Save the screen status more often

The fix for #3481 caused us to save the screen status after external
commands were run, fixing an unnecessary abandon-line when switching
modes. But we may also run commands not directly as part of a binding,
but instead via an on-variable event, e.g. for fish_bind_mode.

Extend this fix to all bindings, guarded by changes to exec_count. Now
any time an external command runs as part of a binding we should pick up
changes to the tty and not abandon the line.

Fixes #3481 again.

CHANGELOG.rst

@@ -95,7 +95,7 @@ Interactive improvements
 - ``time`` now emits an error if used after the first command in a pipeline (:issue:`8841`).
 - ``fish_add_path`` now prints a message for skipped non-existent paths when using the ``-v`` flag (:issue:`8884`).
 - Since fish 3.2.0, pressing :kbd:`Control-D` while a command is running would end up inserting a space into the next commandline, which has been fixed (:issue:`8871`).
-- A bug that caused multi-line prompts to be moved down a line when switching between insert and normal mode has been fixed (:issue:`3481`).
+- A bug that caused multi-line prompts to be moved down a line when pasting or switching modes has been fixed (:issue:`3481`).
 - The web-based configuration system no longer strips too many quotes in the abbreviation display (:issue:`8917`, :issue:`8918`).
 - Fish started with ``--no-config`` will now use the default keybindings (:issue:`8493`)
 - When fish inherits a $USER value that doesn't correspond to the euid, it will now correct it in all cases instead of just when euid is 0 (:issue:`8879`, :issue:`8583`).

src/reader.cpp

@@ -738,6 +738,9 @@ class reader_data_t : public std::enable_shared_from_this<reader_data_t> {
     parser_t &parser() { return *parser_ref; }
     const parser_t &parser() const { return *parser_ref; }
 
+    /// Convenience cover over exec_count().
+    uint64_t exec_count() const { return parser().libdata().exec_count; }
+
     reader_data_t(std::shared_ptr<parser_t> parser, std::shared_ptr<history_t> hist,
                   reader_config_t &&conf)
         : conf(std::move(conf)),
@@ -3079,10 +3082,6 @@ void reader_data_t::run_input_command_scripts(const wcstring_list_t &cmds) {
         wperror(L"tcsetattr");
     }
     termsize_container_t::shared().invalidate_tty();
-
-    // The input command scripts may have changed our tty - ignore any such changes.
-    // See #3481.
-    screen.save_status();
 }
 
 /// Read normal characters, inserting them into the command line.
@@ -3098,6 +3097,10 @@ maybe_t<char_event_t> reader_data_t::read_normal_chars(readline_loop_state_t &rl
     };
     command_handler_t empty_handler = {};
 
+    // We repaint our prompt if fstat reports the tty as having changed.
+    // But don't react to tty changes that we initiated, because of commands or
+    // on-variable events (e.g. for fish_bind_mode). See #3481.
+    uint64_t last_exec_count = exec_count();
     while (accumulated_chars.size() < limit) {
         bool allow_commands = (accumulated_chars.empty());
         auto evt = inputter.read_char(allow_commands ? normal_handler : empty_handler);
@@ -3111,6 +3114,11 @@ maybe_t<char_event_t> reader_data_t::read_normal_chars(readline_loop_state_t &rl
         } else {
             accumulated_chars.push_back(evt.get_char());
         }
+
+        if (last_exec_count != exec_count()) {
+            last_exec_count = exec_count();
+            screen.save_status();
+        }
     }
 
     if (!accumulated_chars.empty()) {
@@ -3125,6 +3133,12 @@ maybe_t<char_event_t> reader_data_t::read_normal_chars(readline_loop_state_t &rl
         // Since we handled a normal character, we don't have a last command.
         rls.last_cmd.reset();
     }
+
+    if (last_exec_count != exec_count()) {
+        last_exec_count = exec_count();
+        screen.save_status();
+    }
+
     return event_needing_handling;
 }