Annotations inappropriately disappear en masse based on zoom

[friedbunny]

On master circa 10a4405 (pre-ios-v4.0.0), zooming in/out of a map with 10,000 sprite annotations can cause virtually every annotation to inappropriately disappear.

1. Add 10,000 sprite annotations in iosapp.
2. Zoom several levels in and out — annotations will disappear and then mostly never reappear.

Check out this video for a demonstration.

If you quickly zoom in to ~z11 and then out to ~z4, it’s possible to have a single annotation remaining (out of the 10k that should be visible). In general, this appears to be happening within individual tiles.

Annotations have gonezo.

/cc @mapbox/gl-core @akitchen @fabian-guerra @lilykaiser

[1ec5]

Does this issue reproduce only with annotations, or does it also reproduce with symbols in a symbol layer? Collision detection was overhauled in #10436 on master; could that be related?

[ChrisLoer]

Collision detection was overhauled in #10436 on master; could that be related?

Yeah, I think so, although I'm not super familiar with how Annotations are implemented -- basically a SymbolAnnotation should behave like an icon feature, right? @ansis, this makes me think "inappropriate CrossTileSymbolIndex duplicate detection" -- does this ring any bells with the work you're doing right now?

[jfirebaugh]

Symbol annotations use a symbol layer with "icon-allow-overlap": true and "icon-ignore-placement": true.

Another potential culprit is ac32b41.

[ChrisLoer]

I can reproduce this on the commit before ac32b41.

[kkaefer]

I believe ac32b41 isn't at fault here, since I can observe the same behavior in the commit immediately preceding it.

[ChrisLoer]

Bisected to #10436.

[ChrisLoer]

#10899 appears to fix this (I've tested on macosapp and a simulated iphone 6s so far).