feat(x/accounts): On-chain multisig (cosmos#19988)

x/accounts/CHANGELOG.md

@@ -23,4 +23,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 # Changelog
 
-## [Unreleased]
+## [Unreleased]
+
+### Features
+
+* [#19988](https://github.com/cosmos/cosmos-sdk/pull/19988) Implemented `x/accounts/multisig`.

x/accounts/accountstd/test_util.go

@@ -25,3 +25,7 @@ func NewMockContext(
 		ctx, ss, accNumber, accountAddr, sender, funds, moduleExec, moduleExecUntyped, moduleQuery,
 	), ss
 }
+
+func SetSender(ctx context.Context, sender []byte) context.Context {
+	return implementation.SetSender(ctx, sender)
+}

x/accounts/defaults/base/account.go

@@ -38,6 +38,7 @@ func NewAccount(name string, handlerMap *signing.HandlerMap) accountstd.AccountC
 			Sequence:        collections.NewSequence(deps.SchemaBuilder, SequencePrefix, "sequence"),
 			addrCodec:       deps.AddressCodec,
 			signingHandlers: handlerMap,
+			hs:              deps.Environment.HeaderService,
 		}, nil
 	}
 }

x/accounts/defaults/multisig/README.md

@@ -0,0 +1,153 @@
+# Multisig Accounts
+
+
+* [State](#state)
+  * [Config](#config)
+  * [Proposal](#proposal)
+  * [Members](#members)
+* [Methods](#methods)
+    * [MsgInit](#msginit)
+    * [MsgUpdateConfig](#msgupdateconfig)
+    * [MsgCreateProposal](#msgcreateproposal)
+    * [MsgVote](#msgvote)
+    * [MsgExecuteProposal](#msgexecuteproposal)
+
+The x/accounts/defaults/multisig module provides the implementation for multisig accounts within the x/accounts module.
+
+## State
+
+The multisig account keeps its members as a map of addresses and weights (`<[]byte, uint64>`), a config struct, a map of proposals and a map of votes.
+
+```go
+type Account struct {
+	Members  collections.Map[[]byte, uint64]
+	Sequence collections.Sequence
+	Config   collections.Item[v1.Config]
+
+	addrCodec     address.Codec
+	headerService header.Service
+	eventService  event.Service
+
+	Proposals collections.Map[uint64, v1.Proposal]
+	Votes     collections.Map[collections.Pair[uint64, []byte], int32] // key: proposalID + voter address
+}
+```
+
+### Config
+
+The config contains the basic rules defining how the multisig will work. All of these fields can be modified afterwards by calling [MsgUpdateConfig](#msgupdateconfig).
+
+```protobuf
+message Config {
+  int64 threshold = 1;
+
+  int64 quorum = 2;
+
+  // voting_period is the duration in seconds for the voting period.
+  int64 voting_period = 3;
+
+  // revote defines if members can change their vote.
+  bool revote = 4;
+
+  // early_execution defines if the multisig can be executed before the voting period ends.
+  bool early_execution = 5;
+}
+```
+
+### Proposal
+
+The proposal contains the title, summary, messages and the status of the proposal. The messages are stored as `google.protobuf.Any` to allow for any type of message to be stored.
+
+```protobuf
+message Proposal {
+  string   title                        = 1;
+  string   summary                      = 2;
+  repeated google.protobuf.Any messages = 3;
+
+  // if true, the proposal will execute as soon as the quorum is reached (last voter will execute).
+  bool execute = 4;
+
+  // voting_period_end will be set by the account when the proposal is created.
+  int64 voting_period_end = 5;
+
+  ProposalStatus status = 6;
+}
+```
+
+### Members
+
+Members are stored as a map of addresses and weights. The weight is used to determine the voting power of the member.
+
+
+## Methods
+
+### MsgInit
+
+The `MsgInit` message initializes a multisig account with the given members and config.
+
+```protobuf
+message MsgInit {
+  repeated Member members = 1;
+  Config          Config  = 2;
+}
+```
+
+### MsgUpdateConfig
+
+The `MsgUpdateConfig` message updates the config of the multisig account. Only the members that are changing are required, and if their weight is 0, they are removed. If the config is nil, then it will not be updated.
+
+```protobuf
+message MsgUpdateConfig {
+  // only the members that are changing are required, if their weight is 0, they are removed.
+  repeated Member update_members = 1;
+
+  // not all fields from Config can be changed
+  Config Config = 2;
+}
+```
+
+### MsgCreateProposal
+
+Only a member can create a proposal. The proposal will be stored in the account and the members will be able to vote on it.
+
+If a voting period is not set, the proposal will be created using the voting period from the config. If the proposal has a voting period, it will be used instead.
+
+```protobuf
+message MsgCreateProposal {
+  Proposal proposal = 1;
+}
+```
+
+### MsgVote
+
+The `MsgVote` message allows a member to vote on a proposal. The vote can be either `Yes`, `No` or `Abstain`.
+
+```protobuf
+message MsgVote {
+  uint64 proposal_id = 1;
+  VoteOption   vote        = 2;
+}
+
+// VoteOption enumerates the valid vote options for a given proposal.
+enum VoteOption {
+  // VOTE_OPTION_UNSPECIFIED defines a no-op vote option.
+  VOTE_OPTION_UNSPECIFIED = 0;
+  // VOTE_OPTION_YES defines the yes proposal vote option.
+  VOTE_OPTION_YES = 1;
+  // VOTE_OPTION_ABSTAIN defines the abstain proposal vote option.
+  VOTE_OPTION_ABSTAIN = 2;
+  // VOTE_OPTION_NO defines the no proposal vote option.
+  VOTE_OPTION_NO = 3;
+}
+```
+
+
+### MsgExecuteProposal
+
+The `MsgExecuteProposal` message allows a member to execute a proposal. The proposal must have reached the quorum and the voting period must have ended.
+
+```protobuf
+message MsgExecuteProposal {
+  uint64 proposal_id = 1;
+}
+```