Double-click opens the wrong file

Double-click opens the wrong file

[Nick Helm]

Occasionally, when I double click a file to edit it, Emacs will visit a
different file instead.

Repeated double clicking visits a succession of incorrect files, until
Emacs eventually settles on the right one.

The files are all ones I have been working with recently, although not
necessarily in Emacs. The visited file need not be in the same location
or even exist at all – Emacs will quite happily visit a recently deleted
file.

Only double clicking files associated with Emacs (26.0.90) seems to be
affected. Visiting with find-file, drag and drop, and the menu-bar, as
well as other versions of Emacs, have the expected behaviour.

I would open a bug, but it feels like an OS problem (I'm on macOS
10.12.6), rather than a flaw in Emacs.

Any ideas what's going on or how to fix/debug this issue?

RE: Double-click opens the wrong file

[Drew Adams]

> Occasionally, when I double click a file to edit it, Emacs will visit a
> different file instead.
> 
> Repeated double clicking visits a succession of incorrect files, until
> Emacs eventually settles on the right one.
> 
> The files are all ones I have been working with recently, although not
> necessarily in Emacs. The visited file need not be in the same location
> or even exist at all – Emacs will quite happily visit a recently deleted
> file.
> 
> Only double clicking files associated with Emacs (26.0.90) seems to be
> affected. Visiting with find-file, drag and drop, and the menu-bar, as
> well as other versions of Emacs, have the expected behaviour.
> 
> I would open a bug, but it feels like an OS problem (I'm on macOS
> 10.12.6), rather than a flaw in Emacs.
> 
> Any ideas what's going on or how to fix/debug this issue?

One place to start is to use `C-h k' and then double-click
wherever you notice the problem.  That should at least tell
you what Emacs command is being invoked by that double-click.

Re: Double-click opens the wrong file

[Eli Zaretskii]

> From: Nick Helm <nick@tenpoint.co.nz>
> Date: Wed, 01 Nov 2017 16:07:04 +1300
> 
> Occasionally, when I double click a file to edit it, Emacs will visit a
> different file instead.

Please tell how you set this up, and in what application do you
double-click on a file to have it visited in Emacs.

Also, is the file actually visited displayed near the name you clicked
on, or is it entirely unrelated?

IOW, please add details.

Thanks.

Re: Double-click opens the wrong file

[Nick Helm]

On Wed,  1 Nov 2017, Eli Zaretskii wrote:

>> Occasionally, when I double click a file to edit it, Emacs will visit
>> a different file instead.
>
> Please tell how you set this up, and in what application do you
> double-click on a file to have it visited in Emacs.
>
> Also, is the file actually visited displayed near the name you clicked
> on, or is it entirely unrelated?
>
> IOW, please add details.

Sorry, I should have been much clearer.

The issue occurs when I double click a file on my desktop or in a file
browser window. That is, I click on a file within the OS and rely on the
OS's file association mechanism to visit the file in Emacs.

I can reproduce the issue with this generalised recipe:

+ Launch Emacs using the GUI bundle Emacs.app
+ Within Emacs, find-file ~/work/file1.org. Edit, save, kill.
+ Within Emacs, find-file ~/config/file2.txt. Edit, save, kill.
+ With the mouse, click on the OS desktop. Emacs loses focus.
+ On the desktop, double click file3.el (~/Desktop/file3.el).
+ Focus returns to Emacs. Emacs visits file1.org.
+ Return to the desktop and again double click file3.el.
+ Emacs gains focus and visits file2.txt.
+ Double click file3.el a third time.
+ Emacs gains focus and opens file3.el as expected.

The file that actually opens following the double click is not logically
or physically close to (in file-system or GUI terms) the clicked file.
They are chronologically linked, however – that is, they are visited in
the same order as my original edits.

Thanks.

Re: Double-click opens the wrong file

[Nick Helm]

On Wed,  1 Nov 2017 at 16:26:56 +1300, Drew Adams wrote:

>> Occasionally, when I double click a file to edit it, Emacs will visit
>> a different file instead.
>
> One place to start is to use `C-h k' and then double-click wherever
> you notice the problem. That should at least tell you what Emacs
> command is being invoked by that double-click.

That's good advice. I had no idea C-h k could capture incoming events
from the OS...

Priming C-h k and double clicking a file on the desktop points me toward
`ns-open-file-select-line' which is bound to <ns-open-file-line>. I
guess the latter is the incoming event.

The docstring also mentions `ns-input-file', which looks like it
contains the name of the file from the incoming event. The next time the
issue occurs, this will be one to watch.

Thanks.

Re: Double-click opens the wrong file

[Eli Zaretskii]

> From: Nick Helm <nick@tenpoint.co.nz>
> Date: Wed, 01 Nov 2017 20:27:08 +1300
> 
> + Launch Emacs using the GUI bundle Emacs.app
> + Within Emacs, find-file ~/work/file1.org. Edit, save, kill.
> + Within Emacs, find-file ~/config/file2.txt. Edit, save, kill.
> + With the mouse, click on the OS desktop. Emacs loses focus.
> + On the desktop, double click file3.el (~/Desktop/file3.el).
> + Focus returns to Emacs. Emacs visits file1.org.
> + Return to the desktop and again double click file3.el.
> + Emacs gains focus and visits file2.txt.
> + Double click file3.el a third time.
> + Emacs gains focus and opens file3.el as expected.
> 
> The file that actually opens following the double click is not logically
> or physically close to (in file-system or GUI terms) the clicked file.
> They are chronologically linked, however – that is, they are visited in
> the same order as my original edits.

Please report this as a bug, so that our NS experts could take care of
this.

Thanks.