Subject: bug#16197: 24.3.50; no completion on commands following "sudo" in shell and eshell

From: Stefan Monnier <[email-masked]>
Date: Sat, 26 Sep 2020 18:17:33 -0400

>> Same here, I'd think that the "command name" is "xargs", but rather than
>> argue about this philosophical point, it's probably better to focus on
>> more concrete cases where this return value is a problem.
>
> I think I read somewhere that Thierry is no longer working on Emacs
> stuff...  Let's see...  Oh, here:
>
> https://news.ycombinator.com/item?id=24449883
>
> Hm, that's only about Helm...
>
> Anyway, this doesn't help with the sudo case, I guess?

The sudo case is the same as xargs, so it's a simple matter of
duplicating the pcomplete/xargs (or making an alias) as in the patch below.

        Stefan

diff --git a/lisp/pcmpl-unix.el b/lisp/pcmpl-unix.el
index dc0d729849..8d4e7ea33d 100644
--- a/lisp/pcmpl-unix.el
+++ b/lisp/pcmpl-unix.el
@@ -83,10 +83,14 @@ pcomplete/rm
 ;;;###autoload
 (defun pcomplete/xargs ()
   "Completion for `xargs'."
-  (pcomplete-here (funcall pcomplete-command-completion-function))
+  ;; FIXME: Add completion of xargs-specific arguments.
+  (funcall pcomplete-command-completion-function)
   (funcall (or (pcomplete-find-completion-function (pcomplete-arg 1))
 	       pcomplete-default-completion-function)))
 
+;; FIXME: Add completion of sudo-specific arguments.
+(defalias 'pcomplete/sudo #'pcomplete/xargs)
+
 ;;;###autoload
 (defalias 'pcomplete/time 'pcomplete/xargs)
 
diff --git a/lisp/shell.el b/lisp/shell.el
index e574aac99d..d2c41a9690 100644
--- a/lisp/shell.el
+++ b/lisp/shell.el
@@ -461,9 +461,12 @@ shell-command-completion-function
 This is the value of `pcomplete-command-completion-function' for
 Shell buffers.  It implements `shell-completion-execonly' for
 `pcomplete' completion."
-  (pcomplete-here (pcomplete-entries nil
-				     (if shell-completion-execonly
-					 'file-executable-p))))
+  (if (pcomplete-match "/")
+      (pcomplete-here (pcomplete-entries nil
+					 (if shell-completion-execonly
+					     'file-executable-p)))
+    (pcomplete-here
+     (nth 2 (shell--command-completion-data)))))
 
 (defun shell-completion-vars ()
   "Setup completion vars for `shell-mode' and `read-shell-command'."