Ensure error is actually visible if wasm fails to load

[lukaslueg]

cargo-web/src/wasm_runtime_standalone.js

Line 46 in 8b9b5da

console.log( "Error loading Rust wasm module '{{{module_name}}}':", error );

This should be error.toString(), not just error to ensure that the error message is actually printed. If the object can't be cloned, the message will be "<unavailable>", which is not helpful at all.

[Pauan]

If the object can't be cloned, the message will be "", which is not helpful at all.

Is that true with Firefox extensions? I know Firefox in general supports printing error objects without any problem (they're not cloned, they're just printed).

[lukaslueg]

At least in the context of loading an extension, the error is always <unavailable>, unless it's manually turned into a string first.

[koute]

At least in the context of loading an extension, the error is always <unavailable>, unless it's manually turned into a string first.

That sounds to me like a bug of console.log. Are you sure it isn't a bug?

[Pauan]

@koute Yeah, it's a bug with Firefox Extensions: using console.log with an Error works fine in Firefox, Chrome, and Chrome Extensions (just not in Firefox Extensions):

https://bugzilla.mozilla.org/show_bug.cgi?id=1327280
https://bugzilla.mozilla.org/show_bug.cgi?id=1462501
https://bugzilla.mozilla.org/show_bug.cgi?id=1393026

Technically it's an intentional feature omission (not a bug), but it sounds like they have plans to fix it regardless.

[lukaslueg]

We could have the shim try to avoid the situation, yet as far as I'm concerned this can be closed.

[Pauan]

@lukaslueg Personally, I think it's reasonable for the web-extension runtime to use .toString(), since this is an issue only with Firefox extensions. Other runtimes would be unchanged.

It would only affect the wasm loading logic, other errors might still show up as <unavailable>. So the impact is minimized.

Do you want to make a PR for that, or should I?

[lukaslueg]

Probably a one-line change, yet I wont get around doing it :-) Am Do., 6. Dez. 2018 um 12:01 Uhr schrieb Pauan <notifications@github.com>:

…

@lukaslueg <https://github.com/lukaslueg> Personally, I think it's reasonable for the web-extension runtime to use .toString(), since this is an issue only with Firefox extensions. Other runtimes would be unchanged. It would only affect the wasm loading logic <https://github.com/koute/cargo-web/blob/6cb5ef63db4738c5800d733c3bdc901cabb437d2/src/wasm_runtime_web_extension.js#L21>, other errors might still show up as <unavailable>. So the impact is minimized. Do you want to make a PR for that, or should I? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#147 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ADALoEWUUVL4LXY1kmcPGIiGJdM2faN9ks5u2PkIgaJpZM4XyJRI> .

[koute]

Well, I'm fine with adding the .toString() if it's only in the context of the extension-specific runtime. We can always remove it later when the issue is fixed in Firefox.

[Pauan]

This was fixed by #162

[koute]

Published as 0.6.22