Eshell: Fix trimming of trailing whitespaces

.emacs.d/lisp/init-eshell.el

@@ -210,14 +210,6 @@
               ;; Filter out space-beginning commands from history.
               (string-prefix-p " " str)))))
 
-(defun ambrevar/eshell-delete-trailing-whitespace (last-output-end point)
-  "Delete trailing whitespace in Eshell command.
-This is useful to avoid dumb duplicates in history."
-  (save-mark-and-excursion
-    (goto-char (point-max))
-    (delete-trailing-whitespace)))
-(add-hook 'eshell-expand-input-functions 'ambrevar/eshell-delete-trailing-whitespace)
-
 ;;; Shared history.
 (defvar ambrevar/eshell-history-global-ring nil
   "The history ring shared across Eshell sessions.")

.emacs.d/lisp/patch-eshell-26.el

@@ -5,6 +5,11 @@
 Input is entered into the input history ring, if the value of
 variable `eshell-input-filter' returns non-nil when called on the
 input."
+  (require 'subr-x)
+  ;; TODO: Report this trick, so that "ls" and "ls " don't both get added to the
+  ;; history.  Doing this from eshell-expand-input-functions breaks Eshell
+  ;; because the input is not expected to be modified.
+  (setq input (string-trim-right input))
   (when (funcall eshell-input-filter input)
     (when eshell-hist-ignoredups
       (ring-remove eshell-history-ring