Implement command completion in remote shells. (Bug#31704)

* doc/lispref/files.texi (Locating Files): Describe optional
argument REMOTE of `executable-find'.
(Magic File Names): Add `exec-path'.

* doc/lispref/processes.texi (Subprocess Creation): Describe
function `exec-path'.

* doc/misc/tramp.texi (Remote programs): Explain refresh of search
paths by `tramp-cleanup-this-connection'.

* etc/NEWS: Mention 'exec-path' and 'executable-find'.

* lisp/files.el (exec-path): New defun.
(executable-find): Add optional argument REMOTE.

* lisp/shell.el (shell-completion-vars): Set `comint-file-name-prefix'.
(shell--command-completion-data): Use `(exec-path)'.  (Bug#31704)

* lisp/net/ange-ftp.el (exec-path):
* lisp/net/tramp.el (tramp-file-name-for-operation):
* lisp/net/tramp-adb.el (tramp-adb-file-name-handler-alist):
* lisp/net/tramp-archive.el (tramp-archive-file-name-handler-alist):
* lisp/net/tramp-gvfs.el (tramp-gvfs-file-name-handler-alist):
* lisp/net/tramp-sh.el (tramp-sh-file-name-handler-alist):
* lisp/net/tramp-smb.el (tramp-smb-file-name-handler-alist)
<exec-path>: Add handler.

* lisp/net/tramp-adb.el (tramp-adb-handle-exec-path): New defun.
(tramp-adb-maybe-open-connection): Do not set "remote-path"
connection property.

* lisp/net/tramp-compat.el (tramp-compat-exec-path): New defun.

* lisp/net/tramp-sh.el (tramp-sh-handle-exec-path): New defun.

* lisp/net/tramp.el (tramp-eshell-directory-change): Use it.

* test/lisp/net/tramp-archive-tests.el
(tramp-archive-test38-make-nearby-temp-file)
(tramp-archive-test41-file-system-info)
(tramp-archive-test43-auto-load)
(tramp-archive-test43-delay-load): Rename.

* test/lisp/net/tramp-tests.el (tramp-test34-exec-path): New test.
(tramp-test36-make-auto-save-file-name)
(tramp-test37-find-backup-file-name)
(tramp-test38-make-nearby-temp-file)
(tramp-test39-special-characters)
(tramp-test39-special-characters-with-stat)
(tramp-test39-special-characters-with-perl)
(tramp-test39-special-characters-with-ls, tramp-test40-utf8)
(tramp-test40-utf8-with-stat, tramp-test40-utf8-with-perl)
(tramp-test40-utf8-with-ls, tramp-test41-file-system-info)
(tramp-test42-asynchronous-requests, tramp-test43-auto-load)
(tramp-test43-delay-load, tramp-test43-recursive-load)
(tramp-test43-remote-load-path, tramp-test44-unload): Rename.

1 files changed, 13 insertions, 5 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 632627b241d..709c446849b 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -145,6 +145,14 @@ regular expression was previously invalid, but is now accepted:
 ---
 ** The German prefix and postfix input methods now support Capital sharp S.
 
++++
+** The new function 'exec-path' returns a directory list from a remote host.
+
++++
+** Function 'executable-find' supports an optional argument REMOTE.
+This triggers to search a program name on the remote host indicated by
+'default-directory'.
+
 
 * Editing Changes in Emacs 27.1
 
@@ -436,7 +444,6 @@ It can be used to set any buffer as the next one to be used by
 This means that pressing C-M-SPACE now selects the entire tree by
 default, and not just the opening element.
 
-
 ** Eshell
 
 ---
@@ -454,11 +461,15 @@ To restore the old behavior, use
 Previously eshell/kill would fail if provided a kill signal to send to the
 process.  It now accepts signals specified either by name or by its number.
 
+** Shell
+
+---
+*** Program name completion inside remote shells works now as expected.
+
 ** Pcomplete
 *** The function 'pcomplete-uniquify-list' has been renamed from
 'pcomplete-uniqify-list'.
 
-
 ** Auth-source
 
 ---
@@ -755,7 +766,6 @@ will be chosen even if you have an entry for image/* in your
 overrides all system and Emacs-provided defaults.  To get the old
 method back, set 'mailcap-prefer-mailcap-viewers' to nil.
 
-
 ** URL
 
 *** The file: handler no longer looks for index.html in directories if
@@ -763,14 +773,12 @@ you ask it for a file:///dir URL.  Since this is a low-level library,
 such decisions (if they are to be made at all) are left to
 higher-level functions.
 
-
 ** image-mode
 
 *** image-mode started using ImageMagick by default for all images
 some years back.  It now respects 'imagemagick-types-inhibit' as a way
 to disable that.
 
-
 +++
 ** The new function 'read-answer' accepts either long or short answers
 depending on the new customizable variable 'read-answer-short'.