fix for history-search-backward after previous-history clearing the undo list

lib/readline/histlib.h

@@ -1,6 +1,6 @@
 /* histlib.h -- internal definitions for the history library. */
 
-/* Copyright (C) 1989-2009,2021 Free Software Foundation, Inc.
+/* Copyright (C) 1989-2009,2021-2022 Free Software Foundation, Inc.
 
    This file contains the GNU History Library (History), a set of
    routines for managing the text of previously typed lines.
@@ -84,6 +84,7 @@ extern int _hs_history_patsearch (const char *, int, int);
 
 /* history.c */
 extern void _hs_replace_history_data (int, histdata_t *, histdata_t *);
+extern int _hs_at_end_of_history (void);
 
 /* histfile.c */
 extern void _hs_append_history_line (int, const char *);

lib/readline/history.c

@@ -165,6 +165,13 @@ history_set_pos (int pos)
   history_offset = pos;
   return (1);
 }
+
+/* Are we currently at the end of the history list? */
+int
+_hs_at_end_of_history (void)
+{
+  return (the_history == 0 || history_offset == history_length);
+}
  
 /* Return the current history array.  The caller has to be careful, since this
    is the actual array of data, and could be bashed or made corrupt easily.

lib/readline/misc.c

@@ -388,17 +388,23 @@ _rl_free_saved_history_line (void)
     {
       if (rl_undo_list && rl_undo_list == (UNDO_LIST *)_rl_saved_line_for_history->data)
 	rl_undo_list = 0;
+
       /* Have to free this separately because _rl_free_history entry can't:
 	 it doesn't know whether or not this has application data. Only the
 	 callers that know this is _rl_saved_line_for_history can know that
 	 it's an undo list. */
+#if defined (HISTORY_SEARCH_SETS_HISTPOS)
       if (_rl_saved_line_for_history->data)
 	{
 	  orig = rl_undo_list;
-	  rl_undo_list = _rl_saved_line_for_history->data;
+	  rl_undo_list = (UNDO_LIST *)_rl_saved_line_for_history->data;
 	  rl_free_undo_list ();
 	  rl_undo_list = orig;
 	}
+#else
+      if (_rl_saved_line_for_history->data)
+	_rl_free_undo_list ((UNDO_LIST *)_rl_saved_line_for_history->data);
+#endif
       _rl_free_history_entry (_rl_saved_line_for_history);
       _rl_saved_line_for_history = (HIST_ENTRY *)NULL;
     }

lib/readline/readline.c

@@ -492,7 +492,7 @@ readline_internal_teardown (int eof)
   /* We don't want to do this if we executed functions that call
      history_set_pos to set the history offset to the line containing the
      non-incremental search string. */
-#if HISTORY_SEARCH_SETS_HISTPOS
+#if defined (HISTORY_SEARCH_SETS_HISTPOS)
   if (entry && rl_undo_list && _rl_history_search_pos != where_history ())
 #else
   if (entry && rl_undo_list)

lib/readline/search.c

@@ -84,6 +84,15 @@ static int _rl_nsearch_dispatch (_rl_search_cxt *, int);
 static void
 make_history_line_current (HIST_ENTRY *entry)
 {
+#if !defined (HISTORY_SEARCH_SETS_HISTPOS)
+  UNDO_LIST *xlist;
+
+  xlist = _rl_saved_line_for_history ? (UNDO_LIST *)_rl_saved_line_for_history->data : 0;
+  /* At this point, rl_undo_list points to a private search string list. */
+  if (rl_undo_list && rl_undo_list != (UNDO_LIST *)entry->data && rl_undo_list != xlist)
+    rl_free_undo_list ();
+#endif
+
   /* Now we create a new undo list with a single insert for this text.
      WE DON'T CHANGE THE ORIGINAL HISTORY ENTRY UNDO LIST */
   _rl_replace_text (entry->line, 0, rl_end);
@@ -97,7 +106,16 @@ make_history_line_current (HIST_ENTRY *entry)
     rl_free_undo_list ();
 #endif
 
-    /* XXX - free the saved line for history here? */
+#if !defined (HISTORY_SEARCH_SETS_HISTPOS)
+  /* This will need to free the saved undo list associated with the original
+     (pre-search) line buffer.
+     XXX - look at _rl_free_saved_history_line and consider calling it if
+     rl_undo_list != xlist (or calling rl_free_undo list directly on
+     _rl_saved_line_for_history->data) */
+  if (_rl_saved_line_for_history)
+    _rl_free_history_entry (_rl_saved_line_for_history);
+  _rl_saved_line_for_history = (HIST_ENTRY *)NULL;
+#endif
 }
 
 /* Search the history list for STRING starting at absolute history position
@@ -186,8 +204,10 @@ noninc_dosearch (char *string, int dir, int flags)
     history_set_pos (oldpos);
 
   make_history_line_current (entry);
+#if !defined (HISTORY_SEARCH_SETS_HISTPOS)
   /* make_history_line_current used to do this. */
   _rl_free_saved_history_line ();
+#endif
 
   if (_rl_enable_active_region && ((flags & SF_PATTERN) == 0) && ind > 0 && ind < rl_end)
     {
@@ -517,16 +537,21 @@ static int
 rl_history_search_internal (int count, int dir)
 {
   HIST_ENTRY *temp;
+  int ret, oldpos, newcol;
   UNDO_LIST *origlist;
-  int ret, oldpos, newcol, had_saved_line, origpos;
+  int had_saved_line, origpos;
   char *t;
 
+#if defined (HISTORY_SEARCH_SETS_HISTPOS)
   origpos = where_history ();
   had_saved_line = _rl_saved_line_for_history != 0;
   rl_maybe_save_line ();
   /* This will either be restored from the saved line or set from the
      found history line. */
   rl_undo_list = 0;
+#else
+  rl_maybe_save_line ();
+#endif
   temp = (HIST_ENTRY *)NULL;
 
   /* Search COUNT times through the history for a line matching
@@ -581,16 +606,16 @@ rl_history_search_internal (int count, int dir)
   /* Copy the line we found into the current line buffer. */
   make_history_line_current (temp);
 
-  /* Free the saved history line corresponding to the search string */
-  if (had_saved_line == 0)
-    _rl_free_saved_history_line ();
-
-#if HISTORY_SEARCH_SETS_HISTPOS
   /* XXX - can't make this work the way I want it to yet. Too much assumes
      that rl_undo_list corresponds to the current history entry's undo list,
      especially the stuff in maybe_save_line and especially maybe_replace_line.
      Leaving it commented out for now. */
 
+#if defined (HISTORY_SEARCH_SETS_HISTPOS)
+  /* Free the saved history line corresponding to the search string */
+  if (had_saved_line == 0)
+    _rl_free_saved_history_line ();
+
   /* Make sure we set the current history position to the last line found so
      we can do things like operate-and-get-next from here. This is similar to
      how incremental search behaves. */
@@ -644,7 +669,7 @@ rl_history_search_reinit (int flags)
       strncpy (history_search_string + sind, rl_line_buffer, rl_point);
       history_search_string[rl_point + sind] = '\0';
     }
-  _rl_free_saved_history_line ();
+  _rl_free_saved_history_line ();	/* XXX rl_undo_list? */
 }
 
 /* Search forward in the history for the string of characters