🚨 Error: Attempting to access a non-existant slide %s / %s NaN 7

[ampprojectbot]

Details

Error report: link
First seen: Apr 8, 2020
Frequency: ~ 61,503/day

Stacktrace

Error: Attempting to access a non-existant slide %s / %s NaN 7
    at Error (https://raw.githubusercontent.com/ampproject/amphtml/2004240001480/src/log.js:714:16)
    at createErrorVargs (https://raw.githubusercontent.com/ampproject/amphtml/2004240001480/src/log.js:308:20)
    at apply (https://raw.githubusercontent.com/ampproject/amphtml/2004240001480/src/log.js:323:18)
    at dev (https://raw.githubusercontent.com/ampproject/amphtml/2004240001480/extensions/amp-carousel/0.1/slidescroll.js:702:6)
    at showSlide_ (https://raw.githubusercontent.com/ampproject/amphtml/2004240001480/extensions/amp-carousel/0.1/slidescroll.js:758:25)
    at https://raw.githubusercontent.com/ampproject/amphtml/2004240001480/extensions/amp-carousel/0.1/slidescroll.js:603:6
    at callback (https://raw.githubusercontent.com/ampproject/amphtml/2004240001480/src/service/vsync-impl.js:470:16)
    at callTask_ (https://raw.githubusercontent.com/ampproject/amphtml/2004240001480/src/service/vsync-impl.js:426:8)

Notes

@rsimha modified src/log.js:308-311 in #21212 (May 16, 2019)
@erwinmombay modified src/log.js:323-324 in #6581 (Dec 20, 2016)
@rsimha modified extensions/amp-carousel/0.1/slidescroll.js:702-707 in #21212 (May 16, 2019)
@choumx modified extensions/amp-carousel/0.1/slidescroll.js:758-761 in #9863 (Jun 12, 2017)
@jridgewell modified src/service/vsync-impl.js:470-471 in #20836 (Feb 14, 2019)

Possible assignees: @jridgewell, @choumx

[caroqliu]

cc @jridgewell who made relevant changes recently and @alanorozco who is familiar with amp-carousel

[ampprojectbot]

A duplicate error report was linked to this issue (link)

[kristoferbaxter]

@zhouyx This error seems to be happening quite a bit.

[zhouyx]

amphtml/extensions/amp-carousel/0.1/slidescroll.js

Lines 691 to 699 in 552e6ed

	if (newSlideInView === undefined) {
	dev().error(
	TAG,
	'Attempting to access a non-existant slide %s / %s',
	newIndex,
	noOfSlides_
	);
	return false;
	}

Reported here when newSlideInView is undefined, and newIndexisNaN`

[zhouyx]

I wonder why newIndex = dev().assertNumber(newIndex); doesn't catch the NaN

[jridgewell]

typeof NaN === 'number'.