api: {get,set}_option should {get,set} global value of local options (#6405)

- nvim_get_option should return the global default of a local option.
- nvim_set_option should set the global default of a local option.

1 files changed, 22 insertions, 0 deletions

diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 3348368a36..8f9f155110 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -153,6 +153,28 @@ describe('api', function()
       nvim('set_option', 'equalalways', false)
       ok(not nvim('get_option', 'equalalways'))
     end)
+
+    it('works to get global value of local options', function()
+      eq(false, nvim('get_option', 'lisp'))
+      eq(8, nvim('get_option', 'shiftwidth'))
+    end)
+
+    it('works to set global value of local options', function()
+      nvim('set_option', 'lisp', true)
+      eq(true, nvim('get_option', 'lisp'))
+      eq(false, helpers.curbuf('get_option', 'lisp'))
+      eq(nil, nvim('command_output', 'setglobal lisp?'):match('nolisp'))
+      eq('nolisp', nvim('command_output', 'setlocal lisp?'):match('nolisp'))
+      nvim('set_option', 'shiftwidth', 20)
+      eq('20', nvim('command_output', 'setglobal shiftwidth?'):match('%d+'))
+      eq('8', nvim('command_output', 'setlocal shiftwidth?'):match('%d+'))
+    end)
+
+    it('most window-local options have no global value', function()
+      local status, err = pcall(nvim, 'get_option', 'foldcolumn')
+      eq(false, status)
+      ok(err:match('Invalid option name') ~= nil)
+    end)
   end)
 
   describe('nvim_{get,set}_current_buf, nvim_list_bufs', function()