bug(iOS): `scrollTo(edge)` is failing when there's an overlay view although the view is scrollable

[asafkorem]

What happened?

Test Failed: View is not scrollable at the given start point. Start point (view coordinates): {137.19999999999999, 24}
- Full error: View is not visible around point.
- view point: {137.19999999999999, 24}
- visible bounds: {{116.5, 0}, {414, 48}}
- view bounds: {{0, 0}, {414, 48}}
---
Error: Error Domain=DetoxErrorDomain Code=0 "View “<RCTCustomScrollView: 0x7fcbfb957600>” is not visible: View does not pass visibility percent threshold (100)" UserInfo={NSLocalizedDescription=View “<RCTCustomScrollView: 0x7fcbfb957600>” is not visible: View does not pass visibility percent threshold (100)}
----
More about scroll action API here: https://wix.github.io/Detox/docs/api/actions-on-element/#scrolloffset-direction-startpositionx-startpositiony

See internal support case (Wix employees only): https://wix.slack.com/archives/C1Y4D9BK8/p1670500144347379

The view should be scrollable, and the error is coming from here: https://github.com/wix/Detox/blob/master/detox/ios/Detox/Utilities/UIView%2BDetoxUtils.m#L299

I suspect that there's a wrong calculation on this test, and this might be a redundant check also, because a visible area is already calculated.
This error should be solved on the XCUITest transition also, which may affect the priority of this bug-fix.

[noomorph]

#2362 I guess this is issue no. 1, right? (should be able to scroll tab bar strip with a gradient overlay)

[paulrostorp]

We are also facing this issue, is there any known workaround ?

[noomorph]

@paulrostorp regarding workarounds – I can't remember precisely but removing pointerEvents: none (→ this forces you to somehow to re-layout elements) might work. If the overlay is not a complete one then you can start scrolling from a custom x,y position.

@asafkorem do you remember when we decided to try to fix this?

[paulrostorp]

Thanks for the quick reply, I'll play around with that

[effektsvk]

I made a quick workaround by repeatedly scrolling to a certain direction until it fails. I have a custom class where this.scrollView is just element(by.id('scrollViewId')). I didn't test it with refresh control, so I'm not sure if it works with that. Also, the values in scroll() can be fine-tuned, this is just first thing that worked.

scrollToTop = async (): Promise<void> => {
  try {
    await this.scrollView.scroll(200, 'up', 0.5, 0.5)
    await this.scrollToTop()
  } catch (error) {
    console.log('scrolled to top')
  }
}