sourceURL confusion

[matthewp]

Hey @guybedford, Firefox recently fixed a bug that prevented evaled source from showing up in the developer tools. When I load the es6ml tests in Nightly it doesn't show up as expected and I believe it's because of this (just one example):

//# sourceMappingURL=<compileOutput>
//# sourceURL=http://localhost:8000/test/loads/c.js
//# sourceURL=http://localhost:8000/test/loads/c.js!eval
//# sourceMappingURL=data:application/json;base64,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

Why are there two sourceURLs?

[matthewp]

This was the FF bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1107541

[guybedford]

That is great to know - ok will check this out. PRs welcome too.

[guybedford]

The second sourceURL was added by #256.

[guybedford]

Ok I've added 95357f8 which removes the duplicate sourceURL.

For the sourceMappingURL duplicate I've posted google/traceur-compiler#1595.

[matthewp]

Awesome! Left a console.log in though: 95357f8#diff-5232188b8887c5e2752c803fd8ead1feR1111

[guybedford]

Thanks I've fixed that.

[matthewp]

Ok, so it looks like that wasn't the cause after all. Might be the source maps. I'll look into it myself and see what I can find. Here's what it looks like though, notice the sources on the left:

[guybedford]

Thanks, any help is appreciated.

[guybedford]

Just a heads up - I'm aiming for a release tomorrow, so if you make some progress please do let me know.

[matthewp]

I won't have anything in that timeframe.

[guybedford]

No worries at all, and thanks for letting me know. We can post a patch anytime.

[guybedford]

@matthewp with 96b436a, there are no longer any duplicates.

[guybedford]

@matthewp did you make any further progress on this?

[matthewp]

Hey @guybedford I do intend to look into this more but haven't done so yet.

[matthewp]

Hey @guybedford I did some more research and it seems that in firefox the #sourceURL= comment must be at the end of the file. Currently __eval wraps all code with }).call(__global);. What do you think about stripping out the sourceURL comment and placing it at the end of the eval? Is that too hacky?