feat(eval)!: make Vim functions return inner window width and height (#19743)

In non-multigrid UI the only change is that the returned height now
excludes winbar, and this is compatible with Vim.

In multigrid UI this means the return value of these functions now
reflect the space available for buffer lines in a window.

No change in nvim_win_get_height() and nvim_win_get_width().

1 files changed, 11 insertions, 0 deletions

diff --git a/test/functional/ui/multigrid_spec.lua b/test/functional/ui/multigrid_spec.lua
index b30aa67fd3..78a1e8c677 100644
--- a/test/functional/ui/multigrid_spec.lua
+++ b/test/functional/ui/multigrid_spec.lua
@@ -3,7 +3,9 @@ local Screen = require('test.functional.ui.screen')
 local clear = helpers.clear
 local feed, command, insert = helpers.feed, helpers.command, helpers.insert
 local eq = helpers.eq
+local funcs = helpers.funcs
 local meths = helpers.meths
+local curwin = helpers.curwin
 local poke_eventloop = helpers.poke_eventloop
 
 
@@ -871,6 +873,15 @@ describe('ext_multigrid', function()
     before_each(function()
       screen:try_resize_grid(2, 60, 20)
     end)
+
+    it('winwidth() winheight() getwininfo() return inner width and height #19743', function()
+      eq(60, funcs.winwidth(0))
+      eq(20, funcs.winheight(0))
+      local win_info = funcs.getwininfo(curwin().id)[1]
+      eq(60, win_info.width)
+      eq(20, win_info.height)
+    end)
+
     it('gets written till grid width', function()
       insert(('a'):rep(60).."\n")