Make "rlogin" method obsolete in url*.el

* lisp/url/url-about.el (url-probe-protocols): Remove "rlogin".
* lisp/url/url-gw.el (url-gateway-rlogin-host)
(url-gateway-rlogin-user-name, url-gateway-rlogin-parameters)
(url-open-rlogin): Make obsolete.  (Bug#56891)
(url-open-stream):
* lisp/url/url-misc.el (url-do-terminal-emulator): Warn when using
"rlogin".
(url-rlogin): Make obsolete.
* lisp/url/url-vars.el (url-gateway-method): Remove "rlogin"
choice.

* lisp/url/url-gw.el (url-gw-rlogin-obsolete-warned-once)
* lisp/url/url-misc.el (url-misc-rlogin-obsolete-warned-once): New
variables, immediately marked obsolete.

* doc/misc/url.texi (telnet/tn3270): Rename section from
"rlogin/telnet/tn3270".
(Gateways in general, Customization): Don't mention "rlogin"
method.

doc/misc/url.texi

@@ -380,7 +380,7 @@ for specific schemes.
 * info::                        Emacs "Info" pages.
 * mailto::                      Sending email.
 * news/nntp/snews::             Usenet news.
-* rlogin/telnet/tn3270::        Remote host connectivity.
+* telnet/tn3270::               Remote host connectivity.
 * irc::                         Internet Relay Chat.
 * data::                        Embedded data URLs.
 * nfs::                         Networked File System.
@@ -675,9 +675,8 @@ environment variable @samp{NNTPSERVER}, or @samp{news} if that
 environment variable is unset.
 @end defopt
 
-@node rlogin/telnet/tn3270
-@section rlogin, telnet and tn3270
-@cindex rlogin
+@node telnet/tn3270
+@section telnet and tn3270
 @cindex telnet
 @cindex tn3270
 @cindex terminal emulation
@@ -694,10 +693,10 @@ telnet://@var{user}:@var{password}@@@var{host}:@var{port}
 but the @var{password} component is ignored.  By default, the
 @code{telnet} scheme is handled via Tramp (@pxref{Tramp}).
 
-To handle rlogin, telnet and tn3270 URLs, a @code{rlogin},
-@code{telnet} or @code{tn3270} (the program names and arguments are
-hardcoded) session is run in a @code{terminal-emulator} buffer.
-Well-known ports are used if the URL does not specify a port.
+To handle telnet and tn3270 URLs, a @code{telnet} or @code{tn3270}
+(the program names and arguments are hardcoded) session is run in a
+@code{terminal-emulator} buffer.  Well-known ports are used if the URL
+does not specify a port.
 
 @node irc
 @section irc
@@ -1039,12 +1038,6 @@ a list of symbols.  Possible values are:
 Use this method if you must first telnet and log into a gateway host,
 and then run telnet from that host to connect to outside machines.
 
-@item rlogin
-@cindex @command{rlogin}
-This method is identical to @code{telnet}, but uses @command{rlogin}
-to log into the remote machine without having to send the username and
-password over the wire every time.
-
 @item socks
 @cindex @sc{socks}
 Use if the firewall has a @sc{socks} gateway running on it.  The
@@ -1087,19 +1080,6 @@ The password to send when logging in.
 This is a regular expression that matches the shell prompt.
 @end defopt
 
-@defopt url-gateway-rlogin-host
-Host to @samp{rlogin} to before telnetting out.
-@end defopt
-@defopt url-gateway-rlogin-parameters
-Parameters to pass to @samp{rsh}.
-@end defopt
-@defopt url-gateway-rlogin-user-name
-User name to use when logging in to the gateway.
-@end defopt
-@defopt url-gateway-prompt-pattern
-This is a regular expression that matches the shell prompt.
-@end defopt
-
 @defopt socks-server
 This specifies the default server, it takes the form
 @w{@code{("Default server" @var{server} @var{port} @var{version})}}
@@ -1327,8 +1307,6 @@ from the local machine.  The supported methods are:
 @table @code
 @item telnet
 Run telnet in a subprocess to connect;
-@item rlogin
-Rlogin to another machine to connect;
 @item socks
 Connect through a socks server;
 @item ssl

etc/NEWS

@@ -356,6 +356,18 @@ the major mode according to 'initial-major-mode', like at Emacs
 startup.  Previously, these functions ignored
 'initial-scratch-message' and left "*scratch*" in 'fundamental-mode'.
 
+---
+** The 'rlogin' method in the URL library is now obsolete.
+Emacs will now display a warning if you request a URL like
+"rlogin://foo@example.org".
+
+---
+** Setting 'url-gateway-method' to 'rlogin' is now obsolete.
+Emacs will now display a warning when setting it to that value.
+The user options 'url-gateway-rlogin-host',
+'url-gateway-rlogin-parameters', and 'url-gateway-rlogin-user-name'
+are also obsolete.
+
 ---
 ** The autoarg.el library is now marked obsolete.
 This library provides the 'autoarg-mode' and 'autoarg-kp-mode' minor

lisp/obsolete/url-about.el

@@ -32,7 +32,7 @@
   (or (get 'url-extension-protocols 'probed)
       (mapc (lambda (s) (url-scheme-get-property s 'name))
 	    (or (get 'url-extension-protocols 'schemes)
-		(let ((schemes '("info" "man" "rlogin" "telnet"
+                (let ((schemes '("info" "man" "telnet"
 				 "tn3270" "data" "snews")))
 		  (mapc (lambda (d)
 			  (mapc (lambda (f)

lisp/url/url-gw.el

@@ -28,8 +28,6 @@
 (require 'url-vars)
 (require 'url-parse)
 
-;; Fixme: support SSH explicitly or via a url-gateway-rlogin-program?
-
 (autoload 'socks-open-network-stream "socks")
 
 (defgroup url-gateway nil
@@ -51,17 +49,20 @@
   "What hostname to actually rlog into before doing a telnet."
   :type '(choice (const nil) string)
   :group 'url-gateway)
+(make-obsolete-variable 'url-gateway-rlogin-host nil "29.1")
 
 (defcustom url-gateway-rlogin-user-name nil
   "Username to log into the remote machine with when using rlogin."
   :type '(choice (const nil) string)
   :group 'url-gateway)
+(make-obsolete-variable 'url-gateway-rlogin-user-name nil "29.1")
 
 (defcustom url-gateway-rlogin-parameters '("telnet" "-8")
   "Parameters to `url-open-rlogin'.
 This list will be used as the parameter list given to rsh."
   :type '(repeat string)
   :group 'url-gateway)
+(make-obsolete-variable 'url-gateway-rlogin-parameters nil "29.1")
 
 (defcustom url-gateway-telnet-host nil
   "What hostname to actually login to before doing a telnet."
@@ -141,6 +142,7 @@ linked Emacs under SunOS 4.x."
 ;; Stolen from red gnus nntp.el
 (defun url-open-rlogin (name buffer host service)
   "Open a connection using rsh."
+  (declare (obsolete nil "29.1"))
   (if (not (stringp service))
       (setq service (int-to-string service)))
   (let ((proc (if url-gateway-rlogin-user-name
@@ -205,6 +207,9 @@ linked Emacs under SunOS 4.x."
 	(delete-region (point) (point-max)))
       proc)))
 
+(defvar url-gw-rlogin-obsolete-warned-once nil)
+(make-obsolete-variable url-gw-rlogin-obsolete-warned-once nil "29.1")
+
 ;;;###autoload
 (defun url-open-stream (name buffer host service &optional gateway-method)
   "Open a stream to HOST, possibly via a gateway.
@@ -255,7 +260,11 @@ overriding the value of `url-gateway-method'."
 			 ('telnet
 			  (url-open-telnet name buffer host service))
 			 ('rlogin
-			  (url-open-rlogin name buffer host service))
+                          (unless url-gw-rlogin-obsolete-warned-once
+                            (lwarn 'url :error "Setting `url-gateway-method' to `rlogin' is obsolete")
+                            (setq url-gw-rlogin-obsolete-warned-once t))
+                          (with-suppressed-warnings ((obsolete url-open-rlogin))
+                            (url-open-rlogin name buffer host service)))
 			 (_
 			  (error "Bad setting of url-gateway-method: %s"
 				 url-gateway-method))))))

lisp/url/url-misc.el

@@ -47,6 +47,9 @@
       (error "Malformed url: %s" (url-recreate-url url)))
     nil))
 
+(defvar url-misc-rlogin-obsolete-warned-once nil)
+(make-obsolete-variable url-misc-rlogin-obsolete-warned-once nil "29.1")
+
 (defun url-do-terminal-emulator (type server port user)
   (switch-to-buffer
    (apply
@@ -58,6 +61,9 @@
 	  (t (error "Unknown terminal emulator required: %s" type)))
     nil
     (cond ((eq type 'rlogin)
+           (unless url-misc-rlogin-obsolete-warned-once
+             (lwarn 'url :error "Method `rlogin' is obsolete")
+             (setq url-misc-rlogin-obsolete-warned-once t))
 	   (if user (list server "-l" user) (list server)))
 	  ((eq type 'telnet)
 	   (if port (list server port) (list server)))
@@ -74,7 +80,7 @@
   nil)
 
 ;;;###autoload
-(defalias 'url-rlogin 'url-generic-emulator-loader)
+(define-obsolete-function-alias 'url-rlogin #'url-generic-emulator-loader "29.1")
 ;;;###autoload
 (defalias 'url-telnet 'url-generic-emulator-loader)
 ;;;###autoload

lisp/url/url-vars.el

@@ -350,13 +350,11 @@ Should be a symbol specifying how to get a connection from the local machine.
 
 Currently supported methods:
 `telnet': Run telnet in a subprocess to connect;
-`rlogin': Rlogin to another machine to connect;
 `socks': Connect through a socks server;
 `tls': Connect with TLS;
 `ssl': Connect with SSL (deprecated, use `tls' instead);
 `native': Connect directly."
   :type '(radio (const :tag "Telnet to gateway host" :value telnet)
-		(const :tag "Rlogin to gateway host" :value rlogin)
 		(const :tag "Use SOCKS proxy" :value socks)
 		(const :tag "Use SSL/TLS for all connections" :value tls)
 		(const :tag "Use SSL for all connections (obsolete)" :value ssl)