Remove dead code in `eshell/diff`

* lisp/eshell/em-unix.el (eshell/diff): Adjust for diff-mode; do not
set 'compilation-finish-functions', as it is never used.  (Bug#65245)
(eshell-diff-quit): Make into an obsolete function alias for 'ignore';
the command has been a no-op for close to two decades.
(eshell-diff-window-config): Make obsolete.

diff --git a/lisp/eshell/em-unix.el b/lisp/eshell/em-unix.el
index b7ef0f0c40cad51ed968335eb0665b4d6e9ca786..a8c86b925bcd854fc911d14f3f0c703dd5866ecf 100644 (file)
--- a/lisp/eshell/em-unix.el
+++ b/lisp/eshell/em-unix.el
@@ -998,14 +998,6 @@ Show wall-clock time elapsed during execution of COMMAND.")
   "Make \"whoami\" Tramp aware."
   (eshell-user-login-name))
 
-(defvar eshell-diff-window-config nil)
-
-(defun eshell-diff-quit ()
-  "Restore the window configuration previous to diff'ing."
-  (interactive)
-  (if eshell-diff-window-config
-      (set-window-configuration eshell-diff-window-config)))
-
 (defun eshell-nil-blank-string (string)
   "Return STRING, or nil if STRING contains only blank characters."
   (cond
@@ -1028,8 +1020,7 @@ Show wall-clock time elapsed during execution of COMMAND.")
          (throw 'eshell-replace-command
                 (eshell-parse-command "*diff" orig-args)))
       (let ((old (car (last args 2)))
-           (new (car (last args)))
-           (config (current-window-configuration)))
+            (new (car (last args))))
        (if (= (length args) 2)
            (setq args nil)
          (setcdr (last args 3) nil))
@@ -1041,18 +1032,6 @@ Show wall-clock time elapsed during execution of COMMAND.")
              (error
               (throw 'eshell-replace-command
                      (eshell-parse-command "*diff" orig-args))))
-         (when (fboundp 'diff-mode)
-           (add-hook
-            'compilation-finish-functions
-            (lambda (buff _msg)
-               (with-current-buffer buff
-                 (diff-mode)
-                  (setq-local eshell-diff-window-config config)
-                 (local-set-key [?q] #'eshell-diff-quit)
-                 (if (fboundp 'turn-on-font-lock-if-enabled)
-                     (turn-on-font-lock-if-enabled))
-                 (goto-char (point-min))))
-            nil t))
          (pop-to-buffer (current-buffer))))))
   nil)
 
@@ -1088,6 +1067,9 @@ Show wall-clock time elapsed during execution of COMMAND.")
 (put 'eshell/occur 'eshell-no-numeric-conversions t)
 
 (define-obsolete-function-alias 'nil-blank-string #'eshell-nil-blank-string "29.1")
+(defvar eshell-diff-window-config nil)
+(make-obsolete-variable 'eshell-diff-window-config "no longer used." "30.1")
+(define-obsolete-function-alias 'eshell-diff-quit #'ignore "30.1")
 
 (provide 'em-unix)