global-auto-revert-mode and file time stamps

global-auto-revert-mode and file time stamps

[Timur Aydin]

When a file's timestamp has been changed, but the contents are still the
same, what should be the behavior of emacs be? With the emacs that I am
using (development version):

GNU Emacs 24.3.50.1 (i686-pc-linux-gnu, GTK+ Version 3.6.3)
 of 2013-05-01 on bonsai

It thinks the file is changed. Here is what I do:

- Open a file, edit it and then save.

- use the "touch" command to update the time stamp of this file.

- Wait way more than the auto revert interval (which is set to 5 seconds
in my case).

- Try to make a change to the buffer corresponding to this file.

At this point, emacs says that the file has changed and asks whether I
really want to edit it. I was expecting emacs to auto revert this buffer
and allow me to edit it without further questions. So my question is, am
I looking at a bug, or a feature?

-- 
Timur Aydin

global-auto-revert-mode and file time stamps

[Timur Aydin]

Hi, I have sent this message to help-gnu-emacs, but I thought maybe 
development list is better, because I am using a development version. 
Here it goes:

When a file's timestamp has been changed, but the contents are still the
same, what should be the behavior of emacs be? With the emacs that I am
using (development version):

GNU Emacs 24.3.50.1 (i686-pc-linux-gnu, GTK+ Version 3.6.3)
  of 2013-05-01 on bonsai

It thinks the file is changed. Here is what I do:

- Open a file, edit it and then save.

- use the "touch" command to update the time stamp of this file.

- Wait way more than the auto revert interval (which is set to 5 seconds
in my case).

- Try to make a change to the buffer corresponding to this file.

At this point, emacs says that the file has changed and asks whether I
really want to edit it. I was expecting emacs to auto revert this buffer
and allow me to edit it without further questions. So my question is, am
I looking at a bug, or a feature?

-- 
Timur Aydin

Re: global-auto-revert-mode and file time stamps

[Peter Dyballa]

Am 21.05.2013 um 15:36 schrieb Timur Aydin:

> At this point, emacs says that the file has changed and asks whether I
> really want to edit it. I was expecting emacs to auto revert this buffer
> and allow me to edit it without further questions. So my question is, am
> I looking at a bug, or a feature?

GNU Emacs will never automatically return to a previous state of the file. That's left up to you. What it does is, that it warns you, that it gives you information to make better decisions.

This is OK with me.

--
Greetings

  Pete

Don't just do something, sit there.

Re: global-auto-revert-mode and file time stamps

[Timur Aydin]

On 5/21/2013 8:26 PM, Peter Dyballa wrote:
> GNU Emacs will never automatically return to a previous state of the file. That's left up to you. What it does is, that it warns you, that it gives you information to make better decisions.

I don't want emacs to return the file to its previous state. 
global-auto-revert-mode doesn't do that, anyway. global-auto-revert-mode 
detects that a file has been changed on disc, and if I haven't made any 
edits to that file, it reverts the file _AUTOMATICALL_, without asking 
any questions. So that works as expected.

What doesn't work is, if only the timestamp of the file changes (touch 
filename), then emacs doesn't autorevert it, and instead tells me that 
it changed and asks whether I want to really edit it.

Hope this makes it clear...

-- 
Timur Aydin

Re: global-auto-revert-mode and file time stamps

[Michael Albinus]

Timur Aydin <ta@taydin.org> writes:

> Hi,

Hi,

> At this point, emacs says that the file has changed and asks whether I
> really want to edit it. I was expecting emacs to auto revert this buffer
> and allow me to edit it without further questions. So my question is, am
> I looking at a bug, or a feature?

I could reproduce the problem. I will check tomorrow what's up. Likely,
it is because the new file change notification mechanism introduced with
Emacs 24.3.50.

Best regards, Michael.

Re: global-auto-revert-mode and file time stamps

[Michael Albinus]

Michael Albinus <michael.albinus@gmx.de> writes:

Hi,

> I could reproduce the problem. I will check tomorrow what's up. Likely,
> it is because the new file change notification mechanism introduced with
> Emacs 24.3.50.

I've fixed this in the trunk.

Best regards, Michael.

Re: global-auto-revert-mode and file time stamps

[Timur Aydin]

On 5/22/2013 5:50 PM, Michael Albinus wrote:
> Michael Albinus <michael.albinus@gmx.de> writes:
>
> I've fixed this in the trunk.
 >

I can confirm that this problem is fixed. Thank you Michael.

-- 
Timur

Re: global-auto-revert-mode and file time stamps

[Ken Goldman]

On 5/21/2013 1:54 PM, Timur Aydin wrote:
>
> What doesn't work is, if only the timestamp of the file changes (touch
> filename), then emacs doesn't autorevert it, and instead tells me that
> it changed and asks whether I want to really edit it.

when I 'touch' on Windows or Linux, it does what you expect, not what 
you're observing.  It autoreverts the file.

I have this in .emacs:

(autoload 'auto-revert-mode "autorevert" nil t)
(autoload 'turn-on-auto-revert-mode "autorevert" nil nil)
(autoload 'global-auto-revert-mode "autorevert" nil t)
(global-auto-revert-mode 1)
(setq auto-revert-interval 2)
(global-set-key "\C-cr" 'revert-buffer)