Merge pull request #469 from oasisprotocol/mitjat/evm-expose-is-trans…

…fer-heuristic

/{runtime}/transactions: Add heuristic field for "is tx a native token transfer?"

api/spec/v1.yaml

@@ -2303,6 +2303,16 @@ components:
           type: object
           description: The method call body. May be null if the transaction was malformed.
           example: {"address": "t1mAPucIdVnrYBpJOcLV2nZoOFo=", "data": RBo+cAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=", "value": ""}
+        is_likely_native_token_transfer:
+          type: boolean
+          description: |
+            Whether this transaction likely represents a native token transfer.
+            This is based on a heuristic, and can change at any time without warning and possibly without updating the documentation.
+            The current heuristic sets this to `true` for:
+             - Transactions with method "accounts.Transfer". Those are always native token transfers.
+             - Transactions with method "evm.Call" that have no `data` field in their `body`. Those tend to be transfers, but the runtimes provides no reliable visibility into whether a transfer happened.
+            Note: Other transactions with method "evm.Call", and possibly "evm.Create", may also be (or include) native token transfers. The heuristic will be `false` for those.
+          example: true
         to:
           <<: *AddressType
           description: |

storage/client/client.go

@@ -1233,16 +1233,30 @@ func (c *StorageClient) RuntimeTransactions(ctx context.Context, p apiTypes.GetR
 			encryptionEnvelope.Format = *encryptionEnvelopeFormat
 			t.EncryptionEnvelope = &encryptionEnvelope
 		}
-		// TODO: Here we render Ethereum-compatible address preimages. That's
-		// a little odd to do in the database layer. Move this farther out if
-		// we have the energy.
+
+		// Render Ethereum-compatible address preimages.
+		// TODO: That's a little odd to do in the database layer. Move this farther
+		// out if we have the energy.
 		if sender0PreimageContextIdentifier != nil && sender0PreimageContextVersion != nil {
 			t.Sender0Eth = EthChecksumAddrFromPreimage(*sender0PreimageContextIdentifier, *sender0PreimageContextVersion, sender0PreimageData)
 		}
 		if toPreimageContextIdentifier != nil && toPreimageContextVersion != nil {
 			t.ToEth = EthChecksumAddrFromPreimage(*toPreimageContextIdentifier, *toPreimageContextVersion, toPreimageData)
 		}
 
+		// Heuristically decide if this is a native runtime token transfer.
+		// TODO: Similarly to above, this application logic doesn't belong here (= the DB layer);
+		// move it out if we establish a separate app/logic layer.
+		if t.Method != nil {
+			if *t.Method == "accounts.Transfer" {
+				t.IsLikelyNativeTokenTransfer = common.Ptr(true)
+			} else if *t.Method == "evm.Call" && t.Body != nil && (*t.Body)["data"] == "" {
+				// Note: This demands that the body.data key does exist (as we expect from evm.Call tx bodies),
+				// but has an empty value.
+				t.IsLikelyNativeTokenTransfer = common.Ptr(true)
+			}
+		}
+
 		ts.Transactions = append(ts.Transactions, t)
 	}
 

tests/e2e_regression/expected/emerald_txs.body

@@ -2011,6 +2011,7 @@
       "gas_used": 22142,
       "hash": "34204265b53f41a253f30651882bf1317739ac694ccfb966d2b57e54a82c8ee2",
       "index": 3,
+      "is_likely_native_token_transfer": true,
       "method": "evm.Call",
       "nonce_0": 60,
       "round": 1003586,