feat(extmarks): support hl_mode "combine" for inline virt_text (#24099)

2 files changed, 12 insertions, 5 deletions

diff --git a/src/nvim/api/extmark.c b/src/nvim/api/extmark.c
index d79cbf7508..a101e1bbf1 100644
--- a/src/nvim/api/extmark.c
+++ b/src/nvim/api/extmark.c
@@ -478,7 +478,7 @@ Array nvim_buf_get_extmarks(Buffer buffer, Integer ns_id, Object start, Object e
 ///                              shifting the underlying text.
 ///                 - "right_align": display right aligned in the window.
 ///                 - "inline": display at the specified column, and
-///                              shift the buffer text to the right as needed
+///                             shift the buffer text to the right as needed
 ///               - virt_text_win_col : position the virtual text at a fixed
 ///                                     window column (starting from the first
 ///                                     text column)
@@ -490,10 +490,10 @@ Array nvim_buf_get_extmarks(Buffer buffer, Integer ns_id, Object start, Object e
 ///                           highlights of the text. Currently only affects
 ///                           virt_text highlights, but might affect `hl_group`
 ///                           in later versions.
-///                 - "replace": only show the virt_text color. This is the
-///                              default
-///                 - "combine": combine with background text color
+///                 - "replace": only show the virt_text color. This is the default.
+///                 - "combine": combine with background text color.
 ///                 - "blend": blend with background text color.
+///                            Not supported for "inline" virt_text.
 ///
 ///               - virt_lines : virtual lines to add next to this mark
 ///                   This should be an array over lines, where each line in
@@ -730,6 +730,11 @@ Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id, Integer line, Integer
     } else if (strequal("combine", str.data)) {
       decor.hl_mode = kHlModeCombine;
     } else if (strequal("blend", str.data)) {
+      if (decor.virt_text_pos == kVTInline) {
+        VALIDATE(false, "%s", "cannot use 'blend' hl_mode with inline virtual text", {
+          goto error;
+        });
+      }
       decor.hl_mode = kHlModeBlend;
     } else {
       VALIDATE_S(false, "hl_mode", str.data, {
diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 34d15d85c3..9728804ed7 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -128,6 +128,7 @@ typedef struct {
 
   VirtText virt_inline;
   size_t virt_inline_i;
+  HlMode virt_inline_hl_mode;
 
   bool reset_extra_attr;
 
@@ -886,6 +887,7 @@ static void handle_inline_virtual_text(win_T *wp, winlinevars_T *wlv, ptrdiff_t
         }
         if (item->draw_col >= -1 && item->start_col == v) {
           wlv->virt_inline = item->decor.virt_text;
+          wlv->virt_inline_hl_mode = item->decor.hl_mode;
           item->draw_col = INT_MIN;
           break;
         }
@@ -1798,7 +1800,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
 
         if (!has_fold) {
           handle_inline_virtual_text(wp, &wlv, v);
-          if (wlv.n_extra > 0) {
+          if (wlv.n_extra > 0 && wlv.virt_inline_hl_mode <= kHlModeReplace) {
             // restore search_attr and area_attr when n_extra is down to zero
             // TODO(bfredl): this is ugly as fuck. look if we can do this some other way.
             saved_search_attr = search_attr;