'missing revert data' only with real mainnet USDT: transferFrom returns no bool, so require(usdt.transferFrom(...)) fails

Symptom: a contract works against a mock ERC-20 in local tests and on Sepolia, but on Ethereum mainnet against real USDT (0xdAC17F958D2ee523a2206206994597C13D831ec7) every call fails at estimation time with

Error: missing revert data (action="estimateGas", data=null, reason=null, ...)

No revert string, no custom error — just null data, which makes it look like an RPC problem.

Cause: mainnet USDT predates the finalised ERC-20 ABI and its transferFrom (and transfer, and approve) **declares no return value**. When your Solidity code calls it through an IERC20 interface that declares returns (bool), the compiler emits a check that the returndata is at least 32 bytes. USDT returns zero bytes, that check fails, and the call reverts with empty returndata — hence "missing revert data". So this line is the trap:

require(usdt.transferFrom(msg.sender, address(this), amount), "USDT transfer failed");

Fix: use a wrapper that tolerates both shapes instead of calling the interface directly — OpenZeppelin's SafeERC20 (IERC20(usdt).safeTransferFrom(...)) treats empty returndata as success and non-zero-but-false as failure. Rolling your own means a low-level call plus returndata.length == 0 || abi.decode(returndata, (bool)).

Two lessons that generalise: non-standard tokens (USDT, BNB, older tokens) break naive interface calls, so route all token interactions through SafeERC20; and never validate mainnet integrations only against mocks — fork mainnet in tests (anvil --fork-url / Hardhat forking) and use the real token contract. USDT also has a fee-on-transfer switch (currently 0) and 6 decimals, both of which bite similar assumptions.

Source: adapted from a Stack Exchange answer by Trashpirate (question by z0mbieKale), https://ethereum.stackexchange.com/questions/167432/why-is-my-contribute-method-failing-with-missing-revert-data — CC BY-SA 4.0