crux-open-with silently fails

[justbur]

I'm switching some of my own functions over to crux ones. I was wondering if you knew the answer to this problem I've had with opening files externally.

crux-open-with does nothing for me in dired on a pdf for example. If I switch the start-process line to

    (call-process program nil 0 nil current-file-name)

then it works fine, meaning something is failing in start-process. I did some debugging but wasn't able to find anything. It just seems to silently fail.

My version string is
GNU Emacs 25.1.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.22.4) of 2016-12-15

If you have any ideas, I'd appreciate it. xdg-open works fine from the command line and using call-process as above.

By the way, I don't think there is any downside to using call-process here, but I'd like to know why start-process is failing for me.

[justbur]

Dug into this a little more. I see what's happening I think, but I don't understand why this is different behavior on my computer since I assume it's working for others.

The behavior with call-process vs start-process is the same as the behavior with shell-command vs async-shell-command.

1. If I do M-! xdg-open test.pdf, test.pdf opens fine.
2. If I do M-& xdg-open test.pdf, I get a message that "xdg-open test.pdf" finished with no program opening.
3. If I do M-& xdg-open test.pdf && sleep 3, the pdf opens for 3 seconds and closes.

So clearly emacs is killing evince (the pdf program) for me. This is logical if it's killing a whole process tree and evince is a subprocess, but it does not seem consistent with how xdg-open works in a shell for example.

Running xdg-open test.pdf in a shell does not make evince a subprocess of the shell so killing the shell does not kill evince.

I will file an emacs bug for this and see what they say, since this doesn't seem specific to crux anymore.

[justbur]

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25234

[bbatsov]

ОК, thanks for bringing this up. Let me know when you figure out the best course of action.

[justbur]

@bbatsov I'm out of ideas for the moment. I'm not sure it's an emacs bug, but at the same time I can't set up an environment on my computer in which crux-open-with actually works. I'm on fedora 25 with gnome right now. I've tried xfce and ubuntu unity in a vm (with emacs 24.5), and all had the same behavior. Presumably it works for you. What is your setup?

Plus in your blog post you don't use an async command. Can we just switch to call-process? This works in all of the cases I've tried. It's the async versions that fail for me.

[bbatsov]

What is your setup?

OS X. There it works just fine.

[justbur]

From the emacs bug report, I think it's an underlying problem with gvfs-open (which xdg-open uses). see here

Using a synchronous call as I did in PR #38 seems like the best option to me (at least for xdg-open).