Remove local fork of acorn JS parser

[sbc100]

We currently have a local fork of acorn in-tree, but it would be more elegant to simply install it via npm.

Apparently there is a local patch that upstream don't want but a suggested workaround exists #11435

[ghost]

Hello, I think you wanna delete acornjs code in third_party directory and add to package.json.
Is it correct?

[sbc100]

Yes, but also we have a local patch which contains functionality which we would like to preserve. I believe @RReverser has suggested some way to get the desired behaviour without the local patch.

Thanks for the offer of help!

[ghost]

Can I ask a question?
First, I saw the history of built file of acorn(https://github.com/emscripten-core/emscripten/commits/master/third_party/acorn/dist/acorn.js)
But there is no changes.
So I saw the PR and I guess @kripken wanna add some error print. (acornjs/acorn#793)
If I write about this issue, I'll wrap this line(https://github.com/emscripten-core/emscripten/blob/master/tools/acorn-optimizer.js#L1302) with try~catch.
But now there is no code in this repository.
Where is the local patch?
Am I misunderstood about this issue or miss something..? 🤔

[RReverser]

Yeah it's quite hard to find the source change of Acorn, but it appears the built file was modified here

emscripten/third_party/acorn/dist/acorn.js

Lines 2770 to 2771 in 8c75547

	// XXX EMSCRIPTEN: add a quote of the error text, point to where
	// https://github.com/acornjs/acorn/pull/793

.

FWIW my suggestion was the following: as you can see, the errors raised by Acorn have pos and loc properties, so if someone wanted to, they could simply try-catch the error and use those properties to produce a message in an arbitrary format.

@TroyTae I think the easiest might be to just update Acorn code to latest upstream in Emscripten repo, and then look at the expected format vs retrieved one when running tests and wrap accordingly.

[kripken]

It's also possible we can just replace acorn and all tests would pass - I think we may have removed an overly-strict test for the error format. Worth opening a PR with just that, and seeing test results.

[ghost]

@RReverser Thank you! It seems history is lost after move directory 😅
As you said, error object has loc and pos, so maybe I can handle this.

@kripken Now I'm trying to do it. If we need some strict test, I'll write it :)