fix(ui): make sure screen is valid after resizing

Problem:
When not inside an Ex command, screen_resize() calls update_screen(),
which calls screenclear() and set the screen as valid. However, when
inside an Ex command, redrawing is postponed so update_screen() screen
doesn't do anything, and the screen is still invalid after the resize,
causing ui_comp_raw_line() to be no-op until update_screen() is called
on the main loop.

Solution:
Restore the call to screenclear() inside screen_resize() so that the
screen is invalid after screen_resize(). Since screenclear() changes
redraw type from UPD_CLEAR to UPD_NOT_VALID, it is called at most once
for each resize, so this shouldn't change how much code is run in the
common (not inside an Ex command) case.

2 files changed, 80 insertions, 5 deletions

diff --git a/src/nvim/drawscreen.c b/src/nvim/drawscreen.c
index 2bc335a7e0..814d443031 100644
--- a/src/nvim/drawscreen.c
+++ b/src/nvim/drawscreen.c
@@ -318,6 +318,10 @@ void screen_resize(int width, int height)
   resizing_autocmd = false;
   redraw_all_later(UPD_CLEAR);
 
+  if (State != MODE_ASKMORE && State != MODE_EXTERNCMD && State != MODE_CONFIRM) {
+    screenclear();
+  }
+
   if (starting != NO_SCREEN) {
     maketitle();
 
diff --git a/test/functional/ui/screen_basic_spec.lua b/test/functional/ui/screen_basic_spec.lua
index 3bd2289a73..439021ad87 100644
--- a/test/functional/ui/screen_basic_spec.lua
+++ b/test/functional/ui/screen_basic_spec.lua
@@ -61,6 +61,7 @@ local function screen_tests(linegrid)
       [5] = {background = Screen.colors.LightGrey, underline = true, bold = true, foreground = Screen.colors.Fuchsia},
       [6] = {bold = true, foreground = Screen.colors.Fuchsia},
       [7] = {bold = true, foreground = Screen.colors.SeaGreen},
+      [8] = {foreground = Screen.colors.White, background = Screen.colors.Red},
     } )
   end)
 
@@ -866,12 +867,9 @@ local function screen_tests(linegrid)
   end)
 
   describe('resize', function()
-    before_each(function()
+    it('rebuilds the whole screen', function()
       screen:try_resize(25, 5)
       feed('iresize')
-    end)
-
-    it('rebuilds the whole screen', function()
       screen:expect([[
         resize^                   |
         {0:~                        }|
@@ -882,6 +880,7 @@ local function screen_tests(linegrid)
     end)
 
     it('has minimum width/height values', function()
+      feed('iresize')
       screen:try_resize(1, 1)
       screen:expect([[
         resize^      |
@@ -896,7 +895,8 @@ local function screen_tests(linegrid)
     end)
 
     it('VimResized autocommand does not cause invalid UI events #20692 #20759', function()
-      feed('<Esc>')
+      screen:try_resize(25, 5)
+      feed('iresize<Esc>')
       command([[autocmd VimResized * redrawtabline]])
       command([[autocmd VimResized * lua vim.api.nvim_echo({ { 'Hello' } }, false, {})]])
       command([[autocmd VimResized * let g:echospace = v:echospace]])
@@ -919,6 +919,77 @@ local function screen_tests(linegrid)
       ]])
       eq(29, meths.get_var('echospace'))
     end)
+
+    it('messages from the same Ex command as resize are visible #22225', function()
+      feed(':set columns=20 | call<CR>')
+      screen:expect([[
+                            |
+                            |
+                            |
+                            |
+                            |
+                            |
+                            |
+                            |
+                            |
+        {1:                    }|
+        {8:E471: Argument requi}|
+        {8:red}                 |
+        {7:Press ENTER or type }|
+        {7:command to continue}^ |
+      ]])
+      feed('<CR>')
+      screen:expect([[
+        ^                    |
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+        {0:~                   }|
+                            |
+      ]])
+      feed(':set columns=0<CR>')
+      screen:expect([[
+                    |
+                    |
+                    |
+                    |
+                    |
+        {1:            }|
+        {8:E594: Need a}|
+        {8:t least 12 c}|
+        {8:olumns: colu}|
+        {8:mns=0}       |
+        {7:Press ENTER }|
+        {7:or type comm}|
+        {7:and to conti}|
+        {7:nue}^         |
+      ]])
+      feed('<CR>')
+      screen:expect([[
+        ^            |
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+        {0:~           }|
+                    |
+      ]])
+    end)
   end)
 
   describe('press enter', function()