fix(highlight): properly deal with underline mask when listing (#22057)

4 files changed, 17 insertions, 12 deletions

diff --git a/src/nvim/highlight.c b/src/nvim/highlight.c
index 9dab91cc2b..c20eac3c28 100644
--- a/src/nvim/highlight.c
+++ b/src/nvim/highlight.c
@@ -842,14 +842,14 @@ void hlattrs2dict(Dictionary *dict, HlAttrs ae, bool use_rgb)
     PUT_C(hl, "underline", BOOLEAN_OBJ(true));
     break;
 
-  case HL_UNDERDOUBLE:
-    PUT_C(hl, "underdouble", BOOLEAN_OBJ(true));
-    break;
-
   case HL_UNDERCURL:
     PUT_C(hl, "undercurl", BOOLEAN_OBJ(true));
     break;
 
+  case HL_UNDERDOUBLE:
+    PUT_C(hl, "underdouble", BOOLEAN_OBJ(true));
+    break;
+
   case HL_UNDERDOTTED:
     PUT_C(hl, "underdotted", BOOLEAN_OBJ(true));
     break;
@@ -930,8 +930,8 @@ HlAttrs dict2hlattrs(Dict(highlight) *dict, bool use_rgb, int *link_id, Error *e
   CHECK_FLAG(dict, mask, bold, , HL_BOLD);
   CHECK_FLAG(dict, mask, italic, , HL_ITALIC);
   CHECK_FLAG(dict, mask, underline, , HL_UNDERLINE);
-  CHECK_FLAG(dict, mask, underdouble, , HL_UNDERDOUBLE);
   CHECK_FLAG(dict, mask, undercurl, , HL_UNDERCURL);
+  CHECK_FLAG(dict, mask, underdouble, , HL_UNDERDOUBLE);
   CHECK_FLAG(dict, mask, underdotted, , HL_UNDERDOTTED);
   CHECK_FLAG(dict, mask, underdashed, , HL_UNDERDASHED);
   CHECK_FLAG(dict, mask, standout, , HL_STANDOUT);
diff --git a/src/nvim/highlight_defs.h b/src/nvim/highlight_defs.h
index a4dcf6eb60..95c81ac9db 100644
--- a/src/nvim/highlight_defs.h
+++ b/src/nvim/highlight_defs.h
@@ -18,8 +18,8 @@ typedef enum {
   // The next three bits are all underline styles
   HL_UNDERLINE_MASK  = 0x38,
   HL_UNDERLINE       = 0x08,
-  HL_UNDERDOUBLE     = 0x10,
-  HL_UNDERCURL       = 0x18,
+  HL_UNDERCURL       = 0x10,
+  HL_UNDERDOUBLE     = 0x18,
   HL_UNDERDOTTED     = 0x20,
   HL_UNDERDASHED     = 0x28,
   // 0x30 and 0x38 spare for underline styles
diff --git a/src/nvim/highlight_group.c b/src/nvim/highlight_group.c
index 5b1ea9967d..3d91335f55 100644
--- a/src/nvim/highlight_group.c
+++ b/src/nvim/highlight_group.c
@@ -1553,12 +1553,17 @@ static bool highlight_list_arg(const int id, bool didh, const int type, int iarg
   } else {    // type == LIST_ATTR
     buf[0] = NUL;
     for (int i = 0; hl_attr_table[i] != 0; i++) {
-      if (iarg & hl_attr_table[i]) {
+      if (((hl_attr_table[i] & HL_UNDERLINE_MASK)
+           && ((iarg & HL_UNDERLINE_MASK) == hl_attr_table[i]))
+          || (!(hl_attr_table[i] & HL_UNDERLINE_MASK)
+              && (iarg & hl_attr_table[i]))) {
         if (buf[0] != NUL) {
           xstrlcat(buf, ",", 100);
         }
         xstrlcat(buf, hl_name_table[i], 100);
-        iarg &= ~hl_attr_table[i];                // don't want "inverse"
+        if (!(hl_attr_table[i] & HL_UNDERLINE_MASK)) {
+          iarg &= ~hl_attr_table[i];  // don't want "inverse"
+        }
       }
     }
   }
diff --git a/test/functional/api/highlight_spec.lua b/test/functional/api/highlight_spec.lua
index 5941d4c68b..7f044977cb 100644
--- a/test/functional/api/highlight_spec.lua
+++ b/test/functional/api/highlight_spec.lua
@@ -214,7 +214,7 @@ describe("API: set highlight", function()
     bold = true,
     italic = true,
     reverse = true,
-    underline = true,
+    underdashed = true,
     strikethrough = true,
     altfont = true,
     cterm = {
@@ -231,7 +231,7 @@ describe("API: set highlight", function()
     bold = true,
     italic = true,
     reverse = true,
-    underline = true,
+    underdashed = true,
     strikethrough = true,
     altfont = true,
   }
@@ -297,7 +297,7 @@ describe("API: set highlight", function()
       exec_capture('highlight Test_hl'))
 
     meths.set_hl(0, 'Test_hl2', highlight3_config)
-    eq('Test_hl2       xxx cterm=italic,reverse,strikethrough,altfont,nocombine ctermfg=8 ctermbg=15 gui=bold,underline,italic,reverse,strikethrough,altfont guifg=#ff0000 guibg=#0032aa',
+    eq('Test_hl2       xxx cterm=italic,reverse,strikethrough,altfont,nocombine ctermfg=8 ctermbg=15 gui=bold,underdashed,italic,reverse,strikethrough,altfont guifg=#ff0000 guibg=#0032aa',
       exec_capture('highlight Test_hl2'))
 
     -- Colors are stored with the name they are defined, but