Problems with emcc v3.1.31 in combination with -sMODULARIZE -sEXPORT_ES6

[WolfgangDrescher]

Currently buildToolkit is not compatible with emcc v3.1.31 when running with -s MODULARIZE=1 -s EXPORT_ES6=1.

The JS build will contain "use strict"; inside the async return function of createVerovioModule():

var createVerovioModule = (() => {
  var _scriptDir = import.meta.url;
  
  return (
async function(config) {
  var createVerovioModule = config || {};

"use strict";var Module=...

This will run into:

Illegal 'use strict' directive in function with non-simple parameter list (Note that you need plugins to import files that are not JavaScript)

I will check if we need additional flags such as -sSTRICT or -sSTRICT_JS or if we need to wait for the next emcc release.

There seems to be already a merged pull request related to this: emscripten-core/emscripten#18614. As well as related issues: emscripten-core/emscripten#18610, emscripten-core/emscripten#18620.

[lpugin]

Thanks. Hopefully this will be fixed when we make the next release. If not we can build it with an earlier version that still works.

[WolfgangDrescher]

I was able to compile it with -s STRICT_JS=0. This makes sense as ES module are always "use strict"; anyways. But the current fix in emscripten will remove -s STRICT_JS=1 as default value when MODULARIZE or EXPORT_ES6 is set. So we should be fine with the next emcc release.

When this is not released yet for the next verovio release I can create a small PR: https://github.com/WolfgangDrescher/verovio/tree/fix-3238

Or we can implement something like this:

https://github.com/mackyle/sqlite/blob/a5de80effaf1e60d110e894a28bdf4144aff5311/ext/wasm/GNUmakefile#L527-L533

If not we can build it with an earlier version that still works.

It looks like older version had the same problem but I only noticed it now because a dependency is more strict with strict mode (either Rollup.js oder Vite, but I'm not sure about this yet).

[lpugin]

@WolfgangDrescher any update on this?

[WolfgangDrescher]

Verovio v3.15.0 was most likely build with a recent version of emcc where the linked PRs are already merged. verovio-module.mjs now looks like this:

var createVerovioModule = (() => {
  var _scriptDir = import.meta.url;
  
  return (
async function(createVerovioModule = {})  {

var Module=...

This looks good now, but I did not test it again. I will close this issue and reopen if I run into this problem again.

[lpugin]

Great! Many thanks for keeping an eye on this. It is all very helpful.