SvelteDate reactivity issue

[felix-roehrich]

Describe the bug

In a previous issue #12717, I discovered a caching problem which was fixed in 210. Now after updating I am having a similar issue. After some trials, this seems to have been introduced from 246 to 247 and exists in the latest 262.

Reproduction

1. Open the REPL and click the button. The text in the button should become unresponsive after a few clicks.
2. The issues disappears when the {date.getMonth() == 1} expression is moved away from the class:, e.g. having the expression as text will not trigger the issue.
3. Having just {date} as the button text is always unresponsive (This is minor caveat I discovered when trying to reproduce the issue.)

Logs

-

System Info

REPL

Severity

blocking an upgrade

[felix-roehrich]

Most likely #13171 is the culprit.

[paoloricciuti]

Most likely #13171 is the culprit.

I don't think that's the issue...i'm checking and it seems like it's setting the value to the same time. I'm investingating what's this all about

[paoloricciuti]

The problem is not with the class: part but generally with the fact that is accessed twice

REPL

[felix-roehrich]

Interesting, but in class directive it is only accessed once(?).

[paoloricciuti]

Interesting, but in class directive it is only accessed once(?).

Yeah there's definitely something else going on but i don't think it's related to that change. I'm investigating tho.

[paoloricciuti]

Mmm ok the problem with my repl is kinda the same as the class: one...those calls are treated as deriveds and that's why it doesn't work. So the problem was indeed introduced in that PR but it's not in the PR itself...it just surfaced the problem.

[paoloricciuti]

I think i need to surrender to this one and invoke @trueadm ...from my exploration the problem seems to be that the derived returned from getMonth() is marked as destroyed after the second click and that seems to be is what is causing the issue. I will try to continuing exploring what is destroying the derived but it's getting tangled 😄

[paoloricciuti]

This is a simpler (?) reproduction

The intermediate derived is probably destroying the children whilst being updated.