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Allow required modules to throw conditionally #1104
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cblappert
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Oct 28, 2017
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@hermanventer is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.
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Oct 31, 2017
Summary: Instead of delaying modules that throw conditionally, let the exception bubble up to the require call and then forget it (after emitting a warning). This allows more global state to be optimized and should be OK if it is understood that throwing an unhandled exception in module initialization code is not a supported scenario. Probably, the temporal point where the require call happens should contain a conditional throw statement, which would be equivalent to current behavior. For now, this causes invariants to fire in the serializer, probably because of bugs in how the state at the time of the exception is restored and presented to the throw statement. It is also an option to let the exception escape the require call itself and possibly bubble all the way to the top level. This would be more correct than the current behavior since it should match the runtime behavior of the unprepacked code. This too is currently buggy. It also a bit of performance concern because it uses much more saved state. Closes facebookarchive#1104 Differential Revision: D6189032 Pulled By: hermanventer fbshipit-source-id: 71c6352eddca4d88ae030fdcbfb76e7a39839e73
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Instead of delaying modules that throw conditionally, let the exception bubble up to the require call and then forget it (after emitting a warning). This allows more global state to be optimized and should be OK if it is understood that throwing an unhandled exception in module initialization code is not a supported scenario.
Probably, the temporal point where the require call happens should contain a conditional throw statement, which would be equivalent to current behavior. For now, this causes invariants to fire in the serializer, probably because of bugs in how the state at the time of the exception is restored and presented to the throw statement.
It is also an option to let the exception escape the require call itself and possibly bubble all the way to the top level. This would be more correct than the current behavior since it should match the runtime behavior of the unprepacked code. This too is currently buggy. It also a bit of performance concern because it uses much more saved state.
#976