Add asset close to amount field to transaction (algorand#1886)

This PR adds `AssetClosingAmount` to the `ApplyData`, conditioned by a new `ConsensusParam.EnableAssetCloseAmount`. A corresponding `AssetClosingAmount` was added to the REST API to align with the variable already presents on the indexer v2.

config/consensus.go

@@ -342,6 +342,10 @@ type ConsensusParams struct {
 	// CompactCertSecKQ is the security parameter (k+q) for the compact
 	// certificate scheme.
 	CompactCertSecKQ uint64
+
+	// EnableAssetCloseAmount adds an extra field to the ApplyData. The field contains the amount of the remaining
+	// asset that were sent to the close-to address.
+	EnableAssetCloseAmount bool
 }
 
 // ConsensusProtocols defines a set of supported protocol versions and their
@@ -827,6 +831,9 @@ func initConsensusProtocols() {
 	vFuture.CompactCertWeightThreshold = (1 << 32) * 30 / 100
 	vFuture.CompactCertSecKQ = 128
 
+	// Enable AssetCloseAmount field
+	vFuture.EnableAssetCloseAmount = true
+
 	Consensus[protocol.ConsensusFuture] = vFuture
 }
 

daemon/algod/api/algod.oas2.json

@@ -2148,6 +2148,10 @@
             "description": "Closing amount for the transaction.",
             "type": "integer"
           },
+          "asset-closing-amount": {
+            "description": "The number of the asset's unit that were transferred to the close-to address.",
+            "type": "integer"
+          },
           "confirmed-round": {
             "description": "The round where this transaction was confirmed, if present.",
             "type": "integer"

daemon/algod/api/algod.oas3.yml

@@ -463,6 +463,10 @@
                   "description": "The application index if the transaction was found and it created an application.",
                   "type": "integer"
                 },
+                "asset-closing-amount": {
+                  "description": "The number of the asset's unit that were transferred to the close-to address.",
+                  "type": "integer"
+                },
                 "asset-index": {
                   "description": "The asset index if the transaction was found and it created an asset.",
                   "type": "integer"
@@ -3129,6 +3133,10 @@
                       "description": "The application index if the transaction was found and it created an application.",
                       "type": "integer"
                     },
+                    "asset-closing-amount": {
+                      "description": "The number of the asset's unit that were transferred to the close-to address.",
+                      "type": "integer"
+                    },
                     "asset-index": {
                       "description": "The asset index if the transaction was found and it created an asset.",
                       "type": "integer"
@@ -3189,6 +3197,10 @@
                       "description": "The application index if the transaction was found and it created an application.",
                       "type": "integer"
                     },
+                    "asset-closing-amount": {
+                      "description": "The number of the asset's unit that were transferred to the close-to address.",
+                      "type": "integer"
+                    },
                     "asset-index": {
                       "description": "The asset index if the transaction was found and it created an asset.",
                       "type": "integer"

daemon/algod/api/server/v1/handlers/handlers.go

@@ -315,6 +315,10 @@ func assetTransferTxEncode(tx transactions.Transaction, ad transactions.ApplyDat
 		xfer.CloseTo = tx.AssetTransferTxnFields.AssetCloseTo.String()
 	}
 
+	if ad.AssetClosingAmount != 0 {
+		xfer.CloseToAmount = ad.AssetClosingAmount
+	}
+
 	return v1.Transaction{
 		AssetTransfer: &xfer,
 	}