Throw on hydration mismatch

[maximedupre]

Describe the problem

Hydration mismatch is pretty important error, but right now it's only a warning.

The problem is that this error isn't easily captured in Sentry, which makes it hard to debug in prod.

Describe the proposed solution

Throw on hydration mismatch.

or

Add a config where we can allow it to throw.

Importance

would make my life easier

[dummdidumm]

Some clarifying questions:

• Are you calling hydrate from Svelte directly or are you using it indirectly via SvelteKit?
• By "throwing" do you mean "the UI should not load"? (right now we reinitialize via mount as a fallback by default)

If the answer to 1 is "directly" and 2 is "don't recover", then you can do this today (hydrate({ recover: false, ... }))

[maximedupre]

Some clarifying questions:

• Are you calling hydrate from Svelte directly or are you using it indirectly via SvelteKit?
• By "throwing" do you mean "the UI should not load"? (right now we reinitialize via mount as a fallback by default)

If the answer to 1 is "directly" and 2 is "don't recover", then you can do this today (hydrate({ recover: false, ... }))

Thanks for the response!

• I'm using it indirectly via SvelteKit.
• Not necessarily. It could still load and use the fallback. Maybe an async throw that doesn't break any current mechanism, so long as Sentry captures it

[dummdidumm]

yeah it would have to be an async throw in that case, no other way to have it not break other stuff