Signature only flag bug on tx sign command

[antstalepresh]

Summary of Bug

When add signature only flag on transaction sign, it does not print any signature but just returns empty array.

{"signatures":[]}

Version

latest cosmos sdk master (55d7d0c)

Steps to Reproduce

Start daemon using below script.

#!/bin/bash

rm -rf $HOME/.simd/

cd $HOME

simd init --chain-id=testing testing --home=$HOME/.simd
simd keys add validator --keyring-backend=test --home=$HOME/.simd
simd add-genesis-account $(simd keys show validator -a --keyring-backend=test --home=$HOME/.simd) 1000000000validatortoken,1000000000stake --home=$HOME/.simd
simd gentx validator --keyring-backend=test --home=$HOME/.simd --chain-id testing
simd collect-gentxs --home=$HOME/.simd

simd start --home=$HOME/.simd

Open another terminal and run

simd keys add user1 --keyring-backend=test --home=$HOME/.simd
simd tx bank send $(simd keys show -a validator --keyring-backend=test --home=$HOME/.simd) $(simd keys show -a user1 --keyring-backend=test --home=$HOME/.simd) 1000stake --keyring-backend=test --home=$HOME/.simd --chain-id=testing --generate-only > my_tx.json
simd tx sign my_tx.json --from validator --keyring-backend=test --home=$HOME/.simd --chain-id=testing --signature-only

Result

{"signatures":[]}

Expected

{"signatures":[{XXXXX}]}

[gsora]

Tried reproducing this bug on latest Launchpad release.

cncli tx send did:com:1l9rr5ck7ed30ny3ex4uj75ezrt03gfp96z7nen (cncli keys show janet --address)  2000000000ucommercio --chain-id=testnet --fees 10000ucommercio -y --generate-only

cncli tx sign tx --from jack  --chain-id=testnet  --signature-only

(jack == did:com:1l9rr5ck7ed30ny3ex4uj75ezrt03gfp96z7nen in this context)

The output of the last command looks like a proper signature:

{"pub_key":{"type":"tendermint/PubKeySecp256k1","value":"A7Xdk942ZzsO14tioIjksOlmccYvnUJi8z+ytZ9qaK4h"},"signature":"poVIjzoFMfg1kV3rOVugpMBC5RaH738NW8xz0DeYftlpuYIVeyfxmZfkZ0d38BzPxY9MCrmAO+K5jN0cQIfPVQ=="}

[alessio]

Thanks @gsora! It's a regression 👍

[clevinson]

Of note from SDK iteration planning call:

• let's make sure we are issuing an error whenever a user uses SIGN_MODE_DIRECT when singing multisig or multiple signature transactinos. Only amino-json is supported a a sign method for these currently.