
(strings 32 16418 2244)
(string-bytes 1 443040)
(vectors 16 9557)
(vector-slots 8 153161 11625)
(floats 8 39 119)
(intervals 56 747 136)
(buffers 976 13))
Information forwarded
to
bug-gnu-emacs <at> gnu.org:
bug#61925; Package
emacs.
(Sat, 04 Mar 2023 10:20:02 GMT)
Full text and
rfc822 format available.
Message #8 received at 61925 <at> debbugs.gnu.org (full text, mbox):
tags 61925 notabug
thanks
> Date: Fri, 3 Mar 2023 00:11:13 +0100
> From: Wolfgang Scherer <Wolfgang.Scherer <at> gmx.de>
>
> The command `normal-mode' does not set file local variables, if a
> buffer does not have a `buffer-file-name'. This affects *scratch* and
> buffers created using `with-temp-buffer'.
>
> The behavior changed at some time between Emacs version 20.5.2.2 and 20.6.3.
> See output from various Emacs versions further below.
>
> If that was an intentional change, it should be prominently documented
> to avoid the confusion when examples do not work in a *scratch* buffer.
This was an intentional change, yes.
And AFAICT, it _is_ documented in the ELisp Reference manual:
-- Command: normal-mode &optional find-file
This function establishes the proper major mode and buffer-local
variable bindings for the current buffer. It calls ‘set-auto-mode’
(see below). As of Emacs 26.1, it no longer runs
‘hack-local-variables’, this now being done in ‘run-mode-hooks’ at
the initialization of major modes (*note Mode Hooks::).
And the documentation of run-mode-hooks says:
-- Function: run-mode-hooks &rest hookvars
Major modes should run their mode hook using this function. It is
similar to ‘run-hooks’ (*note Hooks::), but it also runs
‘change-major-mode-after-body-hook’, ‘hack-local-variables’ (when
the buffer is visiting a file) (*note File Local Variables::) ^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The user manual indeed didn't mention this caveat; I've now mentioned
that aspect there (and also in the doc strings of the relevant
functions).
(The change in Emacs 26 that caused this as a side effect was to fix
bug#15577 and bug#23407.)
> I would even recommend a warning prompt in normal-mode, when called
> interactively.
I think such a warning could be an annoyance.
Added tag(s) notabug.
Request was from
Eli Zaretskii <eliz <at> gnu.org>
to
control <at> debbugs.gnu.org.
(Sat, 04 Mar 2023 10:20:02 GMT)
Full text and
rfc822 format available.
Information forwarded
to
bug-gnu-emacs <at> gnu.org:
bug#61925; Package
emacs.
(Sun, 05 Mar 2023 04:59:02 GMT)
Full text and
rfc822 format available.
Message #13 received at 61925 <at> debbugs.gnu.org (full text, mbox):
> tags 61925 notabug
> thanks
>
>> Date: Fri, 3 Mar 2023 00:11:13 +0100
>> From: Wolfgang Scherer <Wolfgang.Scherer <at> gmx.de>
>>
>> The command `normal-mode' does not set file local variables, if a
>> buffer does not have a `buffer-file-name'. This affects *scratch* and
>> buffers created using `with-temp-buffer'.
>>
>> The behavior changed at some time between Emacs version 20.5.2.2 and 20.6.3.
>> See output from various Emacs versions further below.
>>
>> If that was an intentional change, it should be prominently documented
>> to avoid the confusion when examples do not work in a *scratch* buffer.
> This was an intentional change, yes.
Alright, in this case, I would like to publish an advice which restores
the previous behavior for anybody running into the same problem:
(let* ((expected-value (not (default-value 'truncate-lines)))
(need-advice (with-temp-buffer
(insert (format (concat ";; -*-"
" mode: fudamental-mode;"
" truncate-lines: %S;"
" -*-")
expected-value))
(normal-mode)
(not (eq truncate-lines expected-value)))))
(when need-advice
(defadvice normal-mode (around wsx-normal-mode activate)
"Bind buffer-file-name to `null-device', if it is nil."
(let ((buffer-file-name (or buffer-file-name null-device "/dev/null")))
ad-do-it))))
> And AFAICT, it _is_ documented in the ELisp Reference manual:
>
> -- Command: normal-mode &optional find-file
> This function establishes the proper major mode and buffer-local
> variable bindings for the current buffer. It calls ‘set-auto-mode’
> (see below). As of Emacs 26.1, it no longer runs
> ‘hack-local-variables’, this now being done in ‘run-mode-hooks’ at
> the initialization of major modes (*note Mode Hooks::).
>
> And the documentation of run-mode-hooks says:
>
>
> -- Function: run-mode-hooks &rest hookvars
> Major modes should run their mode hook using this function. It is
> similar to ‘run-hooks’ (*note Hooks::), but it also runs
> ‘change-major-mode-after-body-hook’, ‘hack-local-variables’ (when
> the buffer is visiting a file) (*note File Local Variables::) ^^^^
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> The user manual indeed didn't mention this caveat; I've now mentioned
> that aspect there (and also in the doc strings of the relevant
> functions).
>
> (The change in Emacs 26 that caused this as a side effect was to fix
> bug#15577 and bug#23407.)
>
>> I would even recommend a warning prompt in normal-mode, when called
>> interactively.
> I think such a warning could be an annoyance.
It most definitely should be, to get the proper attention. It
could be disabled by setting a customized variable, pretty much
the same way as risky local variables can be enabled with custom
settings. That would reduce the annoyance to once in a session or
once in a lifetime.
Information forwarded
to
bug-gnu-emacs <at> gnu.org:
bug#61925; Package
emacs.
(Sun, 05 Mar 2023 05:05:01 GMT)
Full text and
rfc822 format available.
Message #16 received at 61925 <at> debbugs.gnu.org (full text, mbox):
> And AFAICT, it _is_ documented in the ELisp Reference manual:
>
> -- Command: normal-mode &optional find-file
> This function establishes the proper major mode and buffer-local
> variable bindings for the current buffer. It calls ‘set-auto-mode’
> (see below). As of Emacs 26.1, it no longer runs
> ‘hack-local-variables’, this now being done in ‘run-mode-hooks’ at
> the initialization of major modes (*note Mode Hooks::).
>
> And the documentation of run-mode-hooks says:
>
>
> -- Function: run-mode-hooks &rest hookvars
> Major modes should run their mode hook using this function. It is
> similar to ‘run-hooks’ (*note Hooks::), but it also runs
> ‘change-major-mode-after-body-hook’, ‘hack-local-variables’ (when
> the buffer is visiting a file) (*note File Local Variables::) ^^^^
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Just for your information, the machinery in `normal-mode' and
`run-mode-hooks' is -- at least in some edge cases -- out of
sync.
Here is a case, where normal-mode in Emacs > 26.1 still calls
`hack-local-variables', which causes a discrepancy, depending on
`delay-mode-hooks', when `after-change-major-mode-hook' alters
the value of a local variable, which is also set in the local
variables list. The reason is, that in `normal-mode'
`after-change-major-mode-hook' is not called the same way as it
is in `run-mode-hooks'.
;; for all cases: `after-change-major-mode-hook' establishes local
;; variable and sets the value to "hello"
;; case 1: buffer with `buffer-file-name' == nil, `delay-mode-hooks' case 1.1: nil, case 1.2: t
(check-normal-mode-in-temp-buffer nil nil nil t ) ::go:: ;; => hello
(check-normal-mode-in-temp-buffer t nil nil t ) ::go:: ;; => good-bye
;; case 2: buffer with `buffer-file-name' not nil, `delay-mode-hooks' case 2.1: nil, case 2.2: t
(check-normal-mode-in-temp-buffer nil t nil t ) ::go:: ;; => hello
(check-normal-mode-in-temp-buffer t t nil t ) ::go:: ;; => good-bye
The following is the complete test setup that I used for testing:
(defun check-normal-mode (&optional set-delay-mode-hooks set-buffer-file-name find-file)
(interactive)
(let ((buffer-file-name (or buffer-file-name (and set-buffer-file-name (or null-device "/dev/null"))))
(delay-mode-hooks (if set-delay-mode-hooks t)))
(normal-mode find-file)))
(defun check-normal-mode-in-temp-buffer (set-delay-mode-hooks set-buffer-file-name change-hook after-hook)
(let ((hook-function #'(lambda () (make-local-variable 'wsx-here-i-am) (setq wsx-here-i-am "hello"))))
(if change-hook
(add-hook 'change-major-mode-after-body-hook hook-function)
(remove-hook 'change-major-mode-after-body-hook hook-function))
(if after-hook
(add-hook 'after-change-major-mode-hook hook-function)
(remove-hook 'after-change-major-mode-hook hook-function))
(put 'wsx-here-i-am 'safe-local-variable 'string-or-null-p)
(with-temp-buffer
(insert ";; -*- mode: lisp-interaction; truncate-lines: t; wsx-here-i-am: \"good bye\"; -*-\n")
(normal-mode)
(check-normal-mode set-delay-mode-hooks set-buffer-file-name)
(describe-variable 'wsx-here-i-am)
)
(remove-hook 'change-major-mode-after-body-hook hook-function)
(remove-hook 'after-change-major-mode-hook hook-function)
(put 'wsx-here-i-am 'safe-local-variable nil)))
;; Emacs >= 26.1
(check-normal-mode-in-temp-buffer nil nil nil nil) ::go:: ;; => void
(check-normal-mode-in-temp-buffer t nil nil nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil t nil nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer t t nil nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil nil t nil) ::go:: ;; => hello
(check-normal-mode-in-temp-buffer t nil t nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil t t nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer t t t nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil nil nil t ) ::go:: ;; => hello
(check-normal-mode-in-temp-buffer t nil nil t ) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil t nil t ) ::go:: ;; => hello
(check-normal-mode-in-temp-buffer t t nil t ) ::go:: ;; => good-bye
;; Emacs < 26.1
(check-normal-mode-in-temp-buffer nil nil nil nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer t nil nil nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil t nil nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer t t nil nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil nil t nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer t nil t nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil t t nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer t t t nil) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil nil nil t ) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer t nil nil t ) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer nil t nil t ) ::go:: ;; => good-bye
(check-normal-mode-in-temp-buffer t t nil t ) ::go:: ;; => good-bye
Information forwarded
to
bug-gnu-emacs <at> gnu.org:
bug#61925; Package
emacs.
(Mon, 06 Mar 2023 02:09:01 GMT)
Full text and
rfc822 format available.
Message #19 received at 61925 <at> debbugs.gnu.org (full text, mbox):
The corrected version of the advice fixes the invalid mode specification.
(let* ((expected-value (not (default-value 'truncate-lines)))
(need-advice (with-temp-buffer
(insert (format (concat ";; -*-"
" mode: fundamental;"
" truncate-lines: %S;"
" -*-")
expected-value))
(normal-mode)
(not (eq truncate-lines expected-value)))))
(when need-advice
(defadvice normal-mode (around wsx-normal-mode activate)
"Bind buffer-file-name to `null-device', if it is nil."
(let ((buffer-file-name (or buffer-file-name null-device "/dev/null")))
ad-do-it))))
Reply sent
to
Stefan Kangas <stefankangas <at> gmail.com>:
You have taken responsibility.
(Wed, 10 Jan 2024 11:09:02 GMT)
Full text and
rfc822 format available.
Notification sent
to
Wolfgang Scherer <Wolfgang.Scherer <at> gmx.de>:
bug acknowledged by developer.
(Wed, 10 Jan 2024 11:09:02 GMT)
Full text and
rfc822 format available.
Message #24 received at 61925-done <at> debbugs.gnu.org (full text, mbox):
Eli Zaretskii <eliz <at> gnu.org> writes:
> tags 61925 notabug
> thanks
>
>> Date: Fri, 3 Mar 2023 00:11:13 +0100
>> From: Wolfgang Scherer <Wolfgang.Scherer <at> gmx.de>
>>
>> The command `normal-mode' does not set file local variables, if a
>> buffer does not have a `buffer-file-name'. This affects *scratch* and
>> buffers created using `with-temp-buffer'.
>>
>> The behavior changed at some time between Emacs version 20.5.2.2 and 20.6.3.
>> See output from various Emacs versions further below.
>>
>> If that was an intentional change, it should be prominently documented
>> to avoid the confusion when examples do not work in a *scratch* buffer.
>
> This was an intentional change, yes.
>
> And AFAICT, it _is_ documented in the ELisp Reference manual:
>
> -- Command: normal-mode &optional find-file
> This function establishes the proper major mode and buffer-local
> variable bindings for the current buffer. It calls ‘set-auto-mode’
> (see below). As of Emacs 26.1, it no longer runs
> ‘hack-local-variables’, this now being done in ‘run-mode-hooks’ at
> the initialization of major modes (*note Mode Hooks::).
>
> And the documentation of run-mode-hooks says:
>
>
> -- Function: run-mode-hooks &rest hookvars
> Major modes should run their mode hook using this function. It is
> similar to ‘run-hooks’ (*note Hooks::), but it also runs
> ‘change-major-mode-after-body-hook’, ‘hack-local-variables’ (when
> the buffer is visiting a file) (*note File Local Variables::) ^^^^
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> The user manual indeed didn't mention this caveat; I've now mentioned
> that aspect there (and also in the doc strings of the relevant
> functions).
>
> (The change in Emacs 26 that caused this as a side effect was to fix
> bug#15577 and bug#23407.)
>
>> I would even recommend a warning prompt in normal-mode, when called
>> interactively.
>
> I think such a warning could be an annoyance.
It seems like we're not going to be making any changes here, as this is
the expected behavior.
I'm therefore closing this bug report.
bug archived.
Request was from
Debbugs Internal Request <help-debbugs <at> gnu.org>
to
internal_control <at> debbugs.gnu.org.
(Wed, 07 Feb 2024 12:24:08 GMT)
Full text and
rfc822 format available.
This bug report was last modified 1 year and 92 days ago.
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