SPEC: XAnchor Gov. System Edge Cases

[lazovicff]

Overview

In XAnchor, there is a lot of Edge cases in the gov. system, I will try to cover most of them here so we can keep track or address them by writing first a failing test and then later on fix it.

For all of the following tasks/checks we are going to refer to Chain A as the source chain and Chain B as the target chain.

Checklist

• Calling propose_to_link_anchor to create on-chain proposal on chain A could fail to link anchors if the proposal not passed.
• After the proposal passed on chain A, the send_link_anchor_message gets called we send two messages:
  • save_link_proposal as a sibling parachain, which just puts the link proposal in the pending link, what would happen if the target tree on the target chain is already linked to something else?
  • handle_link_anchor_message as a sovereign account, to actually kick the proposal on the other chain, what if it get called by normal Signed account?
  • handle_link_anchor_message as a sovereign account, to actually kick the proposal on the other chain, what if the parachain sovereign account does not have the value as balance?
• On chain B what happens if the proposal didn't pass? How the chain A could know about that? to remove that anchor from the PendingLinkedAnchors list?