fix(lua): memory leak when using invalid syntax with exists() (#26530)

src/nvim/lua/executor.c

@@ -2323,10 +2323,12 @@ bool nlua_func_exists(const char *lua_funcname)
   vim_snprintf(str, length, "return %s", lua_funcname);
   ADD_C(args, CSTR_AS_OBJ(str));
   Error err = ERROR_INIT;
-  Object result = NLUA_EXEC_STATIC("return type(loadstring(...)()) =='function'", args, &err);
+  Object result = NLUA_EXEC_STATIC("return type(loadstring(...)()) == 'function'", args, &err);
   xfree(str);
 
+  api_clear_error(&err);
   if (result.type != kObjectTypeBoolean) {
+    api_free_object(result);
     return false;
   }
   return result.data.boolean;

test/functional/lua/vim_spec.lua

@@ -3351,32 +3351,23 @@ describe('vim.keymap', function()
 
     eq(1, exec_lua[[return GlobalCount]])
   end)
-
-  it('exists() can check a lua function', function()
-    eq(true, exec_lua[[
-      _G.test = function() print("hello") end
-      return vim.fn.exists('v:lua.test') == 1
-    ]])
-
-    eq(true, exec_lua[[
-      return vim.fn.exists('v:lua.require("mpack").decode') == 1
-    ]])
-
-    eq(true, exec_lua[[
-      return vim.fn.exists("v:lua.require('vim.lsp').start") == 1
-    ]])
-
-    eq(true, exec_lua[[
-      return vim.fn.exists('v:lua.require"vim.lsp".start') == 1
-    ]])
-
-    eq(true, exec_lua[[
-      return vim.fn.exists("v:lua.require'vim.lsp'.start") == 1
-    ]])
-
-    eq(false, exec_lua[[
-      return vim.fn.exists("v:lua.require'vim.lsp'.unknown") == 1
-    ]])
-  end)
-
+end)
+
+describe('Vimscript function exists()', function()
+  it('can check a lua function', function()
+    eq(1, exec_lua[[
+      _G.test = function() print("hello") end
+      return vim.fn.exists('v:lua.test')
+    ]])
+
+    eq(1, funcs.exists('v:lua.require("mpack").decode'))
+    eq(1, funcs.exists("v:lua.require('mpack').decode"))
+    eq(1, funcs.exists('v:lua.require"mpack".decode'))
+    eq(1, funcs.exists("v:lua.require'mpack'.decode"))
+    eq(1, funcs.exists("v:lua.require('vim.lsp').start"))
+    eq(1, funcs.exists('v:lua.require"vim.lsp".start'))
+    eq(1, funcs.exists("v:lua.require'vim.lsp'.start"))
+    eq(0, funcs.exists("v:lua.require'vim.lsp'.unknown"))
+    eq(0, funcs.exists('v:lua.?'))
+  end)
 end)

test/functional/treesitter/fold_spec.lua

@@ -639,9 +639,7 @@ t2]])
       {1:│}t1                                     |
       {1:│}^                                       |
       {1:+}{2:+--  2 lines: # h2·····················}|
-      {3:~                                       }|
-      {3:~                                       }|
-      {3:~                                       }|
+      {3:~                                       }|*3
       {4:-- INSERT --}                            |
     ]]}
 
@@ -656,10 +654,7 @@ t2]])
       {1:-}^t1                                     |
       {1:-}# h2                                   |
       {1:│}t2                                     |
-      {3:~                                       }|
-      {3:~                                       }|
-      {3:~                                       }|
-      {3:~                                       }|
+      {3:~                                       }|*4
       1 line less; before #2  {MATCH:.*}|
     ]]}
   end)