setProps performance issues leads to RangeError: Maximum call stack size exceeded

[AlexandreBonaventure]

Version

1.0.0-beta.26

Reproduction link

https://github.com/AlexandreBonaventure/repro-test-utils-setProps

Steps to reproduce

git clone https://github.com/AlexandreBonaventure/repro-test-utils-setProps > yarn install > yarn test:unit

What is expected?

No performance issue across all tests

What is actually happening?

Performance is affected when using more and more messages in vue-i18n

---

Hello,
I stumbled upon a performance issue when using wrapper.setProps and vue-i18n. For some reasons, tests are running slower and slower with the increased amount of entries (0 -> 3000 lines) in vue-i18n messages (translations), eventually ending up in a RangeError. I know some people will tell me that I could either mock or get rid of vue-i18n in my test, but it is very convenient to do so to track untranslated messages in a vue app. At my company we are using it extensively. Moreover, I don't think we should experience this kind a performance issue anyway and that let me believe this is a code smell in the way test-utils reorders dependencies.

without message + with 1000 lines messages

with 3000 lines messages

NB: using a wrapper factory instead of setProps is fixing the issue as well.
Thanks

[eddyerburgh]

This issue is caused by the implementation of synchronous updating. This will be fixed after the next patch of Vue is released (Vue 2.5.18). In the meantime you can run your tests with sync set to false:

const wrapper = mount(TestComponent, {
  sync: false
})