[🐞] v2: uncaught promise caused by setTimeout, style object, and computed

[thejackshelton]

Which component is affected?

Qwik Runtime

Describe the bug

There is an uncaught promise when we try to introduce autoplay behavior (like in a carousel component) in v2. This is a regression from v1.

Reproduction

https://github.com/thejackshelton/uncaught-promise-timeout-repro/edit/main/README.md

Steps to reproduce

Reproduction Steps

1. pnpm install
2. pnpm dev
3. open http://localhost:5173
4. open console
5. click the autoplay button
6. see an uncaught promise error in the console

Expected Behavior

The carousel should autoplay without throwing an uncaught promise error.

System Info

System:
    OS: macOS 26.0
    CPU: (16) arm64 Apple M4 Max
    Memory: 835.52 MB / 48.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 24.9.0 - /Users/jackshelton/.nvm/versions/node/v24.9.0/bin/node
    Yarn: 1.22.22 - /usr/local/bin/yarn
    npm: 11.6.0 - /Users/jackshelton/.nvm/versions/node/v24.9.0/bin/npm
    pnpm: 10.19.0 - /Users/jackshelton/.nvm/versions/node/v24.9.0/bin/pnpm
    bun: 1.1.7 - /Users/jackshelton/.bun/bin/bun
    Deno: 2.1.4 - /opt/homebrew/bin/deno
  Browsers:
    Brave Browser: 141.1.83.120
    Chrome: 141.0.7390.123
    Firefox: 144.0.2
    Safari: 26.0
  npmPackages:
    typescript: 5.4.5 => 5.4.5 
    undici: * => 7.16.0 
    vite: 7.1.11 => 7.1.11

Additional Information

The uncaught promise error is thrown after the setInterval time.

Removing the signal read in the object style property prevents the uncaught promise error.

[wmertens]

Playground repro: https://qwikdev-build-v2.qwik-8nx.pages.dev/playground/#f=7Vg9j9NAEO3vVywrhIJkmwTREB1OQZWKq2gQhbnYJOhEcvEFCUX577zZ%2BfCskys46bqrEsezs7NvZt68jSua99MPdh4KcaiAgp7ycqOflELoe0okinPXf%2BnsmWc2PVIr0KdvBnvOClt%2BHZbqiM7Ni%2FD6SjIfc40Ux9jfNuh3zCuLHYkYN8%2Fn3KamvMT7w6bUxSVxHN7EK%2BCm%2FtMhR0vhnMDb9DQrdmDIucCA9ECMNL%2BpWcYhqg8pE9d7cDURoSXoXkcIsViHN2iAROU37f4r%2BHIx14l7siqjJJL%2FIRp4N3QnXXPXtziPM3QO2XTgLi7eFEyV2S0WYUaoDG4SNy5psIC%2FL7rh6EKAGEAqVmHb8d478YkZQyjQErH0W1bY4NBy4MQ8bmvJ0%2FyRvCRPhgbVFDxkDpJkgv9UJ4PwhFiqJ7qVyUYebJOjSEGPPPtT%2FRl1SRS80SK0ROAYQuKjmdGmCxPts7fCGhKEBtys%2FjRQS0vgkyDPeMZQhqwL%2FRaaAHCTEmhUdiT41y2Ewm2DIPsAumwOP9cPlGpSUObFZ9VnYEAw7TReH9ZgmBbM3nRAlkTkUiBOikgParCza5zCWY6qJpwdmlIjsRRhNp1O5dmq48IIPSOGQqtHF2UszTcpj6lHEAW7%2FfELEo5VXeqTdv%2Fw1%2BzlYjEcAQxTlqmqS1iWpHni%2FEKZc5Gmw5zkq2N5YlZP83bZSwCcPF3lXHODYkM6MrY5oxq%2B68Xa0M%2BaTFubVcoZnIwir1hDT9%2B1fFHCspwGxF017gIYvnrsXTod75DPUg5Z8DhWVZXOpMjZZe34zYdUCK%2Fp6%2B9qT1e%2B8n7VD4OAQmj36bWh7pNgF2SZsRTjEy7t2UhId%2BxP0WIgCRJt9zyjteJ0%2FW70QsLznl2Ql9Xb7KP7f%2BJ%2F1Fs2k1%2B023Not38

[wmertens]

So what's happening is that you're reading the computed signal in the setInterval callback, which runs outside of Qwik context, and it throws when you're reading it the first time.

I'm not sure if we can avoid this, but in any case, I don't understand why the deserialization didn't already import the qrl, it should do that for computeds

[wmertens]

found the issue: preloading QRLs is broken since I changed the serialization.

So this kind of error can still happen when it's fixed but more rarely.

[wmertens]

maybe we should just return a promise when the value is used outside the qwik context :-/

[thejackshelton]

fixed in 2.0 beta 13