@benmccann any ideas ?

can you share a minimal reproduction of this error please and show how this information would be useful to the user receiving these logs and what exactly would be logged?

What happens if there are multiple errors. logging all of them in full can cause a lot of extra output, so it might be better to set a breakpoint and observe the error when it is happening.

I don't have a reproducible example for now but for example

I have first the error

Then if I reload the page I got

Which is not helpful

here is a Minimal example

https://stackblitz.com/edit/withastro-astro-j41nfv

Note that if you add

    "svelte": "^5.0.0-next.1"

to the package .json it's working normally

svelte5 does not use svelte-hmr, so no surprise there.

the example you shared has a lot of astro files that are not relevant, I see a Test.svelte component that has an obvious error (ee is not defined but used in the template). Are you saying that this is not communicated to you at all in your ide or browser?
cc @bluwy

Thanks for the info on svelte5

The example show that with a svelte component, if there are errors (even an "obvious" one like ee is not defined, we don't have clear instructions.

We just have

[HMR][Svelte] Unrecoverable HMR error in <Test>: next update will trigger a full reload

Or sometimes (in a personal project for example) :

• the page crash
• the error is displayed
• but if I reload the page, it crashes again but with [HMR][Svelte] Unrecoverable HMR error in <Test>: next update will trigger a full reload with only error

i was unable to see the error messages you mentioned in the stackblitz that has been provided.

Going from the astro svelte example, I saw the appropriate error popup when commenting count in Counter.svelte.

https://stackblitz.com/edit/github-asymdn?file=src%2Fcomponents%2FCounter.svelte,src%2Fpages%2Findex.astro

The difference to your example is that Counter is added with the astro directive client:visible. In your example you use client:only (which should be client:only="svelte") and in that case it does not show the error. I don't know what astro client:only does but i suggest you raise it with them.

Whatever is happening, the error of svelte-hmr won't help the user diagnose the problem in their code. If at all it would be helpful to show them the filename / component name that caused it. But the stacktrace is completely outside of the users code or reach.

Okay thanks for the analysis

Here is the issue withastro/astro#9158