Indicate list of OR signatories

Questions
9

Ok, if I now understood you correctly, this sort of thing can be implemented on the authorization side, but it’s currently tricky on the privacy/visibility side as changes to the group/role have to be propagated through to the (immutable) contracts that such changes affect.

Ignoring visibility issues, we could implement this:

template TradeApproverGroup
  with
     admins : Set Party
     members : Set Party
     groupName : Text
  where
     signatory admins
     observer members
     key (admins, groupName) : (Set Party, Text)
     maintainer key._1

     choice AddMember ...
     choice RemoveMember ...
     choice PromoteMember ...
     choice DemoteAdmin ...


template TradeApprovalRequest
  with
     group : TradeApproverGroup
     requester : Party
  where
     signatory requester
     observer group.members

     choice Accept : ContractId TradeApproval
     with
       approver : Party
     do
       (groupCid, actualGroup) <- fetchByKey @TradeApproverGroup (group.admins, group.name)
       assert (approver /= requester && group == actualGroup)
       create TradeApproval with ..

The problem in the above is: If the group gets updated whilst there is an outstanding TradeApprovalRequest, how do you update the group on the request?

A proposed solution is to allocate parties for such groups:

template TradeApproverGroup
  with
     admins : Set Party
     groupParty : Party
     members : Set Party
  where
     signatory admins, groupParty
     observer members
     key groupParty : Party
     maintainer key

     choice AddMember ...
     choice RemoveMember ...
     choice PromoteMember ...
     choice DemoteAdmin ...


template TradeApprovalRequest
  with
     group : Party
     requester : Party
  where
     signatory requester
     observer group

     choice Accept : ContractId TradeApproval
     with
       approver : Party
     do
       (groupCid, actualGroup) <- fetchByKey @TradeApproverGroup group
       assert (approver /= requester && approver `elem` actualGroup.members)
       create TradeApproval with ..

The feature that’s missing to make that work is for all members to be able to read as the group party over the API so that they can see the TradeApprovalRequest. Sadly, this is not possible yet so for now one has to keep the membership relatively stable, or propagate changes through to the observers.

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