Intermittent asset loading errors in Safari

p5.js version

1.9.4

What is your operating system?

macOS 14.5

Web browser and version

Safari 17.5

Actual Behavior

We've been experiencing severe problems using the web editor in class, specifically when loading images and fonts.
In a group of 20 students, there's never been a single session without those issues. Most of them are using Macbooks or iMacs.

The issue seems hard to reproduce, because a single sketch sometimes works, and sometimes doesn't. We've been calling it "p5.js server issues", maybe it's a regional thing as well – we're based in Austria/Europe.

This sketch fails for me right now in Safari 17.5: https://editor.p5js.org/groedl/sketches/OGg6QwaFu

The console reveals a CORS issue:

Some additional observations:

• The sketch works just fine in Chrome 126.
• The sketch works in Safari when using Private Mode.

The image seems to be loaded using fetch(), so I've tried to do that "manually" here: https://editor.p5js.org/groedl/sketches/86WqYZ9IR

This fails as well, but there are two cases which make the fetch() work:

1. Adding a trailing slash to the URL – found here: https://stackoverflow.com/a/39875236
2. Using mode: no-cors.
   Image Link

EDIT: These don't actually fix the issue. Case 1 works with fetch() but results in a 404. no-cors suceeds but returns no data (which is intended with no-cors).

Possibly related issues: #3062, #3089

Expected Behavior

Images should load without issues.

Steps to reproduce

Steps:

1. Run this sketch in Safari 17.5: https://editor.p5js.org/groedl/sketches/OGg6QwaFu

Start by running the linked sketch OGg6QwaFu in Safari 17.5 and comparing it with Chrome and Safari Private Mode. Inspect the reported CORS failure and review related issues #3062 and #3089; done means images and fonts load reliably in the affected Safari setup.