🚨 Error: undefined is not an object (evaluating 'c.ampdoc')

[ampprojectbot]

Details

Error report: link
First seen: Apr 9, 2020
Frequency: ~ 1,349/day

Stacktrace

Error: undefined is not an object (evaluating 'c.ampdoc')
    at ampdoc (src/multidoc-manager.js:516:11)
    at closeShadowRoot_ (src/multidoc-manager.js:72:54)
    at extensions/amp-next-page/1.0/page.js:193:11
    at page (extensions/amp-next-page/1.0/service.js:418:19)
    at extensions/amp-next-page/1.0/service.js:411:13
    at hidePreviousPages_ (extensions/amp-next-page/1.0/service.js:344:8)
    at extensions/amp-next-page/1.0/service.js:335:24
    at extensions/amp-next-page/1.0/service.js:542:8
    at relativePos (extensions/amp-next-page/1.0/visibility-observer.js:310:29)
    at bottomSentinelPositionChanged_ (extensions/amp-next-page/1.0/visibility-observer.js:98:8)
    at position (src/service/position-observer/position-observer-worker.js:109:20)

Notes

@wassgha modified src/multidoc-manager.js:491-532 in #25629 (Dec 10, 2019)
@wassgha modified src/multidoc-manager.js:32-114 in #25629 (Dec 10, 2019)
@wassgha modified extensions/amp-next-page/1.0/page.js:184-193 in #26296 (Jan 23, 2020)
@wassgha modified extensions/amp-next-page/1.0/service.js:413-429 in #26296 (Jan 23, 2020)
@wassgha modified extensions/amp-next-page/1.0/service.js:410-411 in #26296 (Jan 23, 2020)
@wassgha modified extensions/amp-next-page/1.0/service.js:344-345 in #26296 (Jan 23, 2020)
@wassgha modified extensions/amp-next-page/1.0/service.js:328-335 in #25636 (Dec 10, 2019)
@wassgha modified extensions/amp-next-page/1.0/service.js:541-545 in #26296 (Jan 23, 2020)
@wassgha modified extensions/amp-next-page/1.0/visibility-observer.js:294-381 in #26778 (Apr 9, 2020)
@wassgha modified extensions/amp-next-page/1.0/visibility-observer.js:98-98 in #26778 (Apr 9, 2020)
@zhouyx modified src/service/position-observer/position-observer-worker.js:106-136 in #10813 (Sep 8, 2017)

Seen in:

• 08-22 Control (0050+1)
• 08-22 Nightly-Control (0050+1)
• 08-22 Stable (0050+1)

Possible assignees: @wassgha, @zhouyx

/cc @ampproject/release-on-duty

[rcebulko]

This appears predominantly on the domain eg-ru, and the few occurrences on other domains also appear to be Russian. All are on iPhone browser. I suspect this is some combination of publisher error (possibly relating to encoding?) or something Safari does with Russian sites or characters, as I've seen this pattern before of an unlikely error showing up only on Russion domains.

[ampprojectbot]

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