"An error occurred trying to load the resource" - error in network tab when no visible missing tile

[Vasilia-Themis]

Checklist

• I've looked at the documentation to make sure the behavior isn't documented and expected.
• I'm sure this is an issue with Leaflet, not with my app or other dependencies (Angular, Cordova, React, etc.).
• I've searched through the current issues to make sure this hasn't been reported yet.
• I agree to follow the Code of Conduct that this project adheres to.

Steps to reproduce

Bug reproduced on a number of different iOS devices
Unable to reproduce on Android or desktop

• Go to https://leafletjs.com/ on mobile iOS Safari
• Use Safari dev tools to monitor network traffic (how to do this on mobile - https://www.headspin.io/blog/tips-and-tricks-for-using-inspect-element-on-ios)
• Go to the example map and pan around a lot quickly zooming in and out
• In the network tab you will see: data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs= or similar
• The preview will say "An error occurred trying to load the resource"

Expected behavior

• I do not expect to see "An error occurred trying to load the resource" in the dev tools network tab

Current behavior

• In the network tab you will see: data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs= or similar
• The preview will say "An error occurred trying to load the resource"

Minimal example reproducing the issue

https://plnkr.co/edit/YiUS1lMzYAIZwLUs?preview

Environment

• Leaflet version: Leaflet 1.9.4
• Browser (with version): Safari iOS 16.2
• OS/Platform (with version): iOS 16.2

[IvanSanchez]

That URL is the one for a 1x1 transparent gif image (gosh, knowing that fact makes me a nerd). In the leaflet codebase it lives at L.Util.emptyImageURL, and is set into tiles at:

Leaflet/src/layer/tile/TileLayer.js

Line 242 in 39ce117

tile.src = Util.emptyImageUrl;

It has no ill effect besides that warning. It's done for historical reasons: destroying a non-completely-loaded HTMLImageElement used to crash the Android stock browser. See #137 and #5615 .

Not sure if we want to revisit this?

[Vasilia-Themis]

Thank you for the quick reply @IvanSanchez. It seems to be linked with the publishing of a tileerror event on the TileLayer, which is causing us problems. This only happens intermittently so I'm not confident of the link. Does that sound plausible?

[IvanSanchez]

But this is a non-issue anyway. The Safari dev tools are failing to display an image coming from a data: URL, which is different than "an image is causing an error" (since there are no errors/warnings in your console anyway).

If you have something about tileerror, then that's a different issue. Let's stick to this one.