tui/flush_buf: Don't toggle cursor when called from out() #5436

unibi_format() calls out() multiple times for a given format string.
When data->buf fills up during this process, flush_buf() gets called,
which possibly calls unibi_out() again to toggle the cursor visibility.
However, if we were halfway through outputting an escape sequence, doing
this will clobber it, resulting in junk being displayed.

Fix this by not toggling the cursor visibility when draining a full
buffer in out().

1 files changed, 6 insertions, 6 deletions

diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index 04b5868d2c..f03d8b87fa 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -174,7 +174,7 @@ static void terminfo_stop(UI *ui)
   unibi_out(ui, data->unibi_ext.disable_bracketed_paste);
   // Disable focus reporting
   unibi_out(ui, data->unibi_ext.disable_focus_reporting);
-  flush_buf(ui);
+  flush_buf(ui, true);
   uv_tty_reset_mode();
   uv_close((uv_handle_t *)&data->output_handle, NULL);
   uv_run(&data->write_loop, UV_RUN_DEFAULT);
@@ -601,7 +601,7 @@ static void tui_flush(UI *ui)
 
   unibi_goto(ui, grid->row, grid->col);
 
-  flush_buf(ui);
+  flush_buf(ui, true);
 }
 
 static void suspend_event(void **argv)
@@ -774,7 +774,7 @@ static void out(void *ctx, const char *str, size_t len)
   size_t available = data->bufsize - data->bufpos;
 
   if (len > available) {
-    flush_buf(ui);
+    flush_buf(ui, false);
   }
 
   memcpy(data->buf + data->bufpos, str, len);
@@ -910,13 +910,13 @@ end:
   unibi_set_if_empty(ut, unibi_clr_eos, "\x1b[J");
 }
 
-static void flush_buf(UI *ui)
+static void flush_buf(UI *ui, bool toggle_cursor)
 {
   uv_write_t req;
   uv_buf_t buf;
   TUIData *data = ui->data;
 
-  if (!data->busy) {
+  if (toggle_cursor && !data->busy) {
     // not busy and the cursor is invisible(see below). Append a "cursor
     // normal" command to the end of the buffer.
     data->bufsize += CNORM_COMMAND_MAX_SIZE;
@@ -930,7 +930,7 @@ static void flush_buf(UI *ui)
   uv_run(&data->write_loop, UV_RUN_DEFAULT);
   data->bufpos = 0;
 
-  if (!data->busy) {
+  if (toggle_cursor && !data->busy) {
     // not busy and cursor is visible(see above), append a "cursor invisible"
     // command to the beginning of the buffer for the next flush
     unibi_out(ui, unibi_cursor_invisible);