screen: fix problem with p_ch

When the screen is resized, p_ch is not re-set to the appropriate value.
As a result, access to invalid addresses was occurring.

2 files changed, 16 insertions, 0 deletions

diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 1e20b77c5c..384636f705 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -7507,6 +7507,10 @@ void screen_resize(int width, int height)
   Rows = height;
   Columns = width;
   check_shellsize();
+  int max_p_ch = Rows - min_rows() + 1;
+  if (!ui_has(kUIMessages) && p_ch > max_p_ch) {
+    p_ch = max_p_ch ? max_p_ch : 1;
+  }
   height = Rows;
   width = Columns;
   p_lines = Rows;
diff --git a/test/functional/ui/cmdline_spec.lua b/test/functional/ui/cmdline_spec.lua
index 21c01b3458..29a76c7a07 100644
--- a/test/functional/ui/cmdline_spec.lua
+++ b/test/functional/ui/cmdline_spec.lua
@@ -3,6 +3,7 @@ local Screen = require('test.functional.ui.screen')
 local clear, feed = helpers.clear, helpers.feed
 local source = helpers.source
 local command = helpers.command
+local assert_alive = helpers.assert_alive
 
 local function new_screen(opt)
   local screen = Screen.new(25, 5)
@@ -842,3 +843,14 @@ describe('cmdline redraw', function()
     ]], unchanged=true}
   end)
 end)
+
+describe("cmdline height", function()
+  it("does not crash resized screen #14263", function()
+    clear()
+    local screen = Screen.new(25, 10)
+    screen:attach()
+    command('set cmdheight=9999')
+    screen:try_resize(25, 5)
+    assert_alive()
+  end)
+end)