test(messages/cmdline_spec): convert highlight IDs to name and format (#34845)

Problem:  Hardcoded highlight IDs for ext_messages/cmdline output need
          to be adjusted everytime a builtin highlight group is added.
Solution: Store a global map of default highlights through nvim_get_hl()
          and fetch missing (custom) highlight groups through synIDattr().
          Use more compact formatting for screen:expect().

runtime/doc/ui.txt

@@ -749,8 +749,8 @@ This UI extension delegates presentation of the |cmdline| (except 'wildmenu').
 For command-line 'wildmenu' UI events, activate |ui-popupmenu|.
 
 ["cmdline_show", content, pos, firstc, prompt, indent, level, hl_id] ~
-        content: List of [attrs, string]
-	         [[{}, "t"], [attrs, "est"], ...]
+        content: List of [attrs, string, hl_id]
+	         [[{}, "t", hl_id], [attrs, "est", hl_id], ...]
 
 	Triggered when the cmdline is displayed or changed.
 	The `content` is the full content that should be displayed in the

src/nvim/ex_getln.c

@@ -3503,26 +3503,29 @@ static void ui_ext_cmdline_show(CmdlineInfo *line)
     }
     char *buf = arena_alloc(&arena, len, false);
     memset(buf, '*', len);
-    Array item = arena_array(&arena, 2);
+    Array item = arena_array(&arena, 3);
     ADD_C(item, INTEGER_OBJ(0));
     ADD_C(item, STRING_OBJ(cbuf_as_string(buf, len)));
+    ADD_C(item, INTEGER_OBJ(0));
     ADD_C(content, ARRAY_OBJ(item));
   } else if (kv_size(line->last_colors.colors)) {
     content = arena_array(&arena, kv_size(line->last_colors.colors));
     for (size_t i = 0; i < kv_size(line->last_colors.colors); i++) {
       CmdlineColorChunk chunk = kv_A(line->last_colors.colors, i);
-      Array item = arena_array(&arena, 2);
+      Array item = arena_array(&arena, 3);
       ADD_C(item, INTEGER_OBJ(chunk.hl_id == 0 ? 0 : syn_id2attr(chunk.hl_id)));
 
       assert(chunk.end >= chunk.start);
       ADD_C(item, STRING_OBJ(cbuf_as_string(line->cmdbuff + chunk.start,
                                             (size_t)(chunk.end - chunk.start))));
+      ADD_C(item, INTEGER_OBJ(chunk.hl_id));
       ADD_C(content, ARRAY_OBJ(item));
     }
   } else {
-    Array item = arena_array(&arena, 2);
+    Array item = arena_array(&arena, 3);
     ADD_C(item, INTEGER_OBJ(0));
     ADD_C(item, CSTR_AS_OBJ(line->cmdbuff));
+    ADD_C(item, INTEGER_OBJ(0));
     content = arena_array(&arena, 1);
     ADD_C(content, ARRAY_OBJ(item));
   }
@@ -3549,6 +3552,7 @@ void ui_ext_cmdline_block_append(size_t indent, const char *line)
   Array item = ARRAY_DICT_INIT;
   ADD(item, INTEGER_OBJ(0));
   ADD(item, CSTR_AS_OBJ(buf));
+  ADD(item, INTEGER_OBJ(0));
   Array content = ARRAY_DICT_INIT;
   ADD(content, ARRAY_OBJ(item));
   ADD(cmdline_block, ARRAY_OBJ(content));

test/functional/lua/ui_event_spec.lua

@@ -191,11 +191,7 @@ describe('vim.ui_attach', function()
         ^1                                       |
         {1:~                                       }|*4
       ]],
-      cmdline = { {
-        content = { { '' } },
-        firstc = ':',
-        pos = 0,
-      } },
+      cmdline = { { content = { { '' } }, firstc = ':', pos = 0 } },
     })
     feed('version<CR>')
     screen:expect({
@@ -203,7 +199,6 @@ describe('vim.ui_attach', function()
         ^2                                       |
         {1:~                                       }|*4
       ]],
-      cmdline = { { abort = false } },
       condition = function()
         eq('list_cmd', screen.messages[1].kind)
         screen.messages = {} -- Ignore the build dependent :version content
@@ -216,28 +211,12 @@ describe('vim.ui_attach', function()
         {1:~                                       }|*4
       ]],
       cmdline = {
-        {
-          content = { { '' } },
-          hl_id = 10,
-          pos = 0,
-          prompt = '[Y]es, (N)o, (C)ancel: ',
-        },
-      },
-      messages = {
-        {
-          content = { { '\nSave changes?\n', 6, 10 } },
-          kind = 'confirm',
-        },
+        { content = { { '' } }, hl = 'MoreMsg', pos = 0, prompt = '[Y]es, (N)o, (C)ancel: ' },
       },
+      messages = { { content = { { '\nSave changes?\n', 6, 'MoreMsg' } }, kind = 'confirm' } },
     })
     feed('n')
-    screen:expect({
-      grid = [[
-        ^4                                       |
-        {1:~                                       }|*4
-      ]],
-      cmdline = { { abort = false } },
-    })
+    screen:expect_unchanged()
   end)
 
   it("preserved 'incsearch/command' screen state after :redraw from ext_cmdline", function()
@@ -257,37 +236,31 @@ describe('vim.ui_attach', function()
     ]])
     -- Updates a cmdline window
     feed(':cmdline')
-    screen:expect({
-      grid = [[
-        cmdline                                 |
-        {2:cmdline [+]                             }|
-        fooba^r                                  |
-        {3:[No Name] [+]                           }|
-                                                |
-      ]],
-    })
+    screen:expect([[
+      cmdline                                 |
+      {2:cmdline [+]                             }|
+      fooba^r                                  |
+      {3:[No Name] [+]                           }|
+                                              |
+    ]])
     -- Does not clear 'incsearch' highlighting
     feed('<Esc>/foo')
-    screen:expect({
-      grid = [[
-        foo                                     |
-        {2:cmdline [+]                             }|
-        {2:foo}ba^r                                  |
-        {3:[No Name] [+]                           }|
-                                                |
-      ]],
-    })
+    screen:expect([[
+      foo                                     |
+      {2:cmdline [+]                             }|
+      {2:foo}ba^r                                  |
+      {3:[No Name] [+]                           }|
+                                              |
+    ]])
     -- Shows new cmdline state during 'inccommand'
     feed('<Esc>:%s/bar/baz')
-    screen:expect({
-      grid = [[
-        %s/bar/baz                              |
-        {2:cmdline [+]                             }|
-        foo{10:ba^z}                                  |
-        {3:[No Name] [+]                           }|
-                                                |
-      ]],
-    })
+    screen:expect([[
+      %s/bar/baz                              |
+      {2:cmdline [+]                             }|
+      foo{10:ba^z}                                  |
+      {3:[No Name] [+]                           }|
+                                              |
+    ]])
   end)
 
   it('msg_show in fast context', function()
@@ -314,10 +287,9 @@ describe('vim.ui_attach', function()
         lled in a fast event context            |
         {1:~                                       }|
       ]],
-      cmdline = { { abort = false } },
       messages = {
         {
-          content = { { 'E122: Function Foo already exists, add ! to replace it', 9, 6 } },
+          content = { { 'E122: Function Foo already exists, add ! to replace it', 9, 'ErrorMsg' } },
           history = true,
           kind = 'emsg',
         },

test/functional/ui/screen.lua

@@ -81,7 +81,8 @@ end
 --- @field cmdline table<integer,table>
 --- @field cmdline_hide_level integer?
 --- @field cmdline_block table[]
---- @field hl_groups table<string,integer>
+--- @field hl_groups table<string,integer> Highlight group to attr ID map
+--- @field hl_names table<integer,string> Highlight ID to group map
 --- @field messages table<integer,table>
 --- @field private _cursor {grid:integer,row:integer,col:integer}
 --- @field private _grids table<integer,test.functional.ui.screen.Grid>
@@ -154,6 +155,11 @@ local function _init_colors()
     [29] = { foreground = Screen.colors.SlateBlue, bold = true },
     [30] = { background = Screen.colors.Red },
   }
+
+  Screen._global_hl_names = {}
+  for group in pairs(n.api.nvim_get_hl(0, {})) do
+    Screen._global_hl_names[n.api.nvim_get_hl_id_by_name(group)] = group
+  end
 end
 
 --- @class test.functional.ui.screen.Opts
@@ -210,6 +216,7 @@ function Screen.new(width, height, options, session)
     showcmd = {},
     ruler = {},
     hl_groups = {},
+    hl_names = vim.deepcopy(Screen._global_hl_names),
     _default_attr_ids = nil,
     mouse_enabled = true,
     _attrs = {},
@@ -1343,12 +1350,12 @@ function Screen:_handle_cmdline_show(content, pos, firstc, prompt, indent, level
     firstc = firstc,
     prompt = prompt,
     indent = indent,
-    hl_id = prompt and hl_id,
+    hl = hl_id,
   }
 end
 
 function Screen:_handle_cmdline_hide(level, abort)
-  self.cmdline[level] = { abort = abort }
+  self.cmdline[level] = abort and { abort = abort } or nil
   self.cmdline_hide_level = level
 end
 
@@ -1485,6 +1492,13 @@ function Screen:_row_repr(gridnr, rownr, attr_state, cursor)
   return table.concat(rv, '') --:gsub('%s+$', '')
 end
 
+local function hl_id_to_name(self, id)
+  if id and id > 0 and not self.hl_names[id] then
+    self.hl_names[id] = n.fn.synIDattr(id, 'name')
+  end
+  return id and self.hl_names[id] or nil
+end
+
 function Screen:_extstate_repr(attr_state)
   local cmdline = {}
   for i, entry in pairs(self.cmdline) do
@@ -1492,6 +1506,7 @@ function Screen:_extstate_repr(attr_state)
     if entry.content ~= nil then
       entry.content = self:_chunks_repr(entry.content, attr_state)
     end
+    entry.hl = hl_id_to_name(self, entry.hl)
     cmdline[i] = entry
   end
 
@@ -1552,7 +1567,8 @@ function Screen:_chunks_repr(chunks, attr_state)
       attrs = hl
     end
     local attr_id = self:_get_attr_id(attr_state, attrs, hl)
-    repr_chunks[i] = { text, attr_id, attr_id and id or nil }
+    repr_chunks[i] = { text, attr_id }
+    repr_chunks[i][#repr_chunks[i] + 1] = hl_id_to_name(self, id)
   end
   return repr_chunks
 end