Tron: Spend a prebuilt TriggerSmartContract call

[j0ntz]

CHANGELOG

Does this branch warrant an entry to the CHANGELOG?

• Yes
• No

Dependencies

none

Description

Asana: https://app.asana.com/0/1215088146871429/1216839790397157

TronEngine.makeSpend only read otherParams for the four staking actions. Everything
else fell through to makeTransferJson / encodeTRC20Transfer, so a DEX swap that
arrives as a finished TriggerSmartContract call was silently rewritten into a plain
transfer and never executed the swap.

What changed

• asTronContractCallOtherParams (tronTypes.ts) recognizes { contractJson, feeLimit?, note? }
  where contractJson is a TriggerSmartContract. Every level uses .withRest, so the payload
  reaches the transaction builder byte-identical to what the provider sent — parameter.type_url
  is load-bearing here, it is serialized into the signed raw data.
• makeContractCallTransaction builds the transaction through the existing
  txBuilder({ contractJson, feeLimit, note }) and returns otherParams unchanged, so signTx
  (getOtherParams → txBuilder → sign) needed no change. It refuses a payload whose
  owner_address is not this wallet.
• Amount accounting follows the transfer path: a token call reports the caller's amount with the
  fee as parentNetworkFee; a mainnet call reports the contract's own call_value plus the fee,
  since that is the TRX the chain actually moves.
• calcTxFee gained contractCallOpts. The existing energy estimate dry-runs a canonical
  transfer(address,uint256), which says nothing about a swap router, so a contract call is
  estimated from its own data and call_value. A failed dry run falls back to the existing
  default rather than blocking the spend, because a call that depends on an approval which has
  not been broadcast yet cannot be simulated. The existing token-transfer estimate is untouched.
• The CLI make-spend command takes --otherParams <json>, so the new path can be driven
  outside a swap plugin.

Testing

Unit tests (test/tron/tronContractCall.test.ts) use the real Rango payload from the task:
the cleaner accepts it, rejects staking and transfer payloads, and the built raw data matches
the provider's raw_data_hex and txID byte-for-byte.

Driven end to end on the iOS sim against edge-exchange-plugins#484:
a TRX → USDT swap through Rango reached the success scene, and on-chain
42fd4970…9650
is a TriggerSmartContract with contractRet: SUCCESS, call_value 39.148 TRX, selector
cef95229 against the Sun Swap router, and the same transaction delivered 13.004043 USDT.
Screenshots in a comment below.

---

Note

Medium Risk
Changes the Tron spend path for otherParams contract calls and fee math; guards reduce silent mis-sends, but wrong validation or accounting could still affect real swap spends and TRX balances.

Overview
Tron DEX swaps no longer get rewritten into plain TRX/TRC20 transfers when a swap plugin passes a finished TriggerSmartContract in otherParams. makeSpend now routes valid payloads through makeContractCallTransaction, which signs the provider’s contractJson byte-identical via the existing txBuilder path.

Fee estimation adds contractCallOpts to calcTxFee: energy is dry-run with /wallet/triggerconstantcontract using the call’s own data and call_value, with revert detection on ret and result.message, and a default fallback when simulation fails (e.g. pending approval). Malformed contract-call attempts are blocked by asTronContractCallIntent so they error instead of falling through to a transfer to the contract address.

The CLI make-spend command accepts --otherParams JSON for testing this path outside swap plugins.

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[j0ntz]

📸 Test evidence: Rango TRX → USDT swap on iOS sim

rango trx usdt quote

rango trx swap success

rango trx tx details

Captured by the agent's in-app test run (build-and-test).

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