fix(app): reconciliation saveUnbalancedBlockHeight store-key mismatch (MOCA-670)

saveUnbalancedBlockHeight resolved the reconciliation commit store with a
freshly built storetypes.NewKVStoreKey, but rootmulti keys its store map by
StoreKey identity (rs.stores[key]). The fresh key is absent, so GetCommitStore
returns nil and the (*iavl.Store) assertion panics:
"interface conversion: types.CommitStore is nil, not *iavl.Store".

getUnbalancedBlockHeight already uses the mounted app.GetKey; align save with
it (and drop the now-unused storetypes import).

The panic is masked when inter-block-cache is enabled (the default): the
cache's Unwrap resolves by name and returns the underlying store. It only bites
nodes with inter-block-cache=false, where a reconciliation imbalance then halts
consensus with the opaque panic instead of the intended graceful
"unbalanced state at block height N, please use hardfork to bypass it".

Reproduced on the test-box: unit test (no cache) + single-node and 4-node
localnets with inter-block-cache=false. Adds a regression test that panics
before the fix and round-trips after.

Signed-off-by: puneetmahajan <59960662+puneet2019@users.noreply.github.com>

Author: puneet2019

app/reconciliation.go

@@ -8,7 +8,6 @@ import (
 
 	"cosmossdk.io/math"
 	"cosmossdk.io/store/iavl"
-	storetypes "cosmossdk.io/store/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 
@@ -160,7 +159,7 @@ func (app *Moca) reconPaymentChanges(ctx sdk.Context, paymentIavl *iavl.Store) b
 }
 
 func (app *Moca) saveUnbalancedBlockHeight(ctx sdk.Context) {
-	reconStore := app.CommitMultiStore().GetCommitStore(storetypes.NewKVStoreKey(reconStoreKey)).(*iavl.Store)
+	reconStore := app.CommitMultiStore().GetCommitStore(app.GetKey(reconStoreKey)).(*iavl.Store)
 	bz := make([]byte, 8)
 	binary.BigEndian.PutUint64(bz, uint64(ctx.BlockHeight()))
 	reconStore.Set(unbalancedBlockHeightKey, bz)

app/reconciliation_test.go

@@ -25,3 +25,22 @@ func TestParseDenomFromSupplyKey(t *testing.T) {
 	key, _ := hex.DecodeString("00616d6f6361")
 	require.Equal(t, "amoca", parseDenomFromSupplyKey(key))
 }
+
+// TestSaveUnbalancedBlockHeight_UsesMountedStoreKey is the regression test for MOCA-670.
+// saveUnbalancedBlockHeight resolved the reconciliation commit store with a freshly built
+// storetypes.NewKVStoreKey(reconStoreKey). rootmulti keys its store map by StoreKey identity
+// (rs.stores[key]), so a fresh key is absent -> GetCommitStore returns nil -> the (*iavl.Store)
+// assertion panics ("interface conversion: types.CommitStore is nil, not *iavl.Store").
+// getUnbalancedBlockHeight already uses the mounted app.GetKey and works; this asserts save
+// resolves + round-trips the same way. It panics (fails) on the unfixed code.
+func TestSaveUnbalancedBlockHeight_UsesMountedStoreKey(t *testing.T) {
+	mocaApp := EthSetup(false, nil)
+	ctx := mocaApp.NewContext(false).WithBlockHeight(4242)
+
+	require.NotPanics(t, func() { mocaApp.saveUnbalancedBlockHeight(ctx) },
+		"saveUnbalancedBlockHeight must resolve the recon store via the mounted key (app.GetKey)")
+
+	h, ok := mocaApp.getUnbalancedBlockHeight(ctx)
+	require.True(t, ok, "unbalanced height must be persisted")
+	require.Equal(t, uint64(4242), h)
+}