bug#47205: Re: bug#47205: 27.1.91; [bug] unexpected input event interrupted expand-file

[Lin Sun]

Hi Michael,

 

If the 'tramp-archive already be loaded, follow command lines will get expected path:

$ emacs --batch --eval "(require 'tramp-archive)" --eval "(message \"%s %s\" (catch 'input

  (let ((throw-on-input 'input)) (expand-file-name \"a.iso/b\" \"/\"))) last-input-event)"

 

Contrasting with previous command lines, the behavior is hard to understand.

 

The line `(let ((throw-on-input 'input))…`  cause `read-event` throw a ‘input’ event,

and according the document of `throw-on-input`:

> throw-on-input is a variable defined in ‘keyboard.c’.

> Documentation:

> If non-nil, any keyboard input throws to this symbol.

> The value of that variable is passed to ‘quit-flag’ and later causes a

> peculiar kind of quitting.

It seems only “keyboard” input should trigger a ‘input event, so dbus event should be silence for this case.

 

 

From: Michael Albinus
Sent: Wednesday, March 17, 2021 19:51
To: LinSun via Bug reports for GNU Emacs, the Swiss army knife of text editors
Cc: 47205@debbugs.gnu.org; LinSun
Subject: Re: bug#47205: 27.1.91; [bug] unexpected input event interrupted expand-file

 

LinSun via "Bug reports for GNU Emacs, the Swiss army knife of text

editors" <bug-gnu-emacs@gnu.org> writes:

 

Hi,

 

> There is a bug that `helm-projectile-find-file' is interrupted by an

> unexpected input event. After inspecting emacs code, I found it can

> simply reproduce by follow code, and the expected out is a path,

> while actually result is t:

> 

> emacs --batch --eval "(message \"%s\" (catch 'input

> (let ((throw-on-input 'input)) (expand-file-name \"a.iso/b\"

> \"/\"))))"

> 

> From the backtrace, it seems caused by `tramp-archive-file-name-handler’.

> 

> How to avoid input event in this situation? Thanks

 

This input event is expected. You expand the file name "a.iso/b", which

is recognized as archive due to the ".iso/" extension. This triggers the

Tramp archive file name handler, which is implemented using D-Bus. The

input event is a D-Bus event, as you can see:

 

--8<---------------cut here---------------start------------->8---

# emacs --batch --eval "(message \"%s %s\" (catch 'input (let ((throw-on-input 'input)) (expand-file-name \"a.iso/b\" \"/\"))) last-input-event)"

 

=> t (dbus-event :system 2 2 org.freedesktop.DBus :1.527417 nil nil nil dbus-call-method-handler)

--8<---------------cut here---------------end--------------->8---

 

Which problem do you have with D-Bus events?

 

Best regards, Michael.