fix(terminal): avoid more `busy_start` lacking `busy_stop` (#32509)

Problem: after #32458, it may still be possible for `busy_start` UI events to be
emitted without matching `busy_stop`s in the terminal.

Solution: do `terminal_enter`'s cursor visibility check immediately after
setting/restoring State so it occurs before events. This ensures that if pending
escape sequences are processed while in `terminal_enter`, the cursor's initial
visibility is set before `is_focused` is checked by `term_settermprop`.

As a result, we can move the call to `showmode` back to where it was originally.

2 files changed, 35 insertions, 9 deletions

diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index 61b55f71de..47630ddea9 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -662,6 +662,10 @@ bool terminal_enter(void)
   State = MODE_TERMINAL;
   mapped_ctrl_c |= MODE_TERMINAL;  // Always map CTRL-C to avoid interrupt.
   RedrawingDisabled = false;
+  if (!s->term->cursor.visible) {
+    // Hide cursor if it should be hidden. Do so right after setting State, before events.
+    ui_busy_start();
+  }
 
   // Disable these options in terminal-mode. They are nonsense because cursor is
   // placed at end of buffer to "follow" output. #11072
@@ -693,14 +697,10 @@ bool terminal_enter(void)
   refresh_cursor(s->term);
 
   adjust_topline(s->term, buf, 0);  // scroll to end
+  showmode();
   curwin->w_redr_status = true;  // For mode() in statusline. #8323
   redraw_custom_title_later();
-  if (!s->term->cursor.visible) {
-    // Hide cursor if it should be hidden
-    ui_busy_start();
-  }
   ui_cursor_shape();
-  showmode();
   apply_autocmds(EVENT_TERMENTER, NULL, NULL, false, curbuf);
   may_trigger_modechanged();
 
@@ -716,6 +716,11 @@ bool terminal_enter(void)
   }
   State = save_state;
   RedrawingDisabled = s->save_rd;
+  if (!s->term->cursor.visible) {
+    // If cursor was hidden, show it again. Do so right after restoring State, before events.
+    ui_busy_stop();
+  }
+
   apply_autocmds(EVENT_TERMLEAVE, NULL, NULL, false, curbuf);
 
   // Restore the terminal cursor to what is set in 'guicursor'
@@ -746,10 +751,6 @@ bool terminal_enter(void)
   } else {
     unshowmode(true);
   }
-  if (!s->term->cursor.visible) {
-    // If cursor was hidden, show it again
-    ui_busy_stop();
-  }
   ui_cursor_shape();
   if (s->close) {
     bool wipe = s->term->buf_handle != 0;
diff --git a/test/functional/terminal/cursor_spec.lua b/test/functional/terminal/cursor_spec.lua
index a824893ce3..8ebad14f15 100644
--- a/test/functional/terminal/cursor_spec.lua
+++ b/test/functional/terminal/cursor_spec.lua
@@ -382,6 +382,31 @@ describe(':terminal cursor', function()
       ^                                                  |
                                                         |*5
     ]])
+
+    feed('i')
+    screen:expect([[
+      tty ready                                         |
+                                                        |*5
+      {3:-- TERMINAL --}                                    |
+    ]])
+
+    -- Cursor currently hidden; request to show it while in a TermLeave autocmd.
+    -- Process events (via :sleep) to handle the escape sequence immediately.
+    command([[autocmd TermLeave * ++once call chansend(b:terminal_job_id, "\e[?25h") | sleep 1m]])
+    feed([[<C-\><C-N>]]) -- Exit terminal mode
+    screen:expect([[
+      tty ready                                         |
+      ^                                                  |
+                                                        |*5
+    ]])
+
+    feed('i')
+    screen:expect([[
+      tty ready                                         |
+      ^                                                  |
+                                                        |*4
+      {3:-- TERMINAL --}                                    |
+    ]])
   end)
 end)