$inspect shows duplicate elements in arrays when using splice

[samausir]

Describe the bug

I have an array let arr = $state(['a', 'b', 'c']). When I arr.splice(1, 1), $inspect(arr) first shows me ['a', 'c', 'c'] before showing the correct version, which is ['a', 'c'].

This was raised in #13494 before and was fixed, but it apparently has made a comeback.

Reproduction

https://svelte.dev/playground/0955025b01db4aa99efcd441351b33e9?version=5.19.2

Logs

init 
(3) [ "a" ,"b" ,"c" ]
update 
(3) [ "a" ,"c" ,"c" ]
update 
(2) [ "a" ,"c" ]

System Info

N/A

Severity

annoyance

[paoloricciuti]

This is kinda of expected since it's how the browser "apply" slice...we could probably use the same trick Rich used in #15073 but i'd say let's wait to see if #15069 is merged first so that we can reuse that code.