bug#28905: 11.90.2.2017-07-25; TeX-documentation-texdoc blocks

[Ikumi Keita]

Hi Fran, Mosè and all, I'm responding to one year old thread.

>>>>> "Fran Burstall (Gmail)" <address@hidden> writes:
> Thanks, Moisè, for looking into this and thank you Keita for verifying the
> issue.

> I shall use tex-doc for the time being.

After struggling with this problem again, it seems that I managed to
find out a solution.  The patch listed below resolves the problem on my
environment.  Could you please try it?

If it fixes the problem without harming other's environments, I'll
install this in the git repository.

Regards,
Ikumi Keita

diff --git a/tex.el b/tex.el
index 9995af3f..2d3942f3 100644
--- a/tex.el
+++ b/tex.el
@@ -6350,7 +6350,27 @@ the number of the file to view, anything else to skip: 
") list)))
        ;; Called without prefix argument: just run "texdoc --view <pkg>" and
        ;; show the output, so that the user is warned in case it doesn't find
        ;; the documentation or "texdoc" is not available.
-       (message (shell-command-to-string (concat "texdoc --view " pkg)))))))
+       (message
+        ;; The folowing code to the end of `defun' used to be just
+        ;; (shell-command-to-string (concat "texdoc --view " pkg))
+        ;; , but in some cases it blocks emacs until the user quits
+        ;; the viewer (bug#28905).
+        (with-output-to-string
+          (let* (;; Use pipe rather than pty because the latter
+                 ;; causes atril (evince variant viewer) to exit
+                 ;; before showing anything.
+                 (process-connection-type nil)
+                 (process (start-process-shell-command
+                           "Doc view" standard-output
+                           (concat "texdoc --view " pkg))))
+            ;; Suppress the message "Process Doc view finished".
+            (set-process-sentinel process #'ignore)
+            ;; Kill temp buffer without query.  This is necessary if
+            ;; the underneath shell can't find the texdoc binary, at
+            ;; least for some environment.
+            (set-process-query-on-exit-flag process nil)
+            ;; Don't discard shell output.
+            (accept-process-output process))))))))
 
 (defun TeX-goto-info-page ()
   "Read documentation for AUCTeX in the info system."