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.

2 files changed, 7 insertions, 60 deletions

diff --git a/src/callint.c b/src/callint.c
index 08a8bba4646..fd44494cfee 100644
--- a/src/callint.c
+++ b/src/callint.c
@@ -262,7 +262,7 @@ to the function `interactive' at the top level of the function body.
 See `interactive'.
 
 Optional second arg RECORD-FLAG non-nil
-means unconditionally put this command in the command-history.
+means unconditionally put this command in the variable `command-history'.
 Otherwise, this is done only if an arg is read using the minibuffer.
 
 Optional third arg KEYS, if given, specifies the sequence of events to
@@ -328,18 +328,8 @@ invoke it.  If KEYS is omitted or nil, the return value of
              and turn them into things we can eval.  */
           Lisp_Object values = quotify_args (Fcopy_sequence (specs));
           fix_command (input, values);
-          Lisp_Object this_cmd = Fcons (function, values);
-          if (history_delete_duplicates)
-            Vcommand_history = Fdelete (this_cmd, Vcommand_history);
-          Vcommand_history = Fcons (this_cmd, Vcommand_history);
-
-          /* Don't keep command history around forever.  */
-          if (INTEGERP (Vhistory_length) && XINT (Vhistory_length) > 0)
-            {
-              Lisp_Object teml = Fnthcdr (Vhistory_length, Vcommand_history);
-              if (CONSP (teml))
-                XSETCDR (teml, Qnil);
-            }
+          call4 (intern ("add-to-history"), intern ("command-history"),
+                 Fcons (function, values), Qnil, Qt);
         }
 
       Vthis_command = save_this_command;
@@ -768,15 +758,8 @@ invoke it.  If KEYS is omitted or nil, the return value of
         visargs[i] = (varies[i] > 0
                       ? list1 (intern (callint_argfuns[varies[i]]))
                       : quotify_arg (args[i]));
-      Vcommand_history = Fcons (Flist (nargs - 1, visargs + 1),
-                                Vcommand_history);
-      /* Don't keep command history around forever.  */
-      if (INTEGERP (Vhistory_length) && XINT (Vhistory_length) > 0)
-        {
-          Lisp_Object teml = Fnthcdr (Vhistory_length, Vcommand_history);
-          if (CONSP (teml))
-            XSETCDR (teml, Qnil);
-        }
+      call4 (intern ("add-to-history"), intern ("command-history"),
+             Flist (nargs - 1, visargs + 1), Qnil, Qt);
     }
 
   /* If we used a marker to hold point, mark, or an end of the region,
diff --git a/src/minibuf.c b/src/minibuf.c
index c41958d85f9..e18c99bef28 100644
--- a/src/minibuf.c
+++ b/src/minibuf.c
@@ -702,44 +702,8 @@ read_minibuf (Lisp_Object map, Lisp_Object initial, Lisp_Object prompt,
     histstring = Qnil;
 
   /* Add the value to the appropriate history list, if any.  */
-  if (!NILP (Vhistory_add_new_input)
-      && SYMBOLP (Vminibuffer_history_variable)
-      && !NILP (histstring))
-    {
-      /* If the caller wanted to save the value read on a history list,
-         then do so if the value is not already the front of the list.  */
-
-      /* The value of the history variable must be a cons or nil.  Other
-         values are unacceptable.  We silently ignore these values.  */
-
-      if (NILP (histval)
-          || (CONSP (histval)
-              /* Don't duplicate the most recent entry in the history.  */
-              && (NILP (Fequal (histstring, Fcar (histval))))))
-        {
-          Lisp_Object length;
-
-          if (history_delete_duplicates) Fdelete (histstring, histval);
-          histval = Fcons (histstring, histval);
-          Fset (Vminibuffer_history_variable, histval);
-
-          /* Truncate if requested.  */
-          length = Fget (Vminibuffer_history_variable, Qhistory_length);
-          if (NILP (length)) length = Vhistory_length;
-          if (INTEGERP (length))
-            {
-              if (XINT (length) <= 0)
-                Fset (Vminibuffer_history_variable, Qnil);
-              else
-                {
-                  Lisp_Object temp;
-
-                  temp = Fnthcdr (Fsub1 (length), histval);
-                  if (CONSP (temp)) Fsetcdr (temp, Qnil);
-                }
-            }
-        }
-    }
+  if (! (NILP (Vhistory_add_new_input) || NILP (histstring)))
+    call2 (intern ("add-to-history"), Vminibuffer_history_variable, histstring);
 
   /* If Lisp form desired instead of string, parse it.  */
   if (expflag)