fix(ui): propagate line wrapping state on grid_line events

This fixes the TUI's line-wrapping behavior, which was broken with the
migration to the msgpack-based UI protocol (see
https://github.com/neovim/neovim/issues/7369#issuecomment-1571812273).

5 files changed, 24 insertions, 11 deletions

diff --git a/src/nvim/api/ui.c b/src/nvim/api/ui.c
index e98c589189..861ce100cd 100644
--- a/src/nvim/api/ui.c
+++ b/src/nvim/api/ui.c
@@ -73,6 +73,11 @@ static void mpack_uint(char **buf, uint32_t val)
   }
 }
 
+static void mpack_bool(char **buf, bool val)
+{
+  mpack_w(buf, 0xc2 | val);
+}
+
 static void mpack_array(char **buf, uint32_t len)
 {
   if (len < 0x10) {
@@ -809,7 +814,7 @@ void remote_ui_raw_line(UI *ui, Integer grid, Integer row, Integer startcol, Int
     data->ncalls++;
 
     char **buf = &data->buf_wptr;
-    mpack_array(buf, 4);
+    mpack_array(buf, 5);
     mpack_uint(buf, (uint32_t)grid);
     mpack_uint(buf, (uint32_t)row);
     mpack_uint(buf, (uint32_t)startcol);
@@ -823,17 +828,20 @@ void remote_ui_raw_line(UI *ui, Integer grid, Integer row, Integer startcol, Int
       repeat++;
       if (i == ncells - 1 || attrs[i] != attrs[i + 1]
           || strcmp(chunk[i], chunk[i + 1]) != 0) {
-        if (UI_BUF_SIZE - BUF_POS(data) < 2 * (1 + 2 + sizeof(schar_T) + 5 + 5)) {
+        if (UI_BUF_SIZE - BUF_POS(data) < 2 * (1 + 2 + sizeof(schar_T) + 5 + 5) + 1) {
           // close to overflowing the redraw buffer. finish this event,
           // flush, and start a new "grid_line" event at the current position.
           // For simplicity leave place for the final "clear" element
           // as well, hence the factor of 2 in the check.
           mpack_w2(&lenpos, nelem);
+
+          // We only ever set the wrap field on the final "grid_line" event for the line.
+          mpack_bool(buf, false);
           remote_ui_flush_buf(ui);
 
           prepare_call(ui, "grid_line");
           data->ncalls++;
-          mpack_array(buf, 4);
+          mpack_array(buf, 5);
           mpack_uint(buf, (uint32_t)grid);
           mpack_uint(buf, (uint32_t)row);
           mpack_uint(buf, (uint32_t)startcol + (uint32_t)i - repeat + 1);
@@ -865,9 +873,10 @@ void remote_ui_raw_line(UI *ui, Integer grid, Integer row, Integer startcol, Int
       mpack_uint(buf, (uint32_t)(clearcol - endcol));
     }
     mpack_w2(&lenpos, nelem);
+    mpack_bool(buf, flags & kLineFlagWrap);
 
     if (data->ncells_pending > 500) {
-      // pass of cells to UI to let it start processing them
+      // pass off cells to UI to let it start processing them
       remote_ui_flush_buf(ui);
     }
   } else {
diff --git a/src/nvim/api/ui_events.in.h b/src/nvim/api/ui_events.in.h
index b93f521ca3..fc70215352 100644
--- a/src/nvim/api/ui_events.in.h
+++ b/src/nvim/api/ui_events.in.h
@@ -82,7 +82,7 @@ void grid_clear(Integer grid)
   FUNC_API_SINCE(5) FUNC_API_REMOTE_IMPL;
 void grid_cursor_goto(Integer grid, Integer row, Integer col)
   FUNC_API_SINCE(5) FUNC_API_REMOTE_IMPL FUNC_API_COMPOSITOR_IMPL;
-void grid_line(Integer grid, Integer row, Integer col_start, Array data)
+void grid_line(Integer grid, Integer row, Integer col_start, Array data, Boolean wrap)
   FUNC_API_SINCE(5) FUNC_API_REMOTE_ONLY FUNC_API_CLIENT_IMPL;
 void grid_scroll(Integer grid, Integer top, Integer bot, Integer left, Integer right, Integer rows,
                  Integer cols)
diff --git a/src/nvim/grid_defs.h b/src/nvim/grid_defs.h
index 830c74e86d..aae61cc719 100644
--- a/src/nvim/grid_defs.h
+++ b/src/nvim/grid_defs.h
@@ -117,6 +117,7 @@ typedef struct {
   int coloff;
   int cur_attr;
   int clear_width;
+  bool wrap;
 } GridLineEvent;
 
 #endif  // NVIM_GRID_DEFS_H
diff --git a/src/nvim/msgpack_rpc/unpacker.c b/src/nvim/msgpack_rpc/unpacker.c
index 25edf2e21d..4128f91b6e 100644
--- a/src/nvim/msgpack_rpc/unpacker.c
+++ b/src/nvim/msgpack_rpc/unpacker.c
@@ -441,7 +441,7 @@ redo:
   case 14:
     NEXT_TYPE(tok, MPACK_TOKEN_ARRAY);
     int eventarrsize = (int)tok.length;
-    if (eventarrsize != 4) {
+    if (eventarrsize != 5) {
       p->state = -1;
       return false;
     }
@@ -509,11 +509,16 @@ redo:
     }
 
     g->icell++;
-    p->read_ptr = data;
-    p->read_size = size;
     if (g->icell == g->ncells) {
+      NEXT_TYPE(tok, MPACK_TOKEN_BOOLEAN);
+      g->wrap = mpack_unpack_boolean(tok);
+      p->read_ptr = data;
+      p->read_size = size;
       return true;
     }
+
+    p->read_ptr = data;
+    p->read_size = size;
     goto redo;
 
   case 12:
diff --git a/src/nvim/ui_client.c b/src/nvim/ui_client.c
index 1918b0b800..9395ff2f1e 100644
--- a/src/nvim/ui_client.c
+++ b/src/nvim/ui_client.c
@@ -210,9 +210,7 @@ void ui_client_event_raw_line(GridLineEvent *g)
   int grid = g->args[0], row = g->args[1], startcol = g->args[2];
   Integer endcol = startcol + g->coloff;
   Integer clearcol = endcol + g->clear_width;
-
-  // TODO(hlpr98): Accommodate other LineFlags when included in grid_line
-  LineFlags lineflags = 0;
+  LineFlags lineflags = g->wrap ? kLineFlagWrap : 0;
 
   tui_raw_line(tui, grid, row, startcol, endcol, clearcol, g->cur_attr, lineflags,
                (const schar_T *)grid_line_buf_char, grid_line_buf_attr);