Error compiling component when <option> without value attribute contains <slot />

[trbrc]

A component with an <option> tag that has no value attribute and contains another tag, such as <slot />, will refuse to compile with a vague error:

/* Error compiling component

undefined is not an object (evaluating 'this.node.start')

*/

Reproduction: https://svelte.dev/repl/676c6c2d7a8a4684a261935c488b763a?version=3.20.1

Changing it to <option value><slot/></option> is enough to make it work.

[EmilTholin]

You are on a roll @trbrc. Thank you so much! It's very much appreciated!

It seems that an Expression is created with info set to undefined, so when start is accessed on this.node the error is thrown. Very interesting.

[EmilTholin]

Svelte can't currently handle anything other than pure text as option content if no value attribute is given. E.g. a p element instead of a slot throws the same error.

I'm not sure how far we want to go with this. Possibly walk the option content and concatenate all the text (like the browser does), and take the slot content if it's a slot?

[trbrc]

@Conduitry I just saw the request for clarification. What kind of clarification are you looking for?

I realize this is not a high priority bug, as it's a corner case with low real world impact, but I would suggest it's a bug rather than request for enhancement. Getting a vague compiler error in this scenario can't be the correct behavior, and it's not obvious that adding the value attribute would fix it.

[antony]

Changing to bug as I can see that this isn't the correct behaviour given the REPL. What the correct behaviour (gracefully just render, or add a dev warning) is though, I don't know.

[Rich-Harris]

This works in Svelte 5