From e049a25599c8abf693b35736e76ba4412cbc7cbc Mon Sep 17 00:00:00 2001
From: Gregory Heytings <gregory@heytings.org>
Date: Wed, 1 Feb 2023 18:06:49 +0000
Subject: [PATCH] Improve handling of Tramp methods by completion styles.

* lisp/net/tramp.el (tramp-methods-in-completions): New defcustom.
(tramp-completion-handle-file-name-all-completions): Use it.

* lisp/icomplete.el (icomplete--fido-mode-setup): Add 'basic'
after 'flex' in the completion styles, for cases where 'flex' does
not return anything.  This is required by Tramp.  Also set the new
defcustom 'tramp-methods-in-completions' to nil.

* doc/misc/tramp.texi (File name completion): Replace the footnote
about the limitation of the 'substring' and 'flex' completion
styles: suggest to use the new defcustom.

Fixes bug#50387, bug#51386, bug#52758, bug#53513, bug#54042 and
bug#60505.
---
 doc/misc/tramp.texi |  7 +++----
 lisp/icomplete.el   |  7 ++++++-
 lisp/net/tramp.el   | 21 +++++++++++++++++++--
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/doc/misc/tramp.texi b/doc/misc/tramp.texi
index 56436d32970..99f317dbbb8 100644
--- a/doc/misc/tramp.texi
+++ b/doc/misc/tramp.texi
@@ -3497,10 +3497,9 @@ File name completion
 Type @kbd{s h @value{postfixhop}} for the minibuffer completion to
 @samp{@value{prefix}ssh@value{postfixhop}}.  Typing @kbd{@key{TAB}}
 shows host names @value{tramp} extracts from @file{~/.ssh/config}
-@c bug#50387
-file, for example@footnote{Some completion styles, like
-@code{substring} or @code{flex}, require to type at least one
-character after the trailing @samp{@value{postfixhop}}.}.
+file, for example@footnote{For some completion styles, like
+@code{substring} or @code{flex}, it is necessary to set
+@code{tramp-methods-in-completions} to @code{t} for this to happen.}.
 
 @example
 @group
diff --git a/lisp/icomplete.el b/lisp/icomplete.el
index 014f38b2024..079e59e28e1 100644
--- a/lisp/icomplete.el
+++ b/lisp/icomplete.el
@@ -414,7 +414,12 @@ icomplete--fido-mode-setup
                 icomplete-show-matches-on-no-input t
                 icomplete-hide-common-prefix nil
                 icomplete-scroll (not (null icomplete-vertical-mode))
-                completion-styles '(flex)
+                ;; The 'basic' style is required by Tramp.  See
+                ;; bug#51386, bug#52758, bug#53513, bug#54042 and
+                ;; bug#60505.
+                completion-styles '(flex basic)
+                ;; Tell Tramp to display its methods lazily.
+                tramp-methods-in-completions nil
                 completion-flex-nospace nil
                 completion-ignore-case t
                 read-buffer-completion-ignore-case t
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 1916d50af03..533186d1633 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -812,6 +812,21 @@ tramp-syntax
   :initialize #'custom-initialize-default
   :set #'tramp-set-syntax)
 
+(defcustom tramp-methods-in-completions t
+  "How Tramp methods are displayed while completing file names.
+
+When t, Tramp methods are displayed unconditionally when
+completing file names, that is, as soon as completions are
+requested for the root directory.
+
+When nil, Tramp methods are displayed lazily when completing file
+names, that is, they are displayed only when no actual file in
+the root directory matches the current user input."
+  :type '(choice (const :tag "Unconditionally" t)
+                 (const :tag "Lazily" nil))
+  :require 'tramp
+  :version "29.1")
+
 (defvar tramp-prefix-format)
 (defvar tramp-prefix-regexp)
 (defvar tramp-method-regexp)
@@ -3022,8 +3037,10 @@ tramp-completion-handle-file-name-all-completions
 			       (delq nil all-user-hosts)))))
 
 	    ;; Possible methods.
-	    (setq result
-		  (append result (tramp-get-completion-methods m)))))))
+	    (unless (and (string-empty-p method)
+			 (not tramp-methods-in-completions))
+	      (setq result
+		    (append result (tramp-get-completion-methods m))))))))
 
     ;; Unify list, add hop, remove nil elements.
     (dolist (elt result)
-- 
2.39.0