[bug] Investigate Performance issues with Svelte 5.5.2

[simeydotme]

Describe the bug

#157
^ from this issue

Link To Reproduce

• 5.1.0 is fine and works as expected
• but 5.9.0 has major performance issues with thousands of console.warn

[simeydotme]

If anyone has any insight, welcome to share it please 🙏

[simeydotme]

update;
pin-point the versions to 5.5.2 where the bug is introduced;

• 5.5.0 is fine
• 5.5.2 has the performance problem

Which is strange, as the PR for this ; sveltejs/svelte#14525 seems rather innocuous and only related to Date objects :/

https://github.com/sveltejs/svelte/releases/tag/svelte%405.5.2

[simeydotme]

just saw this;
sveltejs/svelte#14651 -> sveltejs/svelte#14643 which seems to be a very similar situation (warnings causing infinite loop)

[simeydotme]

OK, looks like Svelte have fixed the problem in 5.11.2;

So please either use Svelte < 5.5.0 or > 5.11.2 to avoid this performance damage!

sveltejs/svelte#14663
I had correctly assumed that we were not the only ones experiencing this, and they have quickly resolved it!
I will see if I can refactor a little after my vacation.

Thanks for your patience!

---

I will leave this open for a while so anyone who has a problem can see the resolution.
(who the heck am I kidding? Nobody ever reads prior-issues before opening 👀 )

[meodai]

I am running 5.14.3 and the range range with bind is super slow.

[simeydotme]

Oh boy. 🫠

I'm currently on vacation until Jan 20th, if anyone else figures out any issues with 5.14.3

Sadly the v5 launch has been quite turbulent

[simeydotme]

I am running 5.14.3 and the range range with bind is super slow.

@meodai I can't replicate.

can you please produce a reduced test case for me.

[meodai]

sorry I am traveling until the end of february, will when I am back!