Subject: bug#65356: 30.0.50; [wishlist] Support Tramp method, user name and host name completion in eshell

From: Michael Albinus <[email-masked]>
Date: Sun, 20 Aug 2023 12:53:09 +0200

Jim Porter <[email-masked]> writes:

Hi Jim,

> This works for me, and I think it makes sense overall. It might be
> nice to add the ability to ignore remote file names in Eshell when
> completing an argument to an external command (which doesn't
> understand Tramp syntax), but that would probably require a bunch of
> work on the Eshell side, and we can worry about that later, I think.

As POC, I've written the appended patch. It works for me in a simple
case, but I'm pretty sure it needs to handle more cases. Since I'm not
so familiar with Eshell, I let it to you :-)

... unless you say it is sufficient ATM.

Best regards, Michael.

diff --git a/lisp/eshell/em-cmpl.el b/lisp/eshell/em-cmpl.el
index 732bbb3f1fa..25dccbd695c 100644
--- a/lisp/eshell/em-cmpl.el
+++ b/lisp/eshell/em-cmpl.el
@@ -148,6 +148,10 @@ eshell-cmpl-dir-ignore
   (eshell-cmpl--custom-variable-docstring 'pcomplete-dir-ignore)
   :type (get 'pcomplete-dir-ignore 'custom-type))

+(defcustom eshell-cmpl-remote-file-ignore nil
+  (eshell-cmpl--custom-variable-docstring 'pcomplete-remote-file-ignore)
+  :type (get 'pcomplete-remote-file-ignore 'custom-type))
+
 (defcustom eshell-cmpl-ignore-case (eshell-under-windows-p)
   (eshell-cmpl--custom-variable-docstring 'completion-ignore-case)
   :type (get 'completion-ignore-case 'custom-type))
@@ -248,6 +252,8 @@ eshell-cmpl-initialize
               eshell-cmpl-file-ignore)
   (setq-local pcomplete-dir-ignore
               eshell-cmpl-dir-ignore)
+  (setq-local pcomplete-remote-file-ignore
+              eshell-cmpl-remote-file-ignore)
   (setq-local completion-ignore-case
               eshell-cmpl-ignore-case)
   (setq-local pcomplete-autolist
@@ -325,6 +331,15 @@ eshell-complete--eval-argument-form
             "Failed to evaluate argument form during completion: %S" arg)
      (propertize "\0" 'eshell-argument-stub 'error))))

+;; Code stolen from `eshell-plain-command'.
+(defun eshell-external-command-p (command)
+  "Whether an external command shall be called."
+  (let* ((esym (eshell-find-alias-function command))
+	 (sym (or esym (intern-soft command))))
+    (not (and sym (fboundp sym)
+	      (or esym eshell-prefer-lisp-functions
+		  (not (eshell-search-path command)))))))
+
 (defun eshell-complete-parse-arguments ()
   "Parse the command line arguments for `pcomplete-argument'."
   (when (and eshell-no-completion-during-jobs
@@ -406,6 +421,14 @@ eshell-complete-parse-arguments
        args posns)
       (setq args (nreverse evaled-args)
             posns (nreverse evaled-posns)))
+    ;; Determine, whether remote file names shall be completed.  They
+    ;; shouldn't for external commands, or when in a pipe.  Respect
+    ;; also `eshell-cmpl-remote-file-ignore', which could be set by
+    ;; the user.
+    (setq-local pcomplete-remote-file-ignore
+                (or eshell-cmpl-remote-file-ignore
+                    eshell-in-pipeline-p ; does not work
+                    (eshell-external-command-p (car args))))
     ;; Convert arguments to forms that Pcomplete can understand.
     (cons (mapcar
            (lambda (arg)