audio: muted property not updating without bind:muted

[f1nzer]

Describe the bug

Setting muted={muted} on <audio> in Svelte 5.20 does not update the property when muted changes, but bind:muted={muted} works as expected. But it worked in Svelte 4.

Expected behavior: clicking the button should toggle the muted property on the audio as it did in Svelte 4
Actual behavior: muted does not update unless using bind:muted={muted}

Reproduction

Svelte 5.20 playground

Svelte 4.2.19 playground

Logs

System Info

System:
    OS: macOS 15.2
    CPU: (8) arm64 Apple M1 Pro
    Memory: 241.31 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 23.3.0 - /opt/homebrew/bin/node
    npm: 10.9.0 - /opt/homebrew/bin/npm
    pnpm: 10.3.0 - ~/Library/pnpm/pnpm
    bun: 1.1.21 - ~/.bun/bin/bun
  Browsers:
    Safari: 18.2

Chrome Version 132.0.6834.160 (Official Build) (arm64)

Severity

annoyance

[adiguba]

Hello,

I think it's come from #13751 and theses lines :

svelte/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js

Lines 544 to 548 in 21dadfc

	// Special case for Firefox who needs it set as a property in order to work
	if (name === 'muted') {
	state.init.push(b.stmt(b.assignment('=', b.member(node_id, b.id('muted')), value)));
	return false;
	}

The code is added on the "init" state of the component, but since the variable is reactive, this should be done on the "update" state.
Strangely, if I delete these lines it seems to work fine...

[paoloricciuti]

Hello,

I think it's come from #13751 and theses lines :

svelte/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js

Lines 544 to 548 in 21dadfc

// Special case for Firefox who needs it set as a property in order to work
if (name === 'muted') {
state.init.push(b.stmt(b.assignment('=', b.member(node_id, b.id('muted')), value)));
return false;
}
The code is added on the "init" state of the component, but since the variable is reactive, this should be done on the "update" state. Strangely, if I delete these lines it seems to work fine...

Just stumbled across this while fixing the $0 bug...did you also test in Firefox?

[adiguba]

I always use Firefox...

[paoloricciuti]

I always use Firefox...

Mmm...weird...just for the sake of honoring the comment i'm gonna fix it while keep assigning to the property but definitely worth exploring if it's dead code