--use_strict does not work with script and REPL, only work with stdin and eval

[loynoir]

Background

--use_strict is not my use case.

I'm just investigating --use_strict.

Description

--use_strict works with stdin

$ cat actual.cjs | node --use_strict
{ isStrict: [ true, true ] }

--use_strict works with eval

$ node --use_strict -e "$(cat actual.cjs)"
{ isStrict: [ true, true ] }

--use_strict not works file

$ node --use_strict actual.cjs
{ isStrict: [ false, false ] }

--use_strict not works REPL

$ node --use_strict
Welcome to Node.js v18.15.0.
Type ".help" for more information.
> require('./actual.cjs')
{ isStrict: [ false, false ] }
{}

Version

v18.15.0

Platform

No response

Subsystem

No response

What steps will reproduce the bug?

==> actual.cjs <==

#!/usr/bin/env -S node --use_strict


var isStrict = (function () {
  var a = !this;

  var b;
  try {
    eval(`with({}){}`);
    b = false;
  } catch {
    b = true;
  }

  return [a, b];
})();

console.log({ isStrict });

==> expected.cjs <==

#!/usr/bin/env -S node
"use strict";

var isStrict = (function () {
  var a = !this;

  var b;
  try {
    eval(`with({}){}`);
    b = false;
  } catch {
    b = true;
  }

  return [a, b];
})();

console.log({ isStrict });

How often does it reproduce? Is there a required condition?

No response

What is the expected behavior? Why is that the expected behavior?

$ node expected.cjs             
{ isStrict: [ true, true ] }
$ cat actual.cjs | node --use_strict
{ isStrict: [ true, true ] }
$ node --use_strict -e "$(cat actual.cjs)"
{ isStrict: [ true, true ] }

should be

• or fix cli flag --use_strict

• or remove cli flag --use_strict deprecate --use_strict #6429

• or show message

$ node --use_strict actual.cjs
node:internal/modules/cjs/loader:xxx
  throw err;
  ^

Error:  The --use_strict flag does not work with script and REPL, only work with stdin and eval
    at xxx (node:internal/modules/cjs/loader:xxx:xxx) {
  code: 'INVALID_FLAG',
  requireStack: []
}

Node.js v18.15.0

What do you see instead?

--use_strict not works file

$ node --use_strict actual.cjs
{ isStrict: [ false, false ] }

--use_strict not works REPL

$ node --use_strict
Welcome to Node.js v18.15.0.
Type ".help" for more information.
> require('./actual.cjs')
{ isStrict: [ false, false ] }
{}

Additional information

Seems related

#4196

#6429

[bnoordhuis]

So, I'm reasonably sure this is caused by the use of v8::ScriptCompiler::CompileFunction() vs. v8::Script::Run(). The former is used to evaluate require'd code (that includes the main script), the latter for -e / --eval and also vm.runInContext() and friends.

You can see it for yourself with these two test scripts:

// Flags: --use_strict
with ({}) {} // no exception

vs.

// Flags: --use_strict
require("vm").runInThisContext(`with ({}) {}`) // throws

v8::ScriptCompiler::CompileFunction() does look at the --use_strict flag in v8::internal::Compiler::GetWrappedFunction() but I still have every reason to believe this is a V8 bug, not a Node.js bug.

node/deps/v8/src/codegen/compiler.cc

Line 3656 in 8244e6c

LanguageMode language_mode = construct_language_mode(v8_flags.use_strict);

[targos]

Duplicate of #30039 ?

[bnoordhuis]

Oh, indeed! I'll go ahead and close this one then.