State tracing in runtime

[gnunicorn]

Especially for balance transfers exchanges are asking us to provide not only the wasm blob and the final state but what is called "state traces", effectively the specific low level functions that are being executed by a specific transaction and the state changes those finally lead to. In past implementations we just added logging facilities to the specific function calls and be done with it but with the separation of concerns in substrate between client and runtime this is a bit more tricky for us.

Following #6916, we need to add event_debug!-traces with the to-be-hashed-key and its value prior to any unhashed-call that changes state – maybe also add event_trace! to the inner of unhashed as well as to all non-mutating-unhashed-calls to allow for debugging. Combined with the span-tree we should be able to identify which extrinsic lead to which changes.

[bkchr]

Isn't this issue basically this: #6401 + state=tracing?

[bkchr]

And how should non decl_storage storage accesses being traced?

[bkchr]

Maybe we could just support a node only changes trie?

[xlc]

Sounds like #4939?

RPC state_queryStorage is already able to fetch all the changes of a particular storage key and all the blocks causing the changes.

[shawntabrizi]

@gnunicorn @dvdplm Can we close this?

[stale]

Hey, is anyone still working on this? Due to the inactivity this issue has been automatically marked as stale. It will be closed if no further activity occurs. Thank you for your contributions.