Amphtml: the height of amp-list will be resized with some random height when user wants to navigate to another page

[leonalicious]

Hi guys, we notice since the version released of v1810052256480, the height of amp-list will be resized with some random height when user wants to navigate to another page, can you please check on this ? appreciate your guys assistance on this

to: @choumx @aghassemi

[aghassemi]

/cc @cathyxz as well

[leonalicious]

https://github.com/ampproject/amphtml/pull/18148
i think this is the PR who is causing the issue, hope it helps

[choumx]

Thanks for the report (and the animated GIF).

This is an interesting one. It's caused by placeholder resizing in #18148. The placeholder animation is 690px and the amp-list is layout=fill which means it has a height of 1px at layoutCallback.

Since 690 > 1, the amp-list requests a height change to 690. However, this remains queued while the amp-list finishes rendering (3000px+ height). So the amp-list's resource still has a pending change-size (getPendingChangeSize()) of 690px.

This change size to 690px is finally triggered from a focus event listener in focus-history.js, which eventually triggers the flushing of the pending change-size.

To fix this, we should call resetPendingChangeSize() after render.

[leonalicious]

this is another more serious issue that we have been facing on ShopCart Page List ~

[erwinmombay]

rollback should be in canary now

[leonalicious]