Reactivity is broken when deriving .current on fromStore and updating the store asynchronously

[lassebomh]

Describe the bug

I can't describe the bug any more detailed that the title, but I've reduced it to a very small REPL. See repro

Reproduction

Here is the REPL, running the latest version (as of writing this) https://svelte.dev/playground/b878ade565124e529aa8c3e73275f564?version=5.35.2

It looks like it was introduced from 5.19.5 and onwards:

REPL for 5.19.4 works
REPL for 5.19.5 doesn't work

Seems to originate from: #15137

Annoyingly, the issue disappears if you try to $inspect the misbehaving variable.

Logs

System Info

System:
    OS: Linux 6.6 Ubuntu 24.04.1 LTS 24.04.1 LTS (Noble Numbat)
    CPU: (16) x64 AMD Ryzen 9 6900HS with Radeon Graphics
    Memory: 10.53 GB / 15.25 GB
    Container: Yes
    Shell: 5.2.21 - /bin/bash
  Binaries:
    Node: 22.13.1 - ~/.local/share/node/bin/node
    npm: 10.9.2 - ~/.local/share/node/bin/npm
    pnpm: 9.15.4 - ~/.local/share/node/bin/pnpm

Severity

annoyance

[paoloricciuti]

I was exploring this and I think the issue is with createSubscriber but I'm not entirely sure how to fix this...here's a different reproduction that doesn't use fromStore and still has the problem.

As i've explained the issue is that the derived is never updated since the version of createSubscriber is not updated because when it's not shown there's no subscriber to it. However this means that when check_dirtiness runs the wv of the derived is bigger than the version of createSubscriber so the derived it's considered CLEAN

[PatrickG]

Is this a duplicate of #15888?

[paoloricciuti]

Is this a duplicate of #15888?

It is...mmm, now I'm thorned if we should keep this open so that it's higher up or close this and move the context there (but then we need to remember to work on it)