Bug: C-u C-u C-c C-o opens pdf links in docview, belying the docstring [8.3.4 (8.3.4-39-ge0acd8-elpaplus @ /home/jorge/.emacs.d/elpa/org-plus-contrib-20160418/)]

Bug: C-u C-u C-c C-o opens pdf links in docview, belying the docstring [8.3.4 (8.3.4-39-ge0acd8-elpaplus @ /home/jorge/.emacs.d/elpa/org-plus-contrib-20160418/)]

[Jorge Peixoto de Morais Neto]

Create an Org file with a link to an existing PDF file.  For example:

[[file:~/circulant_diagonalization.pdf][file:~/circulant_diagonalization.pdf]]

(assuming the mentioned file exists at that path).  In an attempt to open the
PDF in the system viewer, position point over the link and type
C-u C-u C-c C-o.

The link opens in DocView, belying the docstring, which says:
    With a double prefix argument, try to open outside of Emacs, in the
    application the system uses for this file type.

I reproduced with an empty Emacs init file.  I use Ubuntu 16.04.  The default
PDF application is Okular.

Emacs  : GNU Emacs 25.0.93.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9)
 of 2016-04-22
Package: Org-mode version 8.3.4 (8.3.4-39-ge0acd8-elpaplus @
/home/jorge/.emacs.d/elpa/org-plus-contrib-20160418/)

current state:
==============
(setq
 org-tab-first-hook '(org-hide-block-toggle-maybe org-babel-hide-result-
toggle-maybe org-babel-header-arg-expand)
 org-speed-command-hook '(org-speed-command-default-hook org-babel-speed-
command-hook)
 org-occur-hook '(org-first-headline-recenter)
 org-metaup-hook '(org-babel-load-in-session-maybe)
 org-confirm-shell-link-function 'yes-or-no-p
 org-after-todo-state-change-hook '(org-clock-out-if-current)
 org-src-mode-hook '(org-src-babel-configure-edit-buffer org-src-mode-
configure-edit-buffer)
 org-agenda-before-write-hook '(org-agenda-add-entry-text)
 org-babel-pre-tangle-hook '(save-buffer)
 org-mode-hook '(#[nil "\300\301\302\303\304$\207" [org-add-hook change-major-
mode-hook org-show-block-all append local] 5]
		 #[nil "\300\301\302\303\304$\207" [org-add-hook change-major-
mode-hook org-babel-show-result-all append local] 5]
		 org-babel-result-hide-spec org-babel-hide-all-hashes org-
eldoc-load)
 org-archive-hook '(org-attach-archive-delete-maybe)
 org-ctrl-c-ctrl-c-hook '(org-babel-hash-at-point org-babel-execute-safely-
maybe)
 org-cycle-hook '(org-cycle-hide-archived-subtrees org-cycle-hide-drawers org-
cycle-show-empty-lines
		  org-optimize-window-after-visibility-change)
 org-confirm-elisp-link-function 'yes-or-no-p
 org-metadown-hook '(org-babel-pop-to-session-maybe)
 org-clock-out-hook '(org-clock-remove-empty-clock-drawer)
 )

-- 
- I am Brazilian.  I hope my English is correct and I welcome corrections.
- Please adopt free formats like PDF, ODF, LaTeX, Vorbis, Opus, WebM and 7z.
- Free software for Android: https://f-droid.org/

Re: Bug: C-u C-u C-c C-o opens pdf links in docview, belying the docstring [8.3.4 (8.3.4-39-ge0acd8-elpaplus @ /home/jorge/.emacs.d/elpa/org-plus-contrib-20160418/)]

[Kyle Meyer]

Jorge Peixoto de Morais Neto <jorge13515@gmail.com> writes:
> In an attempt to open the PDF in the system viewer, position point
> over the link and type C-u C-u C-c C-o.
>
> The link opens in DocView, belying the docstring, which says:
>     With a double prefix argument, try to open outside of Emacs, in the
>     application the system uses for this file type.

I'd guess that it does try to open it in an external application, but,
after it can't figure out what that should be, it falls back to Emacs.
You could step through the call to org-open-file to get a better
understanding for what it is trying.

> I reproduced with an empty Emacs init file.  I use Ubuntu 16.04.  The default
> PDF application is Okular.

I don't know how Ubunutu assigns default applications, but org-open-file
looks at mailcap assignments by default on GNU/Linux systems (see
org-file-apps-defaults-gnu).  You can also specify an
extension-application mapping using the org-file-apps variable.

--
Kyle

Re: Bug: C-u C-u C-c C-o opens pdf links in docview, belying the docstring [8.3.4 (8.3.4-39-ge0acd8-elpaplus @ /home/jorge/.emacs.d/elpa/org-plus-contrib-20160418/)]

[Jorge Peixoto de Morais Neto]

On Sat, 2016-04-23 at 17:21 -0400, Kyle Meyer wrote:
> I don't know how Ubunutu assigns default applications, but org-open-file
> looks at mailcap assignments by default on GNU/Linux systems (see
> org-file-apps-defaults-gnu).  You can also specify an
> extension-application mapping using the org-file-apps variable.
There seems to be a Freedesktop standard related to this.  There is even a
Freedesktop cli command (xdg-open) to open a URL (remote or local) in the
user's preferred application.  I really believe Emacs should integrate with
this standard by default.  For now I have manually customized org-file-apps
(and I will need to manually customize it again if I change my preferred PDF
viewer[1]), but Emacs would be more user-friendly if it integrated with the
Freedesktop standard.

One significant roadblock for greater Emacs adoption is that countless
problems that other programs solve automagically, must be manually configured
in Emacs, and they add up.

I hope I don't sound ungrateful.

Regards

* Notes
[1]: Of course I tried to specify xdg-open as the PDF viewer (so Emacs would
automatically open the PDF in whatever viewer I have currently configured
through Ubuntu GUI), but it didn't work (C-c C-o would do nothing), so I fell
back to manually specifying Okular.

-- 
- I am Brazilian.  I hope my English is correct and I welcome corrections.
- Please adopt free formats like PDF, ODF, LaTeX, Vorbis, Opus, WebM and 7z.
- Free software for Android: https://f-droid.org/