fix(api, lua): return NIL on failure to find converted function (#17779)

src/nvim/api/private/converter.c

@@ -65,8 +65,7 @@ typedef struct {
 #define TYPVAL_ENCODE_CONV_FUNC_START(tv, fun) \
   do { \
     ufunc_T *fp = find_func(fun); \
-    assert(fp != NULL); \
+    if (fp != NULL && fp->uf_cb == nlua_CFunction_func_call) { \
-    if (fp->uf_cb == nlua_CFunction_func_call) { \
       LuaRef ref = api_new_luaref(((LuaCFunctionState *)fp->uf_cb_state)->lua_callable.func_ref); \
       kvi_push(edata->stack, LUAREF_OBJ(ref)); \
     } else { \

src/nvim/lua/converter.c

@@ -477,8 +477,7 @@ static bool typval_conv_special = false;
 #define TYPVAL_ENCODE_CONV_FUNC_START(tv, fun) \
   do { \
     ufunc_T *fp = find_func(fun); \
-    assert(fp != NULL); \
+    if (fp != NULL && fp->uf_cb == nlua_CFunction_func_call) { \
-    if (fp->uf_cb == nlua_CFunction_func_call) { \
       nlua_pushref(lstate, ((LuaCFunctionState *)fp->uf_cb_state)->lua_callable.func_ref); \
     } else { \
       TYPVAL_ENCODE_CONV_NIL(tv); \

test/functional/api/vim_spec.lua

@@ -6,6 +6,7 @@ local assert_alive = helpers.assert_alive
 local NIL = helpers.NIL
 local clear, nvim, eq, neq = helpers.clear, helpers.nvim, helpers.eq, helpers.neq
 local command = helpers.command
+local exec = helpers.exec
 local eval = helpers.eval
 local expect = helpers.expect
 local funcs = helpers.funcs
@@ -1271,6 +1272,17 @@ describe('API', function()
       eq('Key is locked: lua', pcall_err(meths.del_var, 'lua'))
       eq('Key is locked: lua', pcall_err(meths.set_var, 'lua', 1))
 
+      exec([[
+        function Test()
+        endfunction
+        function s:Test()
+        endfunction
+        let g:Unknown_func = function('Test')
+        let g:Unknown_script_func = function('s:Test')
+      ]])
+      eq(NIL, meths.get_var('Unknown_func'))
+      eq(NIL, meths.get_var('Unknown_script_func'))
+
       -- Check if autoload works properly
       local pathsep = helpers.get_pathsep()
       local xconfig = 'Xhome' .. pathsep .. 'Xconfig'

test/functional/lua/vim_spec.lua

@@ -1043,6 +1043,17 @@ describe('lua stdlib', function()
     exec_lua([[vim.api.nvim_get_var('funcs').add()]])
     eq(6, exec_lua([[return vim.api.nvim_get_var('funcs').get()]]))
 
+    exec([[
+      function Test()
+      endfunction
+      function s:Test()
+      endfunction
+      let g:Unknown_func = function('Test')
+      let g:Unknown_script_func = function('s:Test')
+    ]])
+    eq(NIL, exec_lua([[return vim.g.Unknown_func]]))
+    eq(NIL, exec_lua([[return vim.g.Unknown_script_func]]))
+
     -- Check if autoload works properly
     local pathsep = helpers.get_pathsep()
     local xconfig = 'Xhome' .. pathsep .. 'Xconfig'
@@ -1136,6 +1147,17 @@ describe('lua stdlib', function()
     exec_lua([[vim.api.nvim_buf_get_var(0, 'funcs').add()]])
     eq(6, exec_lua([[return vim.api.nvim_buf_get_var(0, 'funcs').get()]]))
 
+    exec([[
+      function Test()
+      endfunction
+      function s:Test()
+      endfunction
+      let b:Unknown_func = function('Test')
+      let b:Unknown_script_func = function('s:Test')
+    ]])
+    eq(NIL, exec_lua([[return vim.b.Unknown_func]]))
+    eq(NIL, exec_lua([[return vim.b.Unknown_script_func]]))
+
     exec_lua [[
     vim.cmd "vnew"
     ]]
@@ -1219,6 +1241,17 @@ describe('lua stdlib', function()
     exec_lua([[vim.api.nvim_win_get_var(0, 'funcs').add()]])
     eq(6, exec_lua([[return vim.api.nvim_win_get_var(0, 'funcs').get()]]))
 
+    exec([[
+      function Test()
+      endfunction
+      function s:Test()
+      endfunction
+      let w:Unknown_func = function('Test')
+      let w:Unknown_script_func = function('s:Test')
+    ]])
+    eq(NIL, exec_lua([[return vim.w.Unknown_func]]))
+    eq(NIL, exec_lua([[return vim.w.Unknown_script_func]]))
+
     exec_lua [[
     vim.cmd "vnew"
     ]]