fix(lsp): ensure bufstate when calling vim.lsp.document_color.is_enabled

runtime/lua/vim/lsp/document_color.lua

@@ -238,7 +238,13 @@ end
 function M.is_enabled(bufnr)
   vim.validate('bufnr', bufnr, 'number', true)
 
-  return bufstates[vim._resolve_bufnr(bufnr)].enabled
+  bufnr = vim._resolve_bufnr(bufnr)
+
+  if not bufstates[bufnr] then
+    reset_bufstate(bufnr, false)
+  end
+
+  return bufstates[bufnr].enabled
 end
 
 --- Enables document highlighting from the given language client in the given buffer.

test/functional/plugin/lsp/document_color_spec.lua

@@ -159,6 +159,15 @@ body {
         end)
       )
     end)
+
+    it('does not error when called on a new unattached buffer', function()
+      eq(
+        false,
+        exec_lua(function()
+          return vim.lsp.document_color.is_enabled(vim.api.nvim_create_buf(false, true))
+        end)
+      )
+    end)
   end)
 
   describe('enable()', function()