add ValidatorData field to Message

[vyzo]

Useful for passing data from the validation to the application.

[whyrusleeping]

Thanks @vyzo !

[aschmahmann]

@vyzo where is this field set, did you forget to add a file?

[aschmahmann]

Also, is this just a convenience thing since the data is already available by emitting data from the validators?

[whyrusleeping]

Yes, this is for validators to set, and for subscribers to consume. Basically, I'd like to avoid having to unmarshal things twice

[vyzo]

it is initialized to nil when we construct the message; it's for use from validators, they can set it to pass data to the application (eg. the unmarshalled payload to avoid unmarshalling twice).
This is a filecoin ask.

[aschmahmann]

@vyzo Ok, no problem with convenience functions.

Although, I'd like to point out that in less than 30 minutes you've just passed a change that causes problems if there are multiple validators for a single message since they may both clobber the ValidateData field. There is also no documentation for this behavior.

[Stebalien]

This completely breaks the abstraction of pubsub as a shared service. There's no reason we can't have validators return additional data (along with an error) and have the validation subsystem collect all the extra validation data.

[fxfactorial]

So what's the proper usage of this field?

[vyzo]

It allows the validation to pass data to the application; one common usage (eg in lotus) is to pass the decoded message to avoid parsing and decoding twice.

[fxfactorial]

I get that and that’s my intent as well , just seems like there was an extended convo about it and wondering if any issues or assumptions need to be held when using it this way

[vyzo]

The issue in the convo was about multiple validators competing for the coveted field, but it's a very rare occurrence to have a message that validates in multiple topics.

non-issue.