Type casting errors when using a different CommitMultiStore implementation

[javiersuweijie]

Summary

Type cast in baseapp.Init() prevents usage of any other implementations of CommitMultiStore

cosmos-sdk/baseapp/baseapp.go

Lines 361 to 364 in 560ba86

	rms, ok := app.cms.(*rootmulti.Store)
	if !ok {
	return fmt.Errorf("invalid commit multi-store; expected %T, got: %T", &rootmulti.Store{}, app.cms)
	}

Problem Definition

I'm exploring to see how we can update mantlemint to support non-terra chains. Mantlemint uses a different implementation of the CommitMultiStore that is more space efficient and performant for queries.

Seems like the check is unnecessary since there is currently only a single implementation of CommitMultiStore and all of them should adhere to the GetPruning() interface.

Proposal

Remove the interface casting to allow other implementations of a CommitMultiStore.

[tac0turtle]

thanks for the opening this issue, want to submit a PR? @alexanderbez can help in review

[javiersuweijie]

thanks for the opening this issue, want to submit a PR? @alexanderbez can help in review

Submitted the PR. What are the chances that this will be cherry-picked into a 0.46.x release?