Merge pull request #9985 from bfredl/shenanigans

Fix aucmd_win issues: crashes and redrawing errors.

src/nvim/fileio.c

@@ -11,6 +11,7 @@
 #include <fcntl.h>
 
 #include "nvim/vim.h"
+#include "nvim/api/private/handle.h"
 #include "nvim/ascii.h"
 #include "nvim/fileio.h"
 #include "nvim/buffer.h"
@@ -47,6 +48,7 @@
 #include "nvim/state.h"
 #include "nvim/strings.h"
 #include "nvim/ui.h"
+#include "nvim/ui_compositor.h"
 #include "nvim/types.h"
 #include "nvim/undo.h"
 #include "nvim/window.h"
@@ -6586,6 +6588,8 @@ void aucmd_prepbuf(aco_save_T *aco, buf_T *buf)
     block_autocmds();  // We don't want BufEnter/WinEnter autocommands.
     if (need_append) {
       win_append(lastwin, aucmd_win);
+      handle_register_window(aucmd_win);
+      win_config_float(aucmd_win, aucmd_win->w_float_config);
     }
     // Prevent chdir() call in win_enter_ext(), through do_autochdir()
     int save_acd = p_acd;
@@ -6625,6 +6629,13 @@ void aucmd_restbuf(aco_save_T *aco)
 win_found:
 
     win_remove(curwin, NULL);
+    handle_unregister_window(curwin);
+    if (curwin->w_grid.chars != NULL) {
+      ui_comp_remove_grid(&curwin->w_grid);
+      ui_call_win_hide(curwin->w_grid.handle);
+      grid_free(&curwin->w_grid);
+    }
+
     aucmd_win_used = false;
     last_status(false);         // may need to remove last status line
 

src/nvim/window.c

@@ -3418,8 +3418,8 @@ void win_alloc_aucmd_win(void)
 {
   Error err = ERROR_INIT;
   FloatConfig fconfig = FLOAT_CONFIG_INIT;
-  fconfig.width = 20;
+  fconfig.width = Columns;
-  fconfig.height = 20;
+  fconfig.height = 5;
   fconfig.focusable = false;
   aucmd_win = win_new_float(NULL, fconfig, &err);
   aucmd_win->w_buffer->b_nwindows--;

test/functional/autocmd/autocmd_spec.lua

@@ -1,4 +1,5 @@
 local helpers = require('test.functional.helpers')(after_each)
+local Screen = require('test.functional.ui.screen')
 
 local dedent = helpers.dedent
 local eq = helpers.eq
@@ -6,11 +7,13 @@ local eval = helpers.eval
 local feed = helpers.feed
 local clear = helpers.clear
 local meths = helpers.meths
+local meth_pcall = helpers.meth_pcall
 local funcs = helpers.funcs
 local expect = helpers.expect
 local command = helpers.command
 local exc_exec = helpers.exc_exec
 local curbufmeths = helpers.curbufmeths
+local source = helpers.source
 
 describe('autocmd', function()
   before_each(clear)
@@ -144,4 +147,117 @@ describe('autocmd', function()
        --- Autocommands ---]]),
        funcs.execute('autocmd Tabnew'))
   end)
+
+  it('window works', function()
+    -- Nvim uses a special window to execute certain actions for an invisible buffer,
+    -- internally called autcmd_win and mentioned in the docs at :help E813
+    -- Do some safety checks for redrawing and api accesses to this window.
+
+    local screen = Screen.new(50, 10)
+    screen:attach()
+    screen:set_default_attr_ids({
+      [1] = {bold = true, foreground = Screen.colors.Blue1},
+      [2] = {background = Screen.colors.LightMagenta},
+      [3] = {background = Screen.colors.LightMagenta, bold = true, foreground = Screen.colors.Blue1},
+    })
+
+    source([[
+      function! Doit()
+        let g:winid = nvim_get_current_win()
+        redraw!
+        echo getchar()
+        " API functions work when aucmd_win is in scope
+        let g:had_value = has_key(w:, "testvar")
+        call nvim_win_set_var(g:winid, "testvar", 7)
+        let g:test = w:testvar
+      endfunction
+      set hidden
+      " add dummy text to not discard the buffer
+      call setline(1,"bb")
+      autocmd User <buffer> call Doit()
+    ]])
+    screen:expect([[
+      ^bb                                                |
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+                                                        |
+    ]])
+
+    feed(":enew | doautoall User<cr>")
+    screen:expect([[
+      {2:bb                                                }|
+      {3:~                                                 }|
+      {3:~                                                 }|
+      {3:~                                                 }|
+      {3:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      ^:enew | doautoall User                            |
+    ]])
+
+    feed('<cr>')
+    screen:expect([[
+      ^                                                  |
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      13                                                |
+    ]])
+    eq(7, eval('g:test'))
+
+    -- API calls are blocked when aucmd_win is not in scope
+    eq({false, 'Vim(call):Invalid window id'},
+       meth_pcall(command, "call nvim_set_current_win(g:winid)"))
+
+    -- second time aucmd_win is needed, a different code path is invoked
+    -- to reuse the same window, so check again
+    command("let g:test = v:null")
+    command("let g:had_value = v:null")
+    feed(":doautoall User<cr>")
+    screen:expect([[
+      {2:bb                                                }|
+      {3:~                                                 }|
+      {3:~                                                 }|
+      {3:~                                                 }|
+      {3:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      ^:doautoall User                                   |
+    ]])
+
+    feed('<cr>')
+    screen:expect([[
+      ^                                                  |
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      13                                                |
+    ]])
+    -- win vars in aucmd_win should have been reset
+    eq(0, eval('g:had_value'))
+    eq(7, eval('g:test'))
+
+    eq({false, 'Vim(call):Invalid window id'},
+       meth_pcall(command, "call nvim_set_current_win(g:winid)"))
+  end)
 end)