vim-patch:8.2.2655: The -w command line argument doesn't work

Problem:    The -w command line argument doesn't work.
Solution:   Don't set 'window' when set with the -w argument. (closes vim/vim#8011)
https://github.com/vim/vim/commit/0a1a6a1aa4004d0e4d64cc375540156b8bd92a87

Cherry-pick Test_w_arg() from patch v8.2.0509.

2 files changed, 33 insertions, 2 deletions

diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 1e20b77c5c..760a54a316 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -7609,8 +7609,9 @@ void win_new_shellsize(void)
   static long old_Columns = 0;
 
   if (old_Rows != Rows) {
-    // if 'window' uses the whole screen, keep it using that */
-    if (p_window == old_Rows - 1 || old_Rows == 0) {
+    // If 'window' uses the whole screen, keep it using that.
+    // Don't change it when set with "-w size" on the command line.
+    if (p_window == old_Rows - 1 || (old_Rows == 0 && p_window == 0)) {
       p_window = Rows - 1;
     }
     old_Rows = Rows;
diff --git a/src/nvim/testdir/test_startup.vim b/src/nvim/testdir/test_startup.vim
index eb9378194f..63affd6910 100644
--- a/src/nvim/testdir/test_startup.vim
+++ b/src/nvim/testdir/test_startup.vim
@@ -890,6 +890,36 @@ func Test_not_a_term()
 endfunc
 
 
+" Test for the "-w scriptout" argument
+func Test_w_arg()
+  " Can't catch the output of gvim.
+  CheckNotGui
+
+  call writefile(["iVim Editor\<Esc>:q!\<CR>"], 'Xscriptin', 'b')
+  if RunVim([], [], '-s Xscriptin -w Xscriptout')
+    call assert_equal(["iVim Editor\e:q!\r"], readfile('Xscriptout'))
+    call delete('Xscriptout')
+  endif
+  call delete('Xscriptin')
+
+  " Test for failing to open the script output file. This test works only when
+  " the language is English.
+  if v:lang == "C" || v:lang =~ '^[Ee]n'
+    call mkdir("Xdir")
+    let m = system(GetVimCommand() .. " -w Xdir")
+    call assert_equal("Cannot open for script output: \"Xdir\"\n", m)
+    call delete("Xdir", 'rf')
+  endif
+
+  " A number argument sets the 'window' option
+  call writefile(["iwindow \<C-R>=&window\<CR>\<Esc>:wq! Xresult\<CR>"], 'Xscriptin', 'b')
+  if RunVim([], [], '-s Xscriptin -w 17')
+    call assert_equal(["window 17"], readfile('Xresult'))
+    call delete('Xresult')
+  endif
+  call delete('Xscriptin')
+endfunc
+
 " Test starting vim with various names: vim, ex, view, evim, etc.
 func Test_progname()
   CheckUnix