[BUG] CLUSTER SLOTS crashes when used with fake-client.

[allenss-amazon]

Describe the bug

If a module creates a fake client and executes a VM_CALL to "CLUSTER SLOTS", then it crashes the server. Some debugging appeared to indicate that this was because CLUSTER SLOTS creates it's own fake client in order to cache its results for better performance. This doesn't work when the original client was also fake.

To reproduce

Have a module create a fake context and then perform an VM_Call to "CLUSTER SLOTS" command.

Expected behavior

No crash and good results from CLUSTER SLOTS

[bandalgomsu]

If no one is working on it, could I contribute? 😄

[zuiderkwast]

@bandalgomsu Yes, do you already know how to fix it and you think you can finish it very quickly like today or Monday? Then we can include it in 9.0.1. I already prepare for the 9.0.1 release.

I was thinking I can take a look today too.

[zuiderkwast]

@allenss-amazon It would help if you could share the debugging you've done.

What is a "fake context" and how do you create it? Do you mean a thread-safe context?

Can you attach part of the crash report, such as the stack trace?

[bandalgomsu]

I Create PR ! #2915 😄

[allenss-amazon]

Yes, a thread-safe context is what I meant. Sorry I don't have a backtrace handy.