[Svelte5] Very strange behavior with a $state() created by a $state.snapshot()

[fsoft72]

Describe the bug

It seems that $state()s created by copying a $state.snapshot() behave differently.
I have created a small example that does the following:

1. Create a small $state() called user
2. Pass the user to a component
3. The component creates a new $state() by cloning data in this way: $state($state.snapshot(_user))
4. The new user object is passed to some <input> types with the bind:value directive
5. When the save button is pressed, the old values are returned to the onsave callback ... unless you spread the object.

So, in short:

• onsave(user) will return the OLD values, even if they are saved inside the new user object
• onsave({...user}) will return the correct values

Tested against: svelte 5.0.0-next.243

Reproduction

I have created a small REPL Here

Logs

No response

System Info

System:
    OS: Linux 6.8 Ubuntu 24.04 LTS 24.04 LTS (Noble Numbat)
    CPU: (24) x64 AMD Ryzen 9 7900X 12-Core Processor
    Memory: 53.73 GB / 62.01 GB
    Container: Yes
    Shell: 5.2.21 - /bin/bash
  Binaries:
    Node: 20.11.1 - ~/.nvm/versions/node/v20.11.1/bin/node
    Yarn: 1.22.19 - ~/.yarn/bin/yarn
    npm: 10.2.4 - ~/.nvm/versions/node/v20.11.1/bin/npm
    pnpm: 9.9.0 - ~/.local/share/pnpm/pnpm
    bun: 1.0.0 - ~/.bun/bin/bun
  Browsers:
    Brave Browser: 127.1.68.137
    Chrome: 127.0.6533.88

### Severity

blocking all usage of svelte

[7nik]

Isn't it just misleading info in the console and what #13070 tries to fix?

[fsoft72]

Isn't it just misleading info in the console and what #13070 tries to fix?

I think you are right, because this new REPL always work