4 files changed, 41 insertions, 17 deletions

diff --git a/src/nvim/cursor_shape.c b/src/nvim/cursor_shape.c
index b45e7002f7..cf79005a37 100644
--- a/src/nvim/cursor_shape.c
+++ b/src/nvim/cursor_shape.c
@@ -64,6 +64,9 @@ Array mode_style_array(void)
       PUT(dic, "blinkoff", INTEGER_OBJ(cur->blinkoff));
       PUT(dic, "hl_id", INTEGER_OBJ(cur->id));
       PUT(dic, "id_lm", INTEGER_OBJ(cur->id_lm));
+      PUT(dic, "attr_id", INTEGER_OBJ(cur->id ? syn_id2attr(cur->id) : 0));
+      PUT(dic, "attr_id_lm", INTEGER_OBJ(cur->id_lm ? syn_id2attr(cur->id_lm)
+                                                    : 0));
     }
     PUT(dic, "name", STRING_OBJ(cstr_to_string(cur->full_name)));
     PUT(dic, "short_name", STRING_OBJ(cstr_to_string(cur->name)));
@@ -258,15 +261,30 @@ char_u *parse_shape_opt(int what)
 /// @return -1 in case of failure, else the matching SHAPE_ID* integer
 int cursor_mode_str2int(const char *mode)
 {
-  for (int current_mode = 0; current_mode < SHAPE_IDX_COUNT; current_mode++) {
-    if (strcmp(shape_table[current_mode].full_name, mode) == 0) {
-      return current_mode;
+  for (int mode_idx = 0; mode_idx < SHAPE_IDX_COUNT; mode_idx++) {
+    if (strcmp(shape_table[mode_idx].full_name, mode) == 0) {
+      return mode_idx;
     }
   }
   WLOG("Unknown mode %s", mode);
   return -1;
 }
 
+/// Check if a syntax id is used as a cursor style.
+bool cursor_mode_uses_syn_id(int syn_id)
+{
+  if (*p_guicursor == NUL) {
+    return false;
+  }
+  for (int mode_idx = 0; mode_idx < SHAPE_IDX_COUNT; mode_idx++) {
+    if (shape_table[mode_idx].id == syn_id
+        || shape_table[mode_idx].id_lm == syn_id) {
+      return true;
+    }
+  }
+  return false;
+}
+
 
 /// Return the index into shape_table[] for the current mode.
 int cursor_get_mode_idx(void)
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index d7c23742ba..3cb998b805 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -16,6 +16,7 @@
 #include "nvim/ascii.h"
 #include "nvim/syntax.h"
 #include "nvim/charset.h"
+#include "nvim/cursor_shape.h"
 #include "nvim/eval.h"
 #include "nvim/ex_cmds2.h"
 #include "nvim/ex_docmd.h"
@@ -7228,7 +7229,6 @@ static void set_hl_attr(int idx)
   HlAttrs at_en = HLATTRS_INIT;
   struct hl_group     *sgp = HL_TABLE() + idx;
 
-
   at_en.cterm_ae_attr = sgp->sg_cterm;
   at_en.cterm_fg_color = sgp->sg_cterm_fg;
   at_en.cterm_bg_color = sgp->sg_cterm_bg;
@@ -7241,6 +7241,11 @@ static void set_hl_attr(int idx)
   at_en.rgb_sp_color = sgp->sg_rgb_sp_name ? sgp->sg_rgb_sp : -1;
 
   sgp->sg_attr = hl_get_syn_attr(idx+1, at_en);
+
+  // a cursor style uses this syn_id, make sure its atribute is updated.
+  if (cursor_mode_uses_syn_id(idx+1)) {
+    ui_mode_info_set();
+  }
 }
 
 /// Lookup a highlight group name and return its ID.
diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index c010f2e1a2..df14ddf988 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -874,7 +874,7 @@ static cursorentry_T decode_cursor_entry(Dictionary args)
       r.blinkon = (int)value.data.integer;
     } else if (strequal(key, "blinkoff")) {
       r.blinkoff = (int)value.data.integer;
-    } else if (strequal(key, "hl_id")) {
+    } else if (strequal(key, "attr_id")) {
       r.id = (int)value.data.integer;
     }
   }
@@ -942,14 +942,10 @@ static void tui_set_mode(UI *ui, ModeShape mode)
   TUIData *data = ui->data;
   cursorentry_T c = data->cursor_shapes[mode];
 
-  if (c.id != 0 && ui->rgb) {
-    // TODO(bfredl): NOT threadsafe, include attr in cursor_shape already.
-    int attr = syn_id2attr(c.id);
-    if (attr > 0 && attr < (int)kv_size(data->attrs)) {
-      int color = kv_A(data->attrs, attr).rgb_bg_color;
-      UNIBI_SET_NUM_VAR(data->params[0], color);
-      unibi_out_ext(ui, data->unibi_ext.set_cursor_color);
-    }
+  if (c.id != 0 && c.id < (int)kv_size(data->attrs) && ui->rgb) {
+    int color = kv_A(data->attrs, c.id).rgb_bg_color;
+    UNIBI_SET_NUM_VAR(data->params[0], color);
+    unibi_out_ext(ui, data->unibi_ext.set_cursor_color);
   }
 
   int shape;
diff --git a/src/nvim/ui.c b/src/nvim/ui.c
index ef68b804ba..07aa032a50 100644
--- a/src/nvim/ui.c
+++ b/src/nvim/ui.c
@@ -55,6 +55,7 @@ static int row = 0, col = 0;
 static bool pending_cursor_update = false;
 static int busy = 0;
 static int mode_idx = SHAPE_IDX_N;
+static bool pending_mode_info_update = false;
 static bool pending_mode_update = false;
 
 #if MIN_LOG_LEVEL > DEBUG_LOG_LEVEL
@@ -368,10 +369,7 @@ void ui_add_linewrap(int row)
 
 void ui_mode_info_set(void)
 {
-  Array style = mode_style_array();
-  bool enabled = (*p_guicursor != NUL);
-  ui_call_mode_info_set(enabled, style);
-  api_free_array(style);
+  pending_mode_info_update = true;
 }
 
 int ui_current_row(void)
@@ -391,6 +389,13 @@ void ui_flush(void)
     ui_call_grid_cursor_goto(1, row, col);
     pending_cursor_update = false;
   }
+  if (pending_mode_info_update) {
+    Array style = mode_style_array();
+    bool enabled = (*p_guicursor != NUL);
+    ui_call_mode_info_set(enabled, style);
+    api_free_array(style);
+    pending_mode_info_update = false;
+  }
   if (pending_mode_update) {
     char *full_name = shape_table[mode_idx].full_name;
     ui_call_mode_change(cstr_as_string(full_name), mode_idx);