shift-delete to delete current history search match

Popular operating systems support shift-delete to delete the selected item
in an autocompletion widgets.  We already support this in the history pager.
Let's do the same for up-arrow history search.

Related discussion: https://github.com/fish-shell/fish-shell/pull/9515

CHANGELOG.rst

@@ -23,7 +23,7 @@ Notable backwards-incompatible changes
 
 - Fish now decodes keyboard input into human-readable key names.
   To make this for for a wide range of terminals, fish asks terminals to speak several keyboard protocols,
-  including CSI u, XTerm's ``modifyOtherKeys`` and some progressive enhancements from the `kitty keyboard protocol <https://sw.kovidgoyal.net/kitty/keyboard-protocol/>`.
+  including CSI u, XTerm's ``modifyOtherKeys`` and some progressive enhancements from the `kitty keyboard protocol <https://sw.kovidgoyal.net/kitty/keyboard-protocol/>`_.
   Depending on terminal support, this allows to bind a lot more key combinations,
   including arbitrary combinations of modifiers ``ctrl``, ``alt`` and ``shift``.
 
@@ -112,6 +112,7 @@ New or improved bindings
 - Special input functions run from bindings via ``commandline -f`` are now applied immediately instead of after the currently executing binding.
   For example, ``commandline -f yank -f yank-pop`` inserts the last-but-one entry from the kill ring.
 - When the cursor is on a command that resolves to an executable script, :kbd:`Alt-O` will now open that script in your editor (:issue:`10266`).
+- During up-arrow history search, :kbd:`shift-delete` will delete the current search item and move to the next older item. Previously this was only supported in the history pager.
 - Two improvements to the :kbd:`Alt-E` binding which edits the commandline in an external editor:
   - The editor's cursor position is copied back to fish. This is currently supported for Vim and Kakoune.
   - Cursor position synchronization is only supported for a set of known editors. This has been extended by also resolving aliases. For example use ``complete --wraps my-vim vim`` to synchronize cursors when `EDITOR=my-vim`.

doc_src/cmds/bind.rst

@@ -229,7 +229,7 @@ The following special input functions are available:
     invoke the searchable pager on history (incremental search); or if the history pager is already active, search further backwards in time.
 
 ``history-pager-delete``
-    permanently delete the history item selected in the history pager
+    permanently delete the current history item, either from the history pager or from an active up-arrow history search
 
 ``history-search-backward``
     search the history for the previous match

src/history.rs

@@ -1843,6 +1843,12 @@ impl HistorySearch {
         &self.orig_term
     }
 
+    pub fn prepare_to_search_after_deletion(&mut self) {
+        assert!(self.current_index != 0);
+        self.current_index -= 1;
+        self.current_item = None;
+    }
+
     /// Finds the next search result. Returns `true` if one was found.
     pub fn go_to_next_match(&mut self, direction: SearchDirection) -> bool {
         let invalid_index = match direction {

src/reader.rs

@@ -2562,6 +2562,16 @@ impl ReaderData {
                 self.insert_string(EditableLineTag::SearchField, &search_string);
             }
             rl::HistoryPagerDelete => {
+                // Also applies to ordinary history search.
+                if !self.history_search.is_at_end() {
+                    self.history
+                        .remove(self.history_search.current_result().to_owned());
+                    self.history.save();
+                    self.history_search.handle_deletion();
+                    self.update_command_line_from_history_search();
+                    self.inputter.function_set_status(true);
+                    return;
+                }
                 if !self.history_pager_active {
                     self.inputter.function_set_status(false);
                     return;
@@ -4674,6 +4684,7 @@ fn command_ends_history_search(c: ReadlineCmd) -> bool {
             | rl::HistorySearchForward
             | rl::HistoryTokenSearchBackward
             | rl::HistoryTokenSearchForward
+            | rl::HistoryPagerDelete
             | rl::BeginningOfHistory
             | rl::EndOfHistory
             | rl::Repaint

src/reader_history_search.rs

@@ -133,6 +133,14 @@ impl ReaderHistorySearch {
         self.skips.insert(s)
     }
 
+    pub fn handle_deletion(&mut self) {
+        assert!(!self.is_at_end());
+        self.matches.remove(self.match_index);
+        self.match_index -= 1;
+        self.search_mut().prepare_to_search_after_deletion();
+        self.move_backwards();
+    }
+
     /// Reset, beginning a new line or token mode search.
     pub fn reset_to_mode(
         &mut self,

tests/checks/tmux-history-search.fish

@@ -46,11 +46,20 @@ isolated-tmux send-keys Enter
 isolated-tmux capture-pane -p | grep 'prompt 2>'
 isolated-tmux send-keys C-c
 
+isolated-tmux send-keys 'echo 1' Enter 'echo 2' Enter 'echo 3' Enter
+isolated-tmux send-keys C-l echo Up
+isolated-tmux send-keys echo M-d
+tmux-sleep
+isolated-tmux capture-pane -p
+#CHECK: prompt 5> echo 2
+isolated-tmux send-keys C-c
+tmux-sleep
+
 isolated-tmux send-keys "echo sdifjsdoifjsdoifj" Enter
 tmux-sleep
-isolated-tmux capture-pane -p | grep "^sdifjsdoifjsdoifj\|prompt 3>"
+isolated-tmux capture-pane -p | grep "^sdifjsdoifjsdoifj\|prompt 6>"
 # CHECK: sdifjsdoifjsdoifj
-# CHECK: prompt 3>
+# CHECK: prompt 6>
 isolated-tmux send-keys C-e C-u C-r
 tmux-sleep
 isolated-tmux send-keys "echo sdifjsdoifjsdoifj"
@@ -61,6 +70,6 @@ isolated-tmux capture-pane -p | grep "(no matches)"
 # CHECK: (no matches)
 isolated-tmux send-keys Enter C-e C-u "echo foo" Enter
 tmux-sleep
-isolated-tmux capture-pane -p | grep "^foo\|prompt 4>"
+isolated-tmux capture-pane -p | grep "^foo\|prompt 7>"
 # CHECK: foo
-# CHECK: prompt 4>
+# CHECK: prompt 7>