vim-patch:9.0.0115: when 'cmdheight' is zero pressing ':' may scroll a window

Problem:    When 'cmdheight' is zero pressing ':' may scroll a window.
Solution:   Add the made_cmdheight_nonzero flag and set 'scrolloff' to zero.
https://github.com/vim/vim/commit/6747cf1671bd41cddee77c65b3f9a70509f968db

1 files changed, 15 insertions, 1 deletions

diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index be7e7377ed..a6e8ad433f 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -692,9 +692,19 @@ static uint8_t *command_line_enter(int firstc, long count, int indent, bool init
   const bool cmdheight0 = !ui_has_messages();
 
   if (cmdheight0) {
-    // If cmdheight is 0, cmdheight must be set to 1 when we enter command line.
+    const long save_so = lastwin->w_p_so;
+
+    // If cmdheight is 0, cmdheight must be set to 1 when we enter the
+    // command line.  Set "made_cmdheight_nonzero" and reset 'scrolloff' to
+    // avoid scrolling the last window.
+    made_cmdheight_nonzero = true;
+
+    lastwin->w_p_so = 0;
     set_option_value("ch", 1L, NULL, 0);
     update_screen(VALID);                 // redraw the screen NOW
+
+    made_cmdheight_nonzero = false;
+    lastwin->w_p_so = save_so;
   }
 
   // can be invoked recursively, identify each level
@@ -991,10 +1001,14 @@ theend:
   }
 
   if (cmdheight0) {
+    made_cmdheight_nonzero = true;
+
     // Restore cmdheight
     set_option_value("ch", 0L, NULL, 0);
     // Redraw is needed for command line completion
     redraw_all_later(CLEAR);
+
+    made_cmdheight_nonzero = false;
   }
 
   return p;