Fix off-by-one history pruning (bug#31211)

* lisp/subr.el (add-to-history): Clarify docstring.
Protect against negative history-length and unnecessary variable
modification, as per read_minibuf.

* lisp/ido.el (ido-record-command):
* lisp/international/mule-cmds.el (deactivate-input-method):
(set-language-environment-input-method):
* lisp/isearch.el (isearch-done):
* lisp/minibuffer.el (read-file-name-default):
* lisp/net/eww.el (eww-save-history):
* lisp/simple.el (edit-and-eval-command, repeat-complex-command):
(command-execute, kill-new, push-mark):
* src/callint.c (Fcall_interactively):
* src/minibuf.c (read_minibuf): Delegate to add-to-history.

* test/lisp/simple-tests.el (command-execute-prune-command-history):
* test/src/callint-tests.el
(call-interactively-prune-command-history): New tests.

1 files changed, 3 insertions, 7 deletions

diff --git a/lisp/net/eww.el b/lisp/net/eww.el
index e74f661ac75..97fdabd72bd 100644
--- a/lisp/net/eww.el
+++ b/lisp/net/eww.el
@@ -1813,13 +1813,9 @@ If CHARSET is nil then use UTF-8."
 (defun eww-save-history ()
   (plist-put eww-data :point (point))
   (plist-put eww-data :text (buffer-string))
-  (push eww-data eww-history)
-  (setq eww-data (list :title ""))
-  ;; Don't let the history grow infinitely.  We store quite a lot of
-  ;; data per page.
-  (when-let* ((tail (and eww-history-limit
-                         (nthcdr eww-history-limit eww-history))))
-    (setcdr tail nil)))
+  (let ((history-delete-duplicates nil))
+    (add-to-history 'eww-history eww-data eww-history-limit t))
+  (setq eww-data (list :title "")))
 
 (defvar eww-current-buffer)