Suspending inside a constructor outside of strict mode#13200
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acdlite merged 2 commits intofacebook:masterfrom Jul 13, 2018
Merged
Suspending inside a constructor outside of strict mode#13200acdlite merged 2 commits intofacebook:masterfrom
acdlite merged 2 commits intofacebook:masterfrom
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Outside of strict mode, suspended components commit in an incomplete state, then are synchronously deleted in a subsequent commit. If a component suspends inside the constructor, it mounts without an instance. This breaks at least one invariant: during deletion, we assume that every mounted component has an instance, and check the instance for the existence of `componentWillUnmount`. Rather than add a redundant check to the deletion of every class component, components that suspend inside their constructor and outside of strict mode are turned into empty functional components before they are mounted. This is a bit weird, but it's an edge case, and the empty component will be synchronously unmounted regardless.
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cyan33
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Jul 12, 2018
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Seems a bit hacky but glad it fixes the issue in non-strict mode.
sebmarkbage
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Jul 13, 2018
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| if ( | ||
| sourceFiber.tag === ClassComponent && | ||
| workInProgress.stateNode === null |
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Let's use current === null because we don't want to fire componentWillUnmount unless we fired componentDidMount.
In non-strict mode, suspended components commit, but their lifecycles should not fire.
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sebmarkbage
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Outside of strict mode, suspended components commit in an incomplete state, then are synchronously deleted in a subsequent commit. If a component suspends inside the constructor, it mounts without an instance.
This breaks at least one invariant: during deletion, we assume that every mounted component has an instance, and check the instance for the existence of
componentWillUnmount.Rather than add a redundant check to the deletion of every class component, components that suspend inside their constructor and outside of strict mode are turned into empty functional components before they are mounted. This is a bit weird, but it's an edge case, and the empty component will be synchronously unmounted regardless.