[Bug]: Index out of range exception on transform multiple subscribes

[LouisSimon73]

Describe the bug 🐞

When we store tranformed changeSet stream in variable and subscribe multiple time on this variable, on exception occures on the second subscription.

• We did not have the problem in 7.4.3;
• It does not happen with connectable observable ([variable].Publish().RefCount()).

Thank you in advance !

Step to reproduce

var l_sourceList = new SourceList<int>();

l_sourceList.AddRange(new[] { 0, 1, 2 });

var l_observable = l_sourceList.Connect()
    .Transform(o => o);

l_observable.Transform(o => o).Subscribe();
l_observable.Transform(o => o).Subscribe();

Reproduction repository

https://github.com/reactivemarbles/DynamicData

Expected behavior

This should happen...

Screenshots 🖼️

No response

IDE

Rider Windows

Operating system

Windows 10 Entreprise

Version

20H2 (19042.1645)

Device

PC

DynamicData Version

7.9.5

Additional information ℹ️

No response

[RolandPheasant]

I had the same issue a while back with Cache.Transform and thought I'd fixed it here too, so thanks for pointing this out.

Interestingly, your observation that .Publish().RefCount() fixes it is what I would always recommend with any shared state as it's much more efficient.

[LouisSimon73]

Thanks a lot for your quick fix !

[oysteinkrog]

@RolandPheasant We are seeing a very similar bug in TransformAsync, I will create an issue

[github-actions]

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