fix(api): don't allow hiding aucmd_win from another tabpage (#21975)

2 files changed, 40 insertions, 1 deletions

diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index 76ea4b6d7f..17cc1447ac 100644
--- a/src/nvim/api/window.c
+++ b/src/nvim/api/window.c
@@ -369,11 +369,16 @@ void nvim_win_hide(Window window, Error *err)
   tabpage_T *tabpage = win_find_tabpage(win);
   TryState tstate;
   try_enter(&tstate);
-  if (tabpage == curtab) {
+
+  // Never close the autocommand window.
+  if (is_aucmd_win(win)) {
+    emsg(_(e_autocmd_close));
+  } else if (tabpage == curtab) {
     win_close(win, false);
   } else {
     win_close_othertab(win, false, tabpage);
   }
+
   vim_ignored = try_leave(&tstate, err);
 }
 
diff --git a/test/functional/autocmd/autocmd_spec.lua b/test/functional/autocmd/autocmd_spec.lua
index 60ee9fa3a4..fb5bab445c 100644
--- a/test/functional/autocmd/autocmd_spec.lua
+++ b/test/functional/autocmd/autocmd_spec.lua
@@ -9,6 +9,7 @@ local neq = helpers.neq
 local eval = helpers.eval
 local feed = helpers.feed
 local clear = helpers.clear
+local matches = helpers.matches
 local meths = helpers.meths
 local pcall_err = helpers.pcall_err
 local funcs = helpers.funcs
@@ -435,6 +436,39 @@ describe('autocmd', function()
     end)
   end)
 
+  it('closing `aucmd_win` using API gives E813', function()
+    exec_lua([[
+      vim.cmd('tabnew')
+      _G.buf = vim.api.nvim_create_buf(true, true)
+    ]])
+    matches('Vim:E813: Cannot close autocmd window$', pcall_err(exec_lua, [[
+      vim.api.nvim_buf_call(_G.buf, function()
+        local win = vim.api.nvim_get_current_win()
+        vim.api.nvim_win_close(win, true)
+      end)
+    ]]))
+    matches('Vim:E813: Cannot close autocmd window$', pcall_err(exec_lua, [[
+      vim.api.nvim_buf_call(_G.buf, function()
+        local win = vim.api.nvim_get_current_win()
+        vim.cmd('tabnext')
+        vim.api.nvim_win_close(win, true)
+      end)
+    ]]))
+    matches('Vim:E813: Cannot close autocmd window$', pcall_err(exec_lua, [[
+      vim.api.nvim_buf_call(_G.buf, function()
+        local win = vim.api.nvim_get_current_win()
+        vim.api.nvim_win_hide(win)
+      end)
+    ]]))
+    matches('Vim:E813: Cannot close autocmd window$', pcall_err(exec_lua, [[
+      vim.api.nvim_buf_call(_G.buf, function()
+        local win = vim.api.nvim_get_current_win()
+        vim.cmd('tabnext')
+        vim.api.nvim_win_hide(win)
+      end)
+    ]]))
+  end)
+
   it(':doautocmd does not warn "No matching autocommands" #10689', function()
     local screen = Screen.new(32, 3)
     screen:attach()