fix(eval): properly support checking v:lua function in exists() (#27124)

5 files changed, 14 insertions, 13 deletions

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 775d49d2f2..9750031efd 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -1369,6 +1369,7 @@ exists({expr})                                                        *exists()*
 			echo exists("*strftime")
 			echo exists("*s:MyFunc")
 			echo exists("*MyFunc")
+			echo exists("*v:lua.Func")
 			echo exists("bufcount")
 			echo exists(":Make")
 			echo exists("#CursorHold")
diff --git a/runtime/lua/vim/_meta/vimfn.lua b/runtime/lua/vim/_meta/vimfn.lua
index 50f6e4da52..011bfb7c11 100644
--- a/runtime/lua/vim/_meta/vimfn.lua
+++ b/runtime/lua/vim/_meta/vimfn.lua
@@ -1709,6 +1709,7 @@ function vim.fn.exepath(expr) end
 ---   echo exists("*strftime")
 ---   echo exists("*s:MyFunc")
 ---   echo exists("*MyFunc")
+---   echo exists("*v:lua.Func")
 ---   echo exists("bufcount")
 ---   echo exists(":Make")
 ---   echo exists("#CursorHold")
diff --git a/src/nvim/eval.lua b/src/nvim/eval.lua
index a820f11a5e..37fded85cd 100644
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -2202,6 +2202,7 @@ M.funcs = {
       	echo exists("*strftime")
       	echo exists("*s:MyFunc")
       	echo exists("*MyFunc")
+      	echo exists("*v:lua.Func")
       	echo exists("bufcount")
       	echo exists(":Make")
       	echo exists("#CursorHold")
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 26e4e24124..d5d16fb1ef 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -1726,7 +1726,7 @@ static void f_exists(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       n = false;  // Trailing garbage.
     }
   } else if (*p == '*') {  // Internal or user defined function.
-    n = function_exists(p + 1, false);
+    n = strncmp(p, "*v:lua.", 7) == 0 ? nlua_func_exists(p + 7) : function_exists(p + 1, false);
   } else if (*p == ':') {
     n = cmd_exists(p + 1);
   } else if (*p == '#') {
@@ -1735,8 +1735,6 @@ static void f_exists(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     } else {
       n = au_exists(p + 1);
     }
-  } else if (strncmp(p, "v:lua.", 6) == 0 && nlua_func_exists(p + 6)) {
-    n = true;
   } else {  // Internal variable.
     n = var_exists(p);
   }
diff --git a/test/functional/lua/vim_spec.lua b/test/functional/lua/vim_spec.lua
index 6e05728b0c..10a2437ba2 100644
--- a/test/functional/lua/vim_spec.lua
+++ b/test/functional/lua/vim_spec.lua
@@ -4055,18 +4055,18 @@ describe('Vimscript function exists()', function()
       1,
       exec_lua [[
       _G.test = function() print("hello") end
-      return vim.fn.exists('v:lua.test')
+      return vim.fn.exists('*v:lua.test')
     ]]
     )
 
-    eq(1, fn.exists('v:lua.require("mpack").decode'))
-    eq(1, fn.exists("v:lua.require('mpack').decode"))
-    eq(1, fn.exists('v:lua.require"mpack".decode'))
-    eq(1, fn.exists("v:lua.require'mpack'.decode"))
-    eq(1, fn.exists("v:lua.require('vim.lsp').start"))
-    eq(1, fn.exists('v:lua.require"vim.lsp".start'))
-    eq(1, fn.exists("v:lua.require'vim.lsp'.start"))
-    eq(0, fn.exists("v:lua.require'vim.lsp'.unknown"))
-    eq(0, fn.exists('v:lua.?'))
+    eq(1, fn.exists('*v:lua.require("mpack").decode'))
+    eq(1, fn.exists("*v:lua.require('mpack').decode"))
+    eq(1, fn.exists('*v:lua.require"mpack".decode'))
+    eq(1, fn.exists("*v:lua.require'mpack'.decode"))
+    eq(1, fn.exists("*v:lua.require('vim.lsp').start"))
+    eq(1, fn.exists('*v:lua.require"vim.lsp".start'))
+    eq(1, fn.exists("*v:lua.require'vim.lsp'.start"))
+    eq(0, fn.exists("*v:lua.require'vim.lsp'.unknown"))
+    eq(0, fn.exists('*v:lua.?'))
   end)
 end)