vim-patch:8.1.2227: layout wrong if 'lines' changes while cmdline window is open

Problem:    Layout wrong if 'lines' changes while cmdline window is open.
Solution:   Do not restore the window layout if 'lines' changed.
            (closes vim/vim#5130)
https://github.com/vim/vim/commit/1c329c04be2e95a3589a53f2978926e91b450cca

2 files changed, 44 insertions, 11 deletions

diff --git a/src/nvim/testdir/test_cmdline.vim b/src/nvim/testdir/test_cmdline.vim
index 0c31619086..5b23525ab5 100644
--- a/src/nvim/testdir/test_cmdline.vim
+++ b/src/nvim/testdir/test_cmdline.vim
@@ -850,6 +850,36 @@ func Test_cmdwin_cedit()
   delfunc CmdWinType
 endfunc
 
+func Test_cmdwin_restore()
+  CheckScreendump
+
+  let lines =<< trim [SCRIPT]
+    call setline(1, range(30))
+    2split
+  [SCRIPT]
+  call writefile(lines, 'XTest_restore')
+
+  let buf = RunVimInTerminal('-S XTest_restore', {'rows': 12})
+  call term_wait(buf, 100)
+  call term_sendkeys(buf, "q:")
+  call VerifyScreenDump(buf, 'Test_cmdwin_restore_1', {})
+
+  " normal restore
+  call term_sendkeys(buf, ":q\<CR>")
+  call VerifyScreenDump(buf, 'Test_cmdwin_restore_2', {})
+
+  " restore after setting 'lines' with one window
+  call term_sendkeys(buf, ":close\<CR>")
+  call term_sendkeys(buf, "q:")
+  call term_sendkeys(buf, ":set lines=18\<CR>")
+  call term_sendkeys(buf, ":q\<CR>")
+  call VerifyScreenDump(buf, 'Test_cmdwin_restore_3', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('XTest_restore')
+endfunc
+
 func Test_buffers_lastused()
   " check that buffers are sorted by time when wildmode has lastused
   edit bufc " oldest
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 6ecfd9ab64..2dcce2d8cb 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -5013,7 +5013,10 @@ void win_size_save(garray_T *gap)
 
 {
   ga_init(gap, (int)sizeof(int), 1);
-  ga_grow(gap, win_count() * 2);
+  ga_grow(gap, win_count() * 2 + 1);
+  // first entry is value of 'lines'
+  ((int *)gap->ga_data)[gap->ga_len++] = Rows;
+
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
     ((int *)gap->ga_data)[gap->ga_len++] =
       wp->w_width + wp->w_vsep_width;
@@ -5021,18 +5024,18 @@ void win_size_save(garray_T *gap)
   }
 }
 
-/*
- * Restore window sizes, but only if the number of windows is still the same.
- * Does not free the growarray.
- */
+// Restore window sizes, but only if the number of windows is still the same
+// and 'lines' didn't change.
+// Does not free the growarray.
 void win_size_restore(garray_T *gap)
+  FUNC_ATTR_NONNULL_ALL
 {
-  if (win_count() * 2 == gap->ga_len) {
-    /* The order matters, because frames contain other frames, but it's
-     * difficult to get right. The easy way out is to do it twice. */
-    for (int j = 0; j < 2; ++j)
-    {
-      int i = 0;
+  if (win_count() * 2 + 1 == gap->ga_len
+      && ((int *)gap->ga_data)[0] == Rows) {
+    // The order matters, because frames contain other frames, but it's
+    // difficult to get right. The easy way out is to do it twice.
+    for (int j = 0; j < 2; j++) {
+      int i = 1;
       FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
         int width = ((int *)gap->ga_data)[i++];
         int height = ((int *)gap->ga_data)[i++];