Bug: ModuleEvaluation had breaking change to not return completion value

[bmeck]

Somehow missed this change a while back

This value is used by Node in order to create some reflection https://github.com/nodejs/node/blob/master/lib/internal/modules/esm/create_dynamic_module.js

[domenic]

Can you explain the issue in more detail? Remember that the spec has a blanket clause allowing returning JS values which implicitly gives you a normal completion for that value.

[domenic]

Can you explain the issue in more detail? Remember that the spec has a blanket clause allowing returning JS values which implicitly gives you a normal completion for that value.

[ljharb]

Can you link to the part of the spec in question?

[ljharb]

Can you link to the part of the spec in question?

[bmeck]

@domenic does that apply to concrete methods? I thought that concrete methods needed to return the value the spec says they return.

https://www.ecma-international.org/ecma-262/6.0/index.html#sec-moduleevaluation states that it completes with result

newer spec https://tc39.github.io/ecma262/#sec-moduleevaluation completes with undefined

[bmeck]

@domenic does that apply to concrete methods? I thought that concrete methods needed to return the value the spec says they return.

https://www.ecma-international.org/ecma-262/6.0/index.html#sec-moduleevaluation states that it completes with result

newer spec https://tc39.github.io/ecma262/#sec-moduleevaluation completes with undefined

[domenic]

Yes, it applies to everything. "Concrete methods" are just abstract operations that conform to some interface.

[domenic]

Yes, it applies to everything. "Concrete methods" are just abstract operations that conform to some interface.

[bmeck]

@domenic it still looks like this changed from result to undefined.

[bmeck]

@domenic it still looks like this changed from result to undefined.

[domenic]

Right, that makes sense, since no caller uses that value.

[domenic]

Right, that makes sense, since no caller uses that value.

[bmeck]

@domenic maybe, I'm not sure on this though since we do have some exposure of the result being used by a host platform. From a spec point of view this seems fine if we don't consider host usage, but I'm pointing particularly that a host is using this result.

[bmeck]

@domenic maybe, I'm not sure on this though since we do have some exposure of the result being used by a host platform. From a spec point of view this seems fine if we don't consider host usage, but I'm pointing particularly that a host is using this result.

[ljharb]

This seems more like a layering issue than a spec bug then.

[ljharb]

This seems more like a layering issue than a spec bug then.

[littledan]

If there are some hosts which concretely point to an abstract algorithm and say, this operation of mine calls that abstract operation and returns the result, it may be helpful for that host's documentation to have stability in the JS spec. This is sort of a layering issue, like for HTML calling into abstract operations.

I'm not sure what abstract operation you're talking about (I don't see one called ModuleEvaluation) and what host API is referring to that. I'm also not sure which spec change made a difference. It would be helpful if you could give these details.

[littledan]

If there are some hosts which concretely point to an abstract algorithm and say, this operation of mine calls that abstract operation and returns the result, it may be helpful for that host's documentation to have stability in the JS spec. This is sort of a layering issue, like for HTML calling into abstract operations.

I'm not sure what abstract operation you're talking about (I don't see one called ModuleEvaluation) and what host API is referring to that. I'm also not sure which spec change made a difference. It would be helpful if you could give these details.

[bmeck]

@littledan it used to be called ModuleEvaluation now it is just Evaluate, I have links above. I chose to use the original name prior to some reorganization that went on since that had the behavior desired and is the name of the link to the section still.

Evaluate on Source Text Module Records is the concrete algorithm in question. This corresponds to the API in v8 for v8::Module::Evaluate

[bmeck]

@littledan it used to be called ModuleEvaluation now it is just Evaluate, I have links above. I chose to use the original name prior to some reorganization that went on since that had the behavior desired and is the name of the link to the section still.

Evaluate on Source Text Module Records is the concrete algorithm in question. This corresponds to the API in v8 for v8::Module::Evaluate

[littledan]

Ah, sorry, missed that, thanks for the references!

[littledan]

Ah, sorry, missed that, thanks for the references!