computed function executed with in an error

[keelii]

Vue version

3.4.24

Link to minimal reproduction

https://play.vuejs.org/#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

Steps to reproduce

click the hello world text in playground.

What is expected?

Either return undefined or throw an exception in every computed function executed.

What is actually happening?

first time, it throw a Error
second time, it return an undefined

System Info

No response

Any additional comments?

No response

[keelii]

if (
  (!self._cacheable || self.effect.dirty) &&
  hasChanged(self._value, (self._value = self.effect.run()!))
) {
  triggerRefValue(self, DirtyLevels.Dirty)
}

When i check the source code, self.effect.dirty maybe should assigned to true when effect.run throw an exception ?

[yyx990803]

Your example is a bit contrived as it unlikely happens in real code - but in this specific case it's almost expected behavior because on repeated clicks nothing has changed and the computed will just cache previous value and not even execute the getter again. And if a computed errors on initial evaluation, the app just crashes.

A more practical case would be a computed that conditionally throws error on state change: example

This currently breaks in 3.4 but will recover and repeatedly throw the error in 3.5 (this is the behavior in the current minor branch). So closing this for now as it will be addressed when 3.5 is out.