Merge branch 'master' into ryan/fix-init-chain-id

CHANGELOG.md

@@ -88,6 +88,11 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (server) [#9704](https://github.com/cosmos/cosmos-sdk/pull/9704) Start GRPCWebServer in goroutine, avoid blocking other services from starting.
 * [\#9762](https://github.com/cosmos/cosmos-sdk/pull/9762) The init command uses the chain-id from the client config if --chain-id is not provided
 
+### State Machine Breaking
+
+* (x/bank) [\#9611](https://github.com/cosmos/cosmos-sdk/pull/9611) Introduce a new index to act as a reverse index between a denomination and address allowing to query for
+  token holders of a specific denomination. `DenomOwners` is updated to use the new reverse index.
+
 ## [v0.43.0-rc0](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.43.0-rc0) - 2021-06-25
 
 ### Features

container/option_test.go

@@ -0,0 +1 @@
+package container_test

docs/architecture/adr-043-nft-module.md

@@ -281,6 +281,15 @@ message QueryClassesResponse {
 }
 ```
 
+
+### Interoperability
+
+Interoperability is all about reusing assets between modules and chains. The former one is achieved by ADR-33: Protobuf client - server communication. At the time of writing ADR-33 is not finalized. The latter is achieved by IBC. Here we will focus on the IBC side.
+IBC is implemented per module. Here, we aligned that NFTs will be recorded and managed in the x/nft. This requires creation of a new IBC standard and implementation of it.
+
+For IBC interoperability, NFT custom modules MUST use the NFT object type understood by the IBC client. So, for x/nft interoperability, custom NFT implementations (example: x/cryptokitty) should use the canonical x/nft module and proxy all NFT balance keeping functionality to x/nft or else re-implement all functionality using the NFT object type understood by the IBC client. In other words: x/nft becomes the standard NFT registry for all Cosmos NFTs (example: x/cryptokitty will register a kitty NFT in x/nft and use x/nft for book keeping). This was [discussed](https://github.com/cosmos/cosmos-sdk/discussions/9065#discussioncomment-873206) in the context of using x/bank as a general asset balance book. Not using x/nft will require implementing another module for IBC.
+
+
 ## Consequences
 
 ### Backward Compatibility
@@ -299,6 +308,7 @@ This specification conforms to the ERC-721 smart contract specification for NFT
 
 ### Negative
 
++ New IBC app is required for x/nft
 
 ### Neutral
 

simapp/app_test.go

@@ -123,8 +123,13 @@ func TestRunMigrations(t *testing.T) {
 			false, "", true, "no migrations found for module bank: not found", 0,
 		},
 		{
-			"can register and run migration handler for x/bank",
+			"can register 1->2 migration handler for x/bank, cannot run migration",
 			"bank", 1,
+			false, "", true, "no migration found for module bank from version 2 to version 3: not found", 0,
+		},
+		{
+			"can register 2->3 migration handler for x/bank, can run migration",
+			"bank", 2,
 			false, "", false, "", 1,
 		},
 		{