vim-patch:9.1.0547: No way to get the arity of a Vim function (#29638)

Problem:  No way to get the arity of a Vim function
          (Austin Ziegler)
Solution: Enhance get() Vim script function to return the function
          argument info using get(func, "arity") (LemonBoy)

fixes: vim/vim#15097
closes: vim/vim#15109

https://github.com/vim/vim/commit/48b7d05a4f88c4326bd5d7a73a523f2d953b3e51

Co-authored-by: LemonBoy <thatlemon@gmail.com>

2 files changed, 32 insertions, 0 deletions

diff --git a/test/old/testdir/test_getvar.vim b/test/old/testdir/test_getvar.vim
index 1e29f49fb4..56f737ab9c 100644
--- a/test/old/testdir/test_getvar.vim
+++ b/test/old/testdir/test_getvar.vim
@@ -142,21 +142,31 @@ func Test_get_func()
   let l:F = function('tr')
   call assert_equal('tr', get(l:F, 'name'))
   call assert_equal(l:F, get(l:F, 'func'))
+  call assert_equal({'required': 3, 'optional': 0, 'varargs': v:false},
+      \ get(l:F, 'arity'))
 
   let Fb_func = function('s:FooBar')
   call assert_match('<SNR>\d\+_FooBar', get(Fb_func, 'name'))
+  call assert_equal({'required': 0, 'optional': 0, 'varargs': v:false},
+      \ get(Fb_func, 'arity'))
   let Fb_ref = funcref('s:FooBar')
   call assert_match('<SNR>\d\+_FooBar', get(Fb_ref, 'name'))
+  call assert_equal({'required': 0, 'optional': 0, 'varargs': v:false},
+      \ get(Fb_ref, 'arity'))
 
   call assert_equal({'func has': 'no dict'}, get(l:F, 'dict', {'func has': 'no dict'}))
   call assert_equal(0, get(l:F, 'dict'))
   call assert_equal([], get(l:F, 'args'))
+
   " Nvim doesn't have null functions
   " let NF = test_null_function()
   " call assert_equal('', get(NF, 'name'))
   " call assert_equal(NF, get(NF, 'func'))
   " call assert_equal(0, get(NF, 'dict'))
   " call assert_equal([], get(NF, 'args'))
+  " call assert_equal({'required': 0, 'optional': 0, 'varargs': v:false}, get(NF, 'arity'))
 endfunc
 
 " get({partial}, {what} [, {default}]) - in test_partial.vim
+
+" vim: shiftwidth=2 sts=2 expandtab
diff --git a/test/old/testdir/test_partial.vim b/test/old/testdir/test_partial.vim
index 8b62e4a0e5..d049cc9e4b 100644
--- a/test/old/testdir/test_partial.vim
+++ b/test/old/testdir/test_partial.vim
@@ -284,6 +284,11 @@ func Test_auto_partial_rebind()
 endfunc
 
 func Test_get_partial_items()
+  func s:Qux(x, y, z=3, w=1, ...)
+  endfunc
+  func s:Qux1(x, y)
+  endfunc
+
   let dict = {'name': 'hello'}
   let args = ["foo", "bar"]
   let Func = function('MyDictFunc')
@@ -304,6 +309,23 @@ func Test_get_partial_items()
   let dict = {'partial has': 'no dict'}
   call assert_equal(dict, get(P, 'dict', dict))
   call assert_equal(0, get(l:P, 'dict'))
+
+  call assert_equal({'required': 2, 'optional': 2, 'varargs': v:true},
+      \ get(funcref('s:Qux', []), 'arity'))
+  call assert_equal({'required': 1, 'optional': 2, 'varargs': v:true},
+      \ get(funcref('s:Qux', [1]), 'arity'))
+  call assert_equal({'required': 0, 'optional': 2, 'varargs': v:true},
+      \ get(funcref('s:Qux', [1, 2]), 'arity'))
+  call assert_equal({'required': 0, 'optional': 1, 'varargs': v:true},
+      \ get(funcref('s:Qux', [1, 2, 3]), 'arity'))
+  call assert_equal({'required': 0, 'optional': 0, 'varargs': v:true},
+      \ get(funcref('s:Qux', [1, 2, 3, 4]), 'arity'))
+  " More args than expected is not an error
+  call assert_equal({'required': 0, 'optional': 0, 'varargs': v:false},
+      \ get(funcref('s:Qux1', [1, 2, 3, 4]), 'arity'))
+
+  delfunc s:Qux
+  delfunc s:Qux1
 endfunc
 
 func Test_compare_partials()