Fix regression causing scrollback-push to not clear text below cursor

If a child program crashes with some text rendered below the cursor,
we fail to clear that text. For example run vim, "pkill -9 vim" and
observe that scrollback-push fails to clean up the leftover text.
Fix that.

CHANGELOG.rst

@@ -27,7 +27,7 @@ New or improved bindings
 ^^^^^^^^^^^^^^^^^^^^^^^^
 - :kbd:`ctrl-z` (undo) after executing a command will restore the previous cursor position instead of placing the cursor at the end of the command line.
 - The OSC 133 prompt marking feature has learned about kitty's ``click_events=1`` flag, which allows moving fish's cursor by clicking.
-- :kbd:`ctrl-l` no longer clears the screen but only pushes to the terminal's scrollback all text above the prompt (via a new special input function ``scrollback-push``).
+- :kbd:`ctrl-l` now pushes all text located above the prompt to the terminal's scrollback, before clearing and redrawing the screen (via a new special input function ``scrollback-push``).
   This feature depends on the terminal advertising via XTGETTCAP support for the ``indn`` and ``cuu`` terminfo capabilities,
   and on the terminal supporting Synchronized Output (which is used by fish to detect features).
   If any is missing, the binding falls back to ``clear-screen``.

share/functions/__fish_shared_key_bindings.fish

@@ -66,7 +66,7 @@ function __fish_shared_key_bindings -d "Bindings shared between emacs and vi mod
     bind --preset $argv alt-l __fish_list_current_token
     bind --preset $argv alt-o __fish_preview_current_file
     bind --preset $argv alt-w __fish_whatis_current_token
-    bind --preset $argv ctrl-l scrollback-push repaint
+    bind --preset $argv ctrl-l scrollback-push clear-screen
     bind --preset $argv ctrl-c clear-commandline
     bind --preset $argv ctrl-u backward-kill-line
     bind --preset $argv ctrl-k kill-line

src/reader.rs

@@ -3742,7 +3742,6 @@ impl<'a> Reader<'a> {
             }
             rl::ScrollbackPush => {
                 if !SCROLL_FORWARD_SUPPORTED.load() || !CURSOR_UP_SUPPORTED.load() {
-                    self.clear_screen_and_repaint();
                     return;
                 }
                 match self.cursor_position_wait() {
@@ -3750,7 +3749,7 @@ impl<'a> Reader<'a> {
                         &mut Outputter::stdoutput().borrow_mut(),
                         CursorPositionWait::Blocking(CursorPositionBlockingWait::ScrollbackPush),
                     ),
-                    CursorPositionWait::InitialFeatureProbe => self.clear_screen_and_repaint(),
+                    CursorPositionWait::InitialFeatureProbe => (),
                     CursorPositionWait::Blocking(_) => {
                         // TODO: re-queue it I guess.
                         FLOG!(

tests/checks/tmux-scrollback.fish

@@ -2,7 +2,7 @@
 #REQUIRES: command -v tmux
 
 isolated-tmux-start
-isolated-tmux send-keys 'bind ctrl-g "commandline -f scrollback-push scrollback-push"' Enter C-g
+isolated-tmux send-keys 'bind ctrl-g "commandline -f scrollback-push scrollback-push clear-screen"' Enter C-g
 tmux-sleep
 isolated-tmux capture-pane -p
 # CHECK: prompt 1>