executor,functests: Add tests for :luado, also some fixes

Fixes:
1. Allocate space for the NUL byte.
2. Do not exclude last line from range.
3. Remove code for sandbox: it is handled earlier.
4. Fix index in new_line_transformed when converting NULs to NLs.
5. Always allocate new_line_transformed, but save allocated value.

src/nvim/viml/executor/executor.c

@@ -160,17 +160,19 @@ static int nlua_exec_lua_string(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
 static int nlua_exec_luado_string(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
 {
   const String *const str = (const String *)lua_touserdata(lstate, 1);
-  const linenr_T *const range = (const linenr_T *)lua_touserdata(lstate, 1);
+  const linenr_T *const range = (const linenr_T *)lua_touserdata(lstate, 2);
   lua_pop(lstate, 1);
 
 #define DOSTART "return function(line, linenr) "
 #define DOEND " end"
-  const size_t lcmd_len = str->size + (sizeof(DOSTART) - 1) + (sizeof(DOEND) - 1);
+  const size_t lcmd_len = (str->size
+                           + (sizeof(DOSTART) - 1)
+                           + (sizeof(DOEND) - 1));
   char *lcmd;
   if (lcmd_len < IOSIZE) {
     lcmd = (char *)IObuff;
   } else {
-    lcmd = xmalloc(lcmd_len);
+    lcmd = xmalloc(lcmd_len + 1);
   }
   memcpy(lcmd, S_LEN(DOSTART));
   memcpy(lcmd + sizeof(DOSTART) - 1, str->data, str->size);
@@ -186,7 +188,7 @@ static int nlua_exec_luado_string(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
     nlua_error(lstate, _("E5110: Error while creating lua function: %.*s"));
     return 0;
   }
-  for (linenr_T l = range[0]; l < range[1]; l++) {
+  for (linenr_T l = range[0]; l <= range[1]; l++) {
     if (l > curbuf->b_ml.ml_line_count) {
       break;
     }
@@ -198,24 +200,15 @@ static int nlua_exec_luado_string(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
       break;
     }
     if (lua_isstring(lstate, -1)) {
-      if (sandbox) {
-        EMSG(_("E5112: Not allowed in sandbox"));
-        lua_pop(lstate, 1);
-        break;
-      }
       size_t new_line_len;
-      const char *new_line = lua_tolstring(lstate, -1, &new_line_len);
-      char *const new_line_transformed = (
-          new_line_len < IOSIZE
-          ? memcpy(IObuff, new_line, new_line_len)
-          : xmemdupz(new_line, new_line_len));
-      new_line_transformed[new_line_len] = NUL;
+      const char *const new_line = lua_tolstring(lstate, -1, &new_line_len);
+      char *const new_line_transformed = xmemdupz(new_line, new_line_len);
       for (size_t i = 0; i < new_line_len; i++) {
-        if (new_line_transformed[new_line_len] == NUL) {
-          new_line_transformed[new_line_len] = '\n';
+        if (new_line_transformed[i] == NUL) {
+          new_line_transformed[i] = '\n';
         }
       }
-      ml_replace(l, (char_u *)new_line_transformed, true);
+      ml_replace(l, (char_u *)new_line_transformed, false);
       changed_bytes(l, 0);
     }
     lua_pop(lstate, 1);

test/functional/lua/commands_spec.lua

@@ -63,3 +63,48 @@ describe(':lua command', function()
     eq(42, funcs.luaeval('gvar'))
   end)
 end)
+
+describe(':luado command', function()
+  it('works', function()
+    curbufmeths.set_lines(0, 1, false, {"ABC", "def", "gHi"})
+    eq('', redir_exec('luado lines = (lines or {}) lines[#lines + 1] = {linenr, line}'))
+    eq({'ABC', 'def', 'gHi'}, curbufmeths.get_lines(0, -1, false))
+    eq({{1, 'ABC'}, {2, 'def'}, {3, 'gHi'}}, funcs.luaeval('lines'))
+
+    -- Automatic transformation of numbers
+    eq('', redir_exec('luado return linenr'))
+    eq({'1', '2', '3'}, curbufmeths.get_lines(0, -1, false))
+
+    eq('', redir_exec('luado return ("<%02x>"):format(line:byte())'))
+    eq({'<31>', '<32>', '<33>'}, curbufmeths.get_lines(0, -1, false))
+  end)
+  it('stops processing lines when suddenly out of lines', function()
+    curbufmeths.set_lines(0, 1, false, {"ABC", "def", "gHi"})
+    eq('', redir_exec('2,$luado runs = ((runs or 0) + 1) vim.api.nvim_command("%d")'))
+    eq({''}, curbufmeths.get_lines(0, -1, false))
+    eq(1, funcs.luaeval('runs'))
+  end)
+  it('works correctly when changing lines out of range', function()
+    curbufmeths.set_lines(0, 1, false, {"ABC", "def", "gHi"})
+    eq('\nE322: line number out of range: 1 past the end\nE320: Cannot find line 2',
+       redir_exec('2,$luado vim.api.nvim_command("%d") return linenr'))
+    eq({''}, curbufmeths.get_lines(0, -1, false))
+  end)
+  it('fails on errors', function()
+    eq([[Vim(luado):E5109: Error while creating lua chunk: [string "<VimL compiled string>"]:1: unexpected symbol near ')']],
+       exc_exec('luado ()'))
+    eq([[Vim(luado):E5111: Error while calling lua function: [string "<VimL compiled string>"]:1: attempt to perform arithmetic on global 'liness' (a nil value)]],
+       exc_exec('luado return liness + 1'))
+  end)
+  it('fails in sandbox when needed', function()
+    curbufmeths.set_lines(0, 1, false, {"ABC", "def", "gHi"})
+    eq('\nE48: Not allowed in sandbox: sandbox luado runs = (runs or 0) + 1',
+       redir_exec('sandbox luado runs = (runs or 0) + 1'))
+    eq(NIL, funcs.luaeval('runs'))
+  end)
+  it('works with long strings', function()
+    local s = ('x'):rep(100500)
+    eq('', redir_exec(('luado return "%s"'):format(s)))
+    eq({s}, curbufmeths.get_lines(0, -1, false))
+  end)
+end)