`tx hash` fails on fee-bump transactions

[leighmcculloch]

What version are you using?

stellar-cli 28.1.0 (d0b26d9, built from main).

What did you do?

I wrapped a transaction in a fee bump and asked for its hash:

stellar tx new payment --source alice --destination bob --amount 1 \
  --network testnet --build-only > tx.b64

stellar tx hash --network testnet < tx.b64

stellar tx decode < tx.b64 \
  | jq -c --arg fs "$(stellar keys address bob)" \
      '{tx_fee_bump:{tx:{fee_source:$fs,fee:10000,inner_tx:{tx:.tx},ext:"v0"},signatures:[]}}' \
  | stellar tx encode \
  | stellar tx hash --network testnet

What did you expect to see?

The fee-bump transaction's hash.

What did you see instead?

The plain transaction hashes fine, but the fee-bump envelope is rejected:

❌ error: only transaction v1 is supported
(exit status 1)