bug#25478: 26.0.50; No hooks are called when auto-saving

bug#25478: 26.0.50; No hooks are called when auto-saving

[Philipp Stephani]

The Emacs manual states:

"If you want auto-saving to be done in the visited file rather than in
a separate auto-save file, set the variable
‘auto-save-visited-file-name’ to a non-‘nil’ value.  In this mode, there
is no real difference between auto-saving and explicit saving."

However, there is a significant difference between auto-saving and
explicit saving, even in this mode: auto-saving doesn't run
before-save-hook, after-save-hook, write-contents-functions, or
write-file-functions.  Either some of these hooks should be run during
auto-saving if auto-save-visited-file-name is t, or new hooks should be
created to run in this case.


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bug#25478: 26.0.50; No hooks are called when auto-saving

[Glenn Morris]

Philipp Stephani wrote:

> The Emacs manual states:
>
> "If you want auto-saving to be done in the visited file rather than in
> a separate auto-save file, set the variable
> 'auto-save-visited-file-name' to a non-'nil' value.  In this mode, there
> is no real difference between auto-saving and explicit saving."
>
> However, there is a significant difference between auto-saving and
> explicit saving, even in this mode: auto-saving doesn't run
> before-save-hook, after-save-hook, write-contents-functions, or
> write-file-functions.  Either some of these hooks should be run during
> auto-saving if auto-save-visited-file-name is t, or new hooks should be
> created to run in this case.


The phrasing of the manual can easily be changed if it's creating
unreasonable expectations.
Do you have a use case for autosave running hooks?
One could argue that it is a low-level
operation that should not be modifiable in this way.

bug#25478: 26.0.50; No hooks are called when auto-saving

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Date: Thu, 19 Jan 2017 15:29:04 -0500
> Cc: 25478@debbugs.gnu.org
> 
> Philipp Stephani wrote:
> 
> > The Emacs manual states:
> >
> > "If you want auto-saving to be done in the visited file rather than in
> > a separate auto-save file, set the variable
> > 'auto-save-visited-file-name' to a non-'nil' value.  In this mode, there
> > is no real difference between auto-saving and explicit saving."
> >
> > However, there is a significant difference between auto-saving and
> > explicit saving, even in this mode: auto-saving doesn't run
> > before-save-hook, after-save-hook, write-contents-functions, or
> > write-file-functions.  Either some of these hooks should be run during
> > auto-saving if auto-save-visited-file-name is t, or new hooks should be
> > created to run in this case.
> 
> The phrasing of the manual can easily be changed if it's creating
> unreasonable expectations.

I've done that now on the release branch.

> Do you have a use case for autosave running hooks?
> One could argue that it is a low-level
> operation that should not be modifiable in this way.

Auto-save has its own hook.  But that's just the tip of an iceberg,
because nowadays various modes can completely change what happens at
save-buffer time by using the hooks mentioned above, and those hooks
run only when basic-save-buffer is invoked; they won't be run during
auto-saving.

And there are other differences, too.  E.g., if save-buffer asks the
user for a suitable encoding, it will record the value used in
buffer-file-coding-system, so that future saves reuse that
automatically.  Auto-saving doesn't record the value, so if the user
doesn't change the buffer's file encoding manually, she will be
prompted to provide an encoding on every auto-save.

All in all, I think this option is subtly dangerous and should be
either deprecated or completely reimplemented to invoke
basic-save-buffer instead.  I'm quite sure this option made sense in
the past, when complications with encoding and save-related hooks
didn't exist, but that is no longer the case in Emacs these days.
If someone thinks using this option will allow them not to bother with
saving their edits, they are in for an unpleasant surprise.

(Not sure whether we should close this bug now that the documentation
is fixed.)

bug#25478: 26.0.50; No hooks are called when auto-saving

[Glenn Morris]

Eli Zaretskii wrote:

> All in all, I think this option is subtly dangerous and should be
> either deprecated or completely reimplemented to invoke
> basic-save-buffer instead.  I'm quite sure this option made sense in
> the past, when complications with encoding and save-related hooks
> didn't exist, but that is no longer the case in Emacs these days.
> If someone thinks using this option will allow them not to bother with
> saving their edits, they are in for an unpleasant surprise.

Deprecation sounds good to me.
I believe there's a "real-auto-save" package that does a standard save
at intervals.

bug#25478: 26.0.50; No hooks are called when auto-saving

[Philipp Stephani]

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Eli Zaretskii <eliz@gnu.org> schrieb am Fr., 20. Jan. 2017 um 09:45 Uhr:

> > From: Glenn Morris <rgm@gnu.org>
> > Date: Thu, 19 Jan 2017 15:29:04 -0500
> > Cc: 25478@debbugs.gnu.org
> >
> > Philipp Stephani wrote:
> >
> > > The Emacs manual states:
> > >
> > > "If you want auto-saving to be done in the visited file rather than in
> > > a separate auto-save file, set the variable
> > > 'auto-save-visited-file-name' to a non-'nil' value.  In this mode,
> there
> > > is no real difference between auto-saving and explicit saving."
> > >
> > > However, there is a significant difference between auto-saving and
> > > explicit saving, even in this mode: auto-saving doesn't run
> > > before-save-hook, after-save-hook, write-contents-functions, or
> > > write-file-functions.  Either some of these hooks should be run during
> > > auto-saving if auto-save-visited-file-name is t, or new hooks should be
> > > created to run in this case.
> >
> > The phrasing of the manual can easily be changed if it's creating
> > unreasonable expectations.
>
> I've done that now on the release branch.
>
> > Do you have a use case for autosave running hooks?
> > One could argue that it is a low-level
> > operation that should not be modifiable in this way.
>
> Auto-save has its own hook.  But that's just the tip of an iceberg,
> because nowadays various modes can completely change what happens at
> save-buffer time by using the hooks mentioned above, and those hooks
> run only when basic-save-buffer is invoked; they won't be run during
> auto-saving.
>
> And there are other differences, too.  E.g., if save-buffer asks the
> user for a suitable encoding, it will record the value used in
> buffer-file-coding-system, so that future saves reuse that
> automatically.  Auto-saving doesn't record the value, so if the user
> doesn't change the buffer's file encoding manually, she will be
> prompted to provide an encoding on every auto-save.
>
> All in all, I think this option is subtly dangerous and should be
> either deprecated or completely reimplemented to invoke
> basic-save-buffer instead.  I'm quite sure this option made sense in
> the past, when complications with encoding and save-related hooks
> didn't exist, but that is no longer the case in Emacs these days.
> If someone thinks using this option will allow them not to bother with
> saving their edits, they are in for an unpleasant surprise.
>
>
That's quite unfortunate, as not having to bother with saving edits
manually is a very desirable feature that I think Emacs should offer out of
the box.

If you really want to deprecate auto-save-visited-file-name, how about
adding a simple global minor mode that invokes save-some-buffers from an
idle timer to files.el?

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bug#25478: 26.0.50; No hooks are called when auto-saving

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Sun, 26 Mar 2017 18:21:01 +0000
> Cc: 25478@debbugs.gnu.org
> 
>  All in all, I think this option is subtly dangerous and should be
>  either deprecated or completely reimplemented to invoke
>  basic-save-buffer instead. I'm quite sure this option made sense in
>  the past, when complications with encoding and save-related hooks
>  didn't exist, but that is no longer the case in Emacs these days.
>  If someone thinks using this option will allow them not to bother with
>  saving their edits, they are in for an unpleasant surprise.
> 
> That's quite unfortunate, as not having to bother with saving edits manually is a very desirable feature that I
> think Emacs should offer out of the box.
> 
> If you really want to deprecate auto-save-visited-file-name, how about adding a simple global minor mode that
> invokes save-some-buffers from an idle timer to files.el? 

As I wrote, I'm also okay with Someone™ volunteering to reimplement
this option such that it invokes basic-save-buffer instead.

A minor mode that you describe would also be fine, but then it should
probably disable auto-saving if auto-save-visited-file-name is set,
right?

bug#25478: 26.0.50; No hooks are called when auto-saving

[Philipp Stephani]

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Eli Zaretskii <eliz@gnu.org> schrieb am So., 26. März 2017 um 20:46 Uhr:

> > From: Philipp Stephani <p.stephani2@gmail.com>
> > Date: Sun, 26 Mar 2017 18:21:01 +0000
> > Cc: 25478@debbugs.gnu.org
> >
> >  All in all, I think this option is subtly dangerous and should be
> >  either deprecated or completely reimplemented to invoke
> >  basic-save-buffer instead. I'm quite sure this option made sense in
> >  the past, when complications with encoding and save-related hooks
> >  didn't exist, but that is no longer the case in Emacs these days.
> >  If someone thinks using this option will allow them not to bother with
> >  saving their edits, they are in for an unpleasant surprise.
> >
> > That's quite unfortunate, as not having to bother with saving edits
> manually is a very desirable feature that I
> > think Emacs should offer out of the box.
> >
> > If you really want to deprecate auto-save-visited-file-name, how about
> adding a simple global minor mode that
> > invokes save-some-buffers from an idle timer to files.el?
>
> As I wrote, I'm also okay with Someone™ volunteering to reimplement
> this option such that it invokes basic-save-buffer instead.
>
> A minor mode that you describe would also be fine, but then it should
> probably disable auto-saving if auto-save-visited-file-name is set,
> right?
>

Sounds reasonable. I'll try to come up with something by next weekend.
Probably it will be just

(defvar auto-save--timer nil)
(defcustom auto-save-visited-interval 5
  "seconds"
  :group 'files
  :type 'number
  :set (lambda (symbol value)
         (set-default symbol value)
         (when auto-save--timer
           (timer-set-idle-time auto-save--timer value :repeat))))
(define-minor-mode auto-save-visited-mode nil
  :group 'files
  :global t
  (when auto-save--timer (kill-timer auto-save--timer))
  (setq auto-save--timer
        (when auto-save-visited-mode
          (run-with-idle-timer
           auto-save-visited-interval :repeat
           #'save-some-buffers :no-prompt
           (lambda ()
             (not (and buffer-auto-save-file-name
auto-save-visited-file-name)))))))

but it will also need tests and documentation, which take a bit more time.

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bug#25478: 26.0.50; No hooks are called when auto-saving

[Philipp Stephani]

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Philipp Stephani <p.stephani2@gmail.com> schrieb am So., 26. März 2017 um
21:17 Uhr:

> Eli Zaretskii <eliz@gnu.org> schrieb am So., 26. März 2017 um 20:46 Uhr:
>
>> > From: Philipp Stephani <p.stephani2@gmail.com>
>> > Date: Sun, 26 Mar 2017 18:21:01 +0000
>> > Cc: 25478@debbugs.gnu.org
>> >
>> >  All in all, I think this option is subtly dangerous and should be
>> >  either deprecated or completely reimplemented to invoke
>> >  basic-save-buffer instead. I'm quite sure this option made sense in
>> >  the past, when complications with encoding and save-related hooks
>> >  didn't exist, but that is no longer the case in Emacs these days.
>> >  If someone thinks using this option will allow them not to bother with
>> >  saving their edits, they are in for an unpleasant surprise.
>> >
>> > That's quite unfortunate, as not having to bother with saving edits
>> manually is a very desirable feature that I
>> > think Emacs should offer out of the box.
>> >
>> > If you really want to deprecate auto-save-visited-file-name, how about
>> adding a simple global minor mode that
>> > invokes save-some-buffers from an idle timer to files.el?
>>
>> As I wrote, I'm also okay with Someone™ volunteering to reimplement
>> this option such that it invokes basic-save-buffer instead.
>>
>> A minor mode that you describe would also be fine, but then it should
>> probably disable auto-saving if auto-save-visited-file-name is set,
>> right?
>>
>
> Sounds reasonable. I'll try to come up with something by next weekend.
> Probably it will be just
>
> (defvar auto-save--timer nil)
> (defcustom auto-save-visited-interval 5
>   "seconds"
>   :group 'files
>   :type 'number
>   :set (lambda (symbol value)
>          (set-default symbol value)
>          (when auto-save--timer
>            (timer-set-idle-time auto-save--timer value :repeat))))
> (define-minor-mode auto-save-visited-mode nil
>   :group 'files
>   :global t
>   (when auto-save--timer (kill-timer auto-save--timer))
>   (setq auto-save--timer
>         (when auto-save-visited-mode
>           (run-with-idle-timer
>            auto-save-visited-interval :repeat
>            #'save-some-buffers :no-prompt
>            (lambda ()
>              (not (and buffer-auto-save-file-name
> auto-save-visited-file-name)))))))
>
> but it will also need tests and documentation, which take a bit more time.
>

Here's a patch.

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From 2a14636a0610d1bc6e024a56b788a575c039f784 Mon Sep 17 00:00:00 2001
From: Philipp Stephani <phst@google.com>
Date: Sat, 22 Apr 2017 20:58:38 +0200
Subject: [PATCH] Reimplement auto-saving to visited files

This reacts to confusing behavior of 'auto-save-visited-file-name',
cf. Bug#25478.

* lisp/files.el (auto-save-visited-interval): New customization option.
(auto-save-visited-mode): New global minor mode.
(auto-save-visited-file-name): Make obsolete.
(auto-save--timer): New internal helper variable.

* doc/emacs/files.texi (Auto Save Files): Document
'auto-save-visited-mode' instead of obsolete
'auto-save-visited-file-name'.
(Auto Save Control): Document customization option
'auto-save-visited-interval'.
---
 doc/emacs/files.texi | 20 +++++++++++++-------
 etc/NEWS             |  6 ++++++
 lisp/files.el        | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/doc/emacs/files.texi b/doc/emacs/files.texi
index ed17f66ca2..08c8beed96 100644
--- a/doc/emacs/files.texi
+++ b/doc/emacs/files.texi
@@ -1040,14 +1040,13 @@ Auto Save Files
 this happens, save the buffer with @kbd{C-x C-s}, or use @kbd{C-u 1 M-x
 auto-save-mode}.
 
-@vindex auto-save-visited-file-name
+@vindex auto-save-visited-mode
   If you want auto-saving to be done in the visited file rather than
-in a separate auto-save file, set the variable
-@code{auto-save-visited-file-name} to a non-@code{nil} value.  In this
-mode, auto-saving is very similar to explicit saving.  However,
-differences still exist, in particular for modes which modify the
-buffer-saving process in non-trivial ways via various hooks
-(@pxref{Saving Buffers,,, elisp, The Emacs Lisp Reference Manual}).
+in a separate auto-save file, enable the global minor mode
+@code{auto-save-visited-mode}.  In this mode, auto-saving is very
+similar to explicit saving.  Note that this mode is orthogonal to the
+@code{auto-save} mode described above; you can enable both at the same
+time.
 
 @vindex delete-auto-save-files
   A buffer's auto-save file is deleted when you save the buffer in its
@@ -1091,6 +1090,13 @@ Auto Save Control
 a while; second, it may avoid some auto-saving while you are actually
 typing.
 
+@vindex auto-save-visited-interval
+  When @code{auto-save-visited-mode} is enabled, Emacs will auto-save
+file-visiting buffers after five seconds of idle time.  You can
+customize the variable @code{auto-save-visited-interval} to change the
+idle time interval.  @code{auto-save-interval} and
+@code{auto-save-timeout} have no effect on this mode.
+
   Emacs also does auto-saving whenever it gets a fatal error.  This
 includes killing the Emacs job with a shell command such as @samp{kill
 %emacs}, or disconnecting a phone line or network connection.
diff --git a/etc/NEWS b/etc/NEWS
index 7281827878..2f10276d12 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -383,6 +383,12 @@ Strings such as ΌΣΟΣ are now correctly converted to Όσος when
 capitalized instead of incorrect Όσοσ (compare lowercase sigma at the
 end of the word).
 
+** Emacs can now auto-save buffers to visited files in a more robust
+manner via the new mode 'auto-save-visited-mode'.  Unlike
+'auto-save-visited-file-name', this mode uses the normal saving
+procedure and therefore obeys saving hooks.
+'auto-save-visited-file-name' is now obsolete.
+
 \f
 * Changes in Specialized Modes and Packages in Emacs 26.1
 
diff --git a/lisp/files.el b/lisp/files.el
index 6848818cad..cf9037ec68 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -393,6 +393,45 @@ auto-save-file-name-transforms
   :initialize 'custom-initialize-delay
   :version "21.1")
 
+(defvar auto-save--timer nil "Timer for `auto-save-visited-mode'.")
+
+(defcustom auto-save-visited-interval 5
+  "Interval in seconds for `auto-save-visited-mode'.
+If `auto-save-visited-mode' is enabled, Emacs will save all
+buffers visiting a file to the visited file after it has been
+idle for `auto-save-visited-interval' seconds."
+  :group 'auto-save
+  :type 'number
+  :set (lambda (symbol value)
+         (set-default symbol value)
+         (when auto-save--timer
+           (timer-set-idle-time auto-save--timer value :repeat))))
+
+(define-minor-mode auto-save-visited-mode
+  "Toggle automatic saving to file-visiting buffers on or off.
+With a prefix argument ARG, enable regular saving of all buffers
+vising a file if ARG is positive, and disable it otherwise.
+Unlike `auto-save-mode', this mode will auto-save buffer contents
+to the visited files directly and will also run all save-related
+hooks.  See Info node `Saving' for details of the save process.
+
+If called from Lisp, enable the mode if ARG is omitted or nil,
+and toggle it if ARG is `toggle'."
+  :group 'auto-save
+  :global t
+  (when auto-save--timer (kill-timer auto-save--timer))
+  (setq auto-save--timer
+        (when auto-save-visited-mode
+          (run-with-idle-timer
+           auto-save-visited-interval :repeat
+           #'save-some-buffers :no-prompt
+           (lambda ()
+             (not (and buffer-auto-save-file-name
+                       auto-save-visited-file-name)))))))
+
+(make-obsolete-variable 'auto-save-visited-file-name 'auto-save-visited-mode
+                        "Emacs 26.1")
+
 (defcustom save-abbrevs t
   "Non-nil means save word abbrevs too when files are saved.
 If `silently', don't ask the user before saving."
-- 
2.12.2

bug#25478: 26.0.50; No hooks are called when auto-saving

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Sat, 22 Apr 2017 19:01:50 +0000
> Cc: rgm@gnu.org, 25478@debbugs.gnu.org
> 
> Here's a patch. 

Thanks.  A few minor comments:

> --- a/doc/emacs/files.texi
> +++ b/doc/emacs/files.texi
> @@ -1040,14 +1040,13 @@ Auto Save Files
>  this happens, save the buffer with @kbd{C-x C-s}, or use @kbd{C-u 1 M-x
>  auto-save-mode}.
>  
> -@vindex auto-save-visited-file-name
> +@vindex auto-save-visited-mode

I wonder whether auto-save-files-mode is a better name, as the
"visited" part looks now out of place.  (If you do rename it, please
also rename the time-interval variable accordingly.)

> +in a separate auto-save file, enable the global minor mode
> +@code{auto-save-visited-mode}.  In this mode, auto-saving is very
> +similar to explicit saving.

"Very similar" begs the question "what's the difference?"  If there
are differences, let's describe them; if there aren't, let's say
"identical to" or "the same as".

>                                Note that this mode is orthogonal to the
> +@code{auto-save} mode described above; you can enable both at the same
> +time.

But if auto-save mode is enabled and auto-save-visited-file-name is
set, then this new mode will not auto-save, right?  This should be
documented.

> @@ -1091,6 +1090,13 @@ Auto Save Control
>  a while; second, it may avoid some auto-saving while you are actually
>  typing.
>  
> +@vindex auto-save-visited-interval

I suggest to mention this variable where you describe the new mode,
since the two descriptions are several tens of lines apart.

> +  When @code{auto-save-visited-mode} is enabled, Emacs will auto-save
> +file-visiting buffers after five seconds of idle time.  You can
> +customize the variable @code{auto-save-visited-interval} to change the
> +idle time interval.  @code{auto-save-interval} and
> +@code{auto-save-timeout} have no effect on this mode.

I think the last sentence should be part of the description of the
mode, not of the variable.  Doing so will also provide a good
opportunity to mention auto-save-visited-interval.

> +(defcustom auto-save-visited-interval 5
> +  "Interval in seconds for `auto-save-visited-mode'.
> +If `auto-save-visited-mode' is enabled, Emacs will save all
> +buffers visiting a file to the visited file after it has been
> +idle for `auto-save-visited-interval' seconds."
> +  :group 'auto-save
> +  :type 'number
> +  :set (lambda (symbol value)
> +         (set-default symbol value)
> +         (when auto-save--timer
> +           (timer-set-idle-time auto-save--timer value :repeat))))

Please add a :version tag to new defcustoms.

> +(define-minor-mode auto-save-visited-mode
> +  "Toggle automatic saving to file-visiting buffers on or off.
> +With a prefix argument ARG, enable regular saving of all buffers
> +vising a file if ARG is positive, and disable it otherwise.
   ^^^^^^
A typo.

bug#25478: 26.0.50; No hooks are called when auto-saving

[Philipp Stephani]

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Eli Zaretskii <eliz@gnu.org> schrieb am Fr., 28. Apr. 2017 um 11:28 Uhr:

> > From: Philipp Stephani <p.stephani2@gmail.com>
> > Date: Sat, 22 Apr 2017 19:01:50 +0000
> > Cc: rgm@gnu.org, 25478@debbugs.gnu.org
> >
> > Here's a patch.
>
> Thanks.  A few minor comments:
>
> > --- a/doc/emacs/files.texi
> > +++ b/doc/emacs/files.texi
> > @@ -1040,14 +1040,13 @@ Auto Save Files
> >  this happens, save the buffer with @kbd{C-x C-s}, or use @kbd{C-u 1 M-x
> >  auto-save-mode}.
> >
> > -@vindex auto-save-visited-file-name
> > +@vindex auto-save-visited-mode
>
> I wonder whether auto-save-files-mode is a better name, as the
> "visited" part looks now out of place.  (If you do rename it, please
> also rename the time-interval variable accordingly.)
>

I think the name should be sufficiently different from auto-save-mode so
that the modes can't be confused. auto-save-files-mode would be confusing,
because auto-save-mode also saves files. I think including the "visited"
word is useful here because it's the meaningful distinction between the
modes: one uses the visited file name, the other doesn't.


>
> > +in a separate auto-save file, enable the global minor mode
> > +@code{auto-save-visited-mode}.  In this mode, auto-saving is very
> > +similar to explicit saving.
>
> "Very similar" begs the question "what's the difference?"  If there
> are differences, let's describe them; if there aren't, let's say
> "identical to" or "the same as".
>

Done.


>
> >                                Note that this mode is orthogonal to the
> > +@code{auto-save} mode described above; you can enable both at the same
> > +time.
>
> But if auto-save mode is enabled and auto-save-visited-file-name is
> set, then this new mode will not auto-save, right?  This should be
> documented.
>

Done.


>
> > @@ -1091,6 +1090,13 @@ Auto Save Control
> >  a while; second, it may avoid some auto-saving while you are actually
> >  typing.
> >
> > +@vindex auto-save-visited-interval
>
> I suggest to mention this variable where you describe the new mode,
> since the two descriptions are several tens of lines apart.
>

Done.


>
> > +  When @code{auto-save-visited-mode} is enabled, Emacs will auto-save
> > +file-visiting buffers after five seconds of idle time.  You can
> > +customize the variable @code{auto-save-visited-interval} to change the
> > +idle time interval.  @code{auto-save-interval} and
> > +@code{auto-save-timeout} have no effect on this mode.
>
> I think the last sentence should be part of the description of the
> mode, not of the variable.  Doing so will also provide a good
> opportunity to mention auto-save-visited-interval.
>

Done.


>
> > +(defcustom auto-save-visited-interval 5
> > +  "Interval in seconds for `auto-save-visited-mode'.
> > +If `auto-save-visited-mode' is enabled, Emacs will save all
> > +buffers visiting a file to the visited file after it has been
> > +idle for `auto-save-visited-interval' seconds."
> > +  :group 'auto-save
> > +  :type 'number
> > +  :set (lambda (symbol value)
> > +         (set-default symbol value)
> > +         (when auto-save--timer
> > +           (timer-set-idle-time auto-save--timer value :repeat))))
>
> Please add a :version tag to new defcustoms.
>

Done.


>
> > +(define-minor-mode auto-save-visited-mode
> > +  "Toggle automatic saving to file-visiting buffers on or off.
> > +With a prefix argument ARG, enable regular saving of all buffers
> > +vising a file if ARG is positive, and disable it otherwise.
>    ^^^^^^
> A typo.
>

Done.

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bug#25478: [PATCH] Reimplement auto-saving to visited files

[Philipp Stephani]

This reacts to confusing behavior of 'auto-save-visited-file-name',
cf. Bug#25478.

* lisp/files.el (auto-save-visited-interval): New customization option.
(auto-save-visited-mode): New global minor mode.
(auto-save-visited-file-name): Make obsolete.
(auto-save--timer): New internal helper variable.

* doc/emacs/files.texi (Auto Save Files): Document
'auto-save-visited-mode' instead of obsolete
'auto-save-visited-file-name'.
(Auto Save Control): Document customization option
'auto-save-visited-interval'.
---
 doc/emacs/files.texi | 29 ++++++++++++++++++++++-------
 etc/NEWS             |  6 ++++++
 lisp/files.el        | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+), 7 deletions(-)

diff --git a/doc/emacs/files.texi b/doc/emacs/files.texi
index ed17f66ca2..55eda00d0c 100644
--- a/doc/emacs/files.texi
+++ b/doc/emacs/files.texi
@@ -1040,14 +1040,23 @@ Auto Save Files
 this happens, save the buffer with @kbd{C-x C-s}, or use @kbd{C-u 1 M-x
 auto-save-mode}.
 
-@vindex auto-save-visited-file-name
+@vindex auto-save-visited-mode
   If you want auto-saving to be done in the visited file rather than
-in a separate auto-save file, set the variable
-@code{auto-save-visited-file-name} to a non-@code{nil} value.  In this
-mode, auto-saving is very similar to explicit saving.  However,
-differences still exist, in particular for modes which modify the
-buffer-saving process in non-trivial ways via various hooks
-(@pxref{Saving Buffers,,, elisp, The Emacs Lisp Reference Manual}).
+in a separate auto-save file, enable the global minor mode
+@code{auto-save-visited-mode}.  In this mode, auto-saving is identical
+to explicit saving.  Note that this mode is orthogonal to the
+@code{auto-save} mode described above; you can enable both at the same
+time.  However, if @code{auto-save} mode is active in some buffer and
+the obsolete @code{auto-save-visited-file-name} variable is set to a
+non-@code{nil} value, that buffer won't be affected by
+@code{auto-save-visited-mode}.
+
+  You can use the variable @code{auto-save-visited-interval} to
+customize the interval between auto-save operations in
+@code{auto-save-visited-mode}; by default it's five seconds.
+@code{auto-save-interval} and @code{auto-save-timeout} have no effect
+on @code{auto-save-visited-mode}.  See @xref{Auto Save Control} for
+details on these variables.
 
 @vindex delete-auto-save-files
   A buffer's auto-save file is deleted when you save the buffer in its
@@ -1091,6 +1100,12 @@ Auto Save Control
 a while; second, it may avoid some auto-saving while you are actually
 typing.
 
+@vindex auto-save-visited-interval
+  When @code{auto-save-visited-mode} is enabled, Emacs will auto-save
+file-visiting buffers after five seconds of idle time.  You can
+customize the variable @code{auto-save-visited-interval} to change the
+idle time interval.
+
   Emacs also does auto-saving whenever it gets a fatal error.  This
 includes killing the Emacs job with a shell command such as @samp{kill
 %emacs}, or disconnecting a phone line or network connection.
diff --git a/etc/NEWS b/etc/NEWS
index 9d4c72d6dc..173c4e466b 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -383,6 +383,12 @@ Strings such as ΌΣΟΣ are now correctly converted to Όσος when
 capitalized instead of incorrect Όσοσ (compare lowercase sigma at the
 end of the word).
 
+** Emacs can now auto-save buffers to visited files in a more robust
+manner via the new mode 'auto-save-visited-mode'.  Unlike
+'auto-save-visited-file-name', this mode uses the normal saving
+procedure and therefore obeys saving hooks.
+'auto-save-visited-file-name' is now obsolete.
+
 \f
 * Changes in Specialized Modes and Packages in Emacs 26.1
 
diff --git a/lisp/files.el b/lisp/files.el
index 6848818cad..d3958b5643 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -393,6 +393,46 @@ auto-save-file-name-transforms
   :initialize 'custom-initialize-delay
   :version "21.1")
 
+(defvar auto-save--timer nil "Timer for `auto-save-visited-mode'.")
+
+(defcustom auto-save-visited-interval 5
+  "Interval in seconds for `auto-save-visited-mode'.
+If `auto-save-visited-mode' is enabled, Emacs will save all
+buffers visiting a file to the visited file after it has been
+idle for `auto-save-visited-interval' seconds."
+  :group 'auto-save
+  :type 'number
+  :version "26.1"
+  :set (lambda (symbol value)
+         (set-default symbol value)
+         (when auto-save--timer
+           (timer-set-idle-time auto-save--timer value :repeat))))
+
+(define-minor-mode auto-save-visited-mode
+  "Toggle automatic saving to file-visiting buffers on or off.
+With a prefix argument ARG, enable regular saving of all buffers
+visiting a file if ARG is positive, and disable it otherwise.
+Unlike `auto-save-mode', this mode will auto-save buffer contents
+to the visited files directly and will also run all save-related
+hooks.  See Info node `Saving' for details of the save process.
+
+If called from Lisp, enable the mode if ARG is omitted or nil,
+and toggle it if ARG is `toggle'."
+  :group 'auto-save
+  :global t
+  (when auto-save--timer (kill-timer auto-save--timer))
+  (setq auto-save--timer
+        (when auto-save-visited-mode
+          (run-with-idle-timer
+           auto-save-visited-interval :repeat
+           #'save-some-buffers :no-prompt
+           (lambda ()
+             (not (and buffer-auto-save-file-name
+                       auto-save-visited-file-name)))))))
+
+(make-obsolete-variable 'auto-save-visited-file-name 'auto-save-visited-mode
+                        "Emacs 26.1")
+
 (defcustom save-abbrevs t
   "Non-nil means save word abbrevs too when files are saved.
 If `silently', don't ask the user before saving."
-- 
2.12.2

bug#25478: [PATCH] Reimplement auto-saving to visited files

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Cc: Philipp Stephani <phst@google.com>
> Date: Sat, 29 Apr 2017 20:49:09 +0200
> 
> +on @code{auto-save-visited-mode}.  See @xref{Auto Save Control} for

@xref itself produces "See", so the "See" before it is unnecessary.

Other than that, I think this can go in.  Thanks for working on this.

bug#25478: [PATCH] Reimplement auto-saving to visited files

[Philipp Stephani]

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Eli Zaretskii <eliz@gnu.org> schrieb am Sa., 29. Apr. 2017 um 21:21 Uhr:

> > From: Philipp Stephani <p.stephani2@gmail.com>
> > Cc: Philipp Stephani <phst@google.com>
> > Date: Sat, 29 Apr 2017 20:49:09 +0200
> >
> > +on @code{auto-save-visited-mode}.  See @xref{Auto Save Control} for
>
> @xref itself produces "See", so the "See" before it is unnecessary.
>
> Other than that, I think this can go in.  Thanks for working on this.
>

Thanks, pushed as 4db844a453 and 89159e78bb.

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bug#25478: [PATCH] Reimplement auto-saving to visited files

[Stefan Kangas]

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

> Eli Zaretskii <eliz@gnu.org> schrieb am Sa., 29. Apr. 2017 um 21:21 Uhr:
>
>  > From: Philipp Stephani <p.stephani2@gmail.com>
>  > Cc: Philipp Stephani <phst@google.com>
>  > Date: Sat, 29 Apr 2017 20:49:09 +0200
>  >
>  > +on @code{auto-save-visited-mode}.  See @xref{Auto Save Control} for
>
>  @xref itself produces "See", so the "See" before it is unnecessary.
>
>  Other than that, I think this can go in.  Thanks for working on this.
>
> Thanks, pushed as 4db844a453 and 89159e78bb.

It seems like all the patches here were pushed.  Should this therefore
also be closed, or is there more to do here?

Best regards,
Stefan Kangas

bug#25478: [PATCH] Reimplement auto-saving to visited files

[Stefan Kangas]

Stefan Kangas <stefan@marxist.se> writes:

> Philipp Stephani <p.stephani2@gmail.com> writes:
>
>> Eli Zaretskii <eliz@gnu.org> schrieb am Sa., 29. Apr. 2017 um 21:21 Uhr:
>>
>>  > From: Philipp Stephani <p.stephani2@gmail.com>
>>  > Cc: Philipp Stephani <phst@google.com>
>>  > Date: Sat, 29 Apr 2017 20:49:09 +0200
>>  >
>>  > +on @code{auto-save-visited-mode}.  See @xref{Auto Save Control} for
>>
>>  @xref itself produces "See", so the "See" before it is unnecessary.
>>
>>  Other than that, I think this can go in.  Thanks for working on this.
>>
>> Thanks, pushed as 4db844a453 and 89159e78bb.
>
> It seems like all the patches here were pushed.  Should this therefore
> also be closed, or is there more to do here?

More information was requested, but none was given within 7 weeks, so
I'm closing this bug.  If this is still an issue, please reply to this
email (use "Reply to all" in your email client) and we can reopen the
bug report.

Best regards,
Stefan Kangas