really skip label check by ignoring incoming labels

[replay]

currently the flag SkipInboundLabelCheck doesn't really make memberlist skip the label check, because if this flag is enabled and the memberlist client is configured with no label and then it receives a message that has a label then prints a warning and drops the received message. I think if SkipInboundLabelCheck is enabled then it shouldn't matter whether incoming messages have a label, at all.

[56quarters]

Am I correct that this change is only required during the migration of a cluster that doesn't use to labels to start using them? If so should we plan to upstream this at all or just add it to our fork temporarily? I suppose this is useful for more than just Mimir so perhaps upstreaming makes sense.

[replay]

Am I correct that this change is only required during the migration of a cluster that doesn't use to labels to start using them?

Correct

If so should we plan to upstream this at all or just add it to our fork temporarily? I suppose this is useful for more than just Mimir so perhaps upstreaming makes sense.

I think upstreaming it makes sense, because as you said it could be useful to more people. I want to test it first in a real-world scenario before upstreaming though

[pracucci]

I checked the original PR hashicorp#246 to see if there was any discussion about SkipInboundLabelCheck, cause it looks weird the way it was implemented. I'm wondering if it's us missing something.

[pracucci]

I keep not understanding why it was implemented that way in the original PR, but after double checking the code I think this change is good.

[slim-bean]

I keep not understanding why it was implemented that way in the original PR, but after double checking the code I think this change is good.

I also looked at the initial PR and I'm not sure why it was implemented the way it is, I suspect it was an oversight because the way it's implemented in main doesn't seem like it really serves any useful purpose:

If the flag is true: any packet with a label will fail
If the flag is false: any packet with a label will fail

¯\_(ツ)_/¯

[pracucci]

4 people looking at it, and looks good, so let's merge it.