screen: setup scrolling main screen when starting with display-=msgsep

src/nvim/ui.c

@@ -110,6 +110,7 @@ static char uilog_last_event[1024] = { 0 };
 void ui_init(void)
 {
   default_grid.handle = 1;
+  msg_grid_adj.target = &default_grid;
   ui_comp_init();
 }
 

test/functional/ui/screen_basic_spec.lua

@@ -24,10 +24,6 @@ describe('screen', function()
     } )
   end)
 
-  after_each(function()
-    screen:detach()
-  end)
-
   it('default initial screen', function()
       screen:expect([[
       ^                                                     |
@@ -67,10 +63,6 @@ local function screen_tests(linegrid)
     } )
   end)
 
-  after_each(function()
-    screen:detach()
-  end)
-
   describe(':suspend', function()
     it('is forwarded to the UI', function()
       local function check()
@@ -1004,3 +996,39 @@ describe('Screen default colors', function()
     end}
   end)
 end)
+
+
+describe('screen with msgsep deactivated on startup', function()
+  local screen
+
+  before_each(function()
+    clear('--cmd', 'set display-=msgsep')
+    screen = Screen.new()
+    screen:attach()
+    screen:set_default_attr_ids {
+      [0] = {bold=true, foreground=255};
+      [7] = {bold = true, foreground = Screen.colors.SeaGreen};
+    }
+  end)
+
+  it('execute command with multi-line output', function()
+    feed ':ls<cr>'
+    screen:expect([[
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      {0:~                                                    }|
+      :ls                                                  |
+        1 %a   "[No Name]"                    line 1       |
+      {7:Press ENTER or type command to continue}^              |
+    ]])
+    feed '<cr>'  -- skip the "Press ENTER..." state or tests will hang
+  end)
+end)