Eshell: Ignore all duplicates in history

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

@@ -193,12 +193,13 @@
 
 ;;; History
 ;;; Filter out space-beginning commands from history.
-;;; TODO: history/command hook: trim surrounding space.  Check `eshell-rewrite-command-hook'.
-;;; TODO: history: do not save failed commands to file.
-;;; TODO: history: do not store duplicates.  Push unique command to front of the list.
+;;; TODO: history/command hook: trim spaces.  Check `eshell-rewrite-command-hook'.
+;;; TODO: history: do not save failed Eshell commands (See `eshell-last-command-status')
+;;; Eshell commands always return 0.
 (setq eshell-input-filter
       (lambda (str)
-        (not (or (string= "" str)
+        (not (or (/= eshell-last-command-status 0)
+                 (string= "" str)
                  (string-prefix-p " " str)))))
 
 ;;; Shared history.

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

@@ -214,4 +214,19 @@ See `eshell-prompt-regexp'."
    (when face
      (put-text-property beg end 'face face))))
 
+;;; REVIEW: Ignore dups in the entire ring, not just the last entry.
+;;; Reported upstream, see #30466.
+(defun eshell-add-input-to-history (input)
+  "Add the string INPUT to the history ring.
+Input is entered into the input history ring, if the value of
+variable `eshell-input-filter' returns non-nil when called on the
+input."
+  (when (funcall eshell-input-filter input)
+    (when eshell-hist-ignoredups
+      (ring-remove eshell-history-ring
+                   (ring-member eshell-history-ring input)))
+    (eshell-put-history input))
+  (setq eshell-save-history-index eshell-history-index)
+  (setq eshell-history-index nil))
+
 (provide 'patch-eshell)