Fix commonjs module.exports= merging#27368
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sandersn merged 1 commit intorelease-3.1from Sep 26, 2018
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I'm surprised we haven't seen more of this; I suspect it's because the mixed `module.exports=` + `export.foo=` pattern isn't that common. However, it'll happen any time that the exported symbol is unknown; getCommonJsExportEquals blithely clones unknownSymbol and proceeds to stick the `exports.foo=` properties onto it. This causes problems later, because the compiler checks for unknownSymbol with `===`. The fix is to not stick properties onto a clone of unknownSymbol. This makes the correct errors appear and removes the crash.
sheetalkamat
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Sep 26, 2018
sandersn
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I'm surprised we haven't seen more of this; I suspect it's because the mixed `module.exports=` + `export.foo=` pattern isn't that common. However, it'll happen any time that the exported symbol is unknown; getCommonJsExportEquals blithely clones unknownSymbol and proceeds to stick the `exports.foo=` properties onto it. This causes problems later, because the compiler checks for unknownSymbol with `===`. The fix is to not stick properties onto a clone of unknownSymbol. This makes the correct errors appear and removes the crash.
sandersn
added a commit
that referenced
this pull request
Sep 26, 2018
I'm surprised we haven't seen more of this; I suspect it's because the mixed `module.exports=` + `export.foo=` pattern isn't that common. However, it'll happen any time that the exported symbol is unknown; getCommonJsExportEquals blithely clones unknownSymbol and proceeds to stick the `exports.foo=` properties onto it. This causes problems later, because the compiler checks for unknownSymbol with `===`. The fix is to not stick properties onto a clone of unknownSymbol. This makes the correct errors appear and removes the crash.
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Whenever the exported symbol is unknown getCommonJsExportEquals blithely clones unknownSymbol and proceeds to stick the
exports.foo=properties onto it.This causes problems later, because the compiler checks for unknownSymbol with
===. The fix is to not stick properties onto a clone of unknownSymbol. This makes the correct errors appear and removesthe crash. Maybe we should consider supporting this pattern [1], but for now I think it's fine to issue an error on the unknown property.
Fixes #27025
[1] Call it "speculative export of a supposedly-global expando object", I guess. Makes it sound really appetising.