fix(inccommand): improve preview buffer number handling (#27087)

1 files changed, 18 insertions, 0 deletions

diff --git a/test/functional/ui/inccommand_user_spec.lua b/test/functional/ui/inccommand_user_spec.lua
index d30575a9f9..a714df72b7 100644
--- a/test/functional/ui/inccommand_user_spec.lua
+++ b/test/functional/ui/inccommand_user_spec.lua
@@ -1,6 +1,8 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
+local api = helpers.api
 local clear = helpers.clear
+local eq = helpers.eq
 local exec_lua = helpers.exec_lua
 local insert = helpers.insert
 local feed = helpers.feed
@@ -495,6 +497,22 @@ describe("'inccommand' for user commands", function()
       test_preview_break_undo()
     end)
   end)
+
+  it('disables preview if preview buffer cannot be created #27086', function()
+    command('set inccommand=split')
+    api.nvim_buf_set_name(0, '[Preview]')
+    exec_lua([[
+      vim.api.nvim_create_user_command('Test', function() end, {
+        nargs = '*',
+        preview = function(_, _, _)
+          return 2
+        end
+      })
+    ]])
+    eq('split', api.nvim_get_option_value('inccommand', {}))
+    feed(':Test')
+    eq('nosplit', api.nvim_get_option_value('inccommand', {}))
+  end)
 end)
 
 describe("'inccommand' with multiple buffers", function()