How gnosis safe's pending transactions execution works?

Question

I was looking into allowing users to create new transactions instead of creating a rejection transaction for a pending transaction. So, I was just creating some transactions to understand few things and executing them without order and the one thing I observed is like this - I created 3 simple eth transfer transactions with different values to send:

Pending:

1. value: 0.2 eth, nonce: 6, safeTxHash: 0xb26d79300880f9a7d05e12c231538ff56f9685c9fd31f76492c2330c45f5cfa5
2. value: 0.04 eth, nonce: 7, safeTxHash: 0xd1f5018fc1d0f816fefac955e94291c9498735ba6665a59576bfd771f9bdd8ed
3. value: 0.03 eth, nonce: 8, safeTxHash: 0xbf9181ffd31c02ef1d9f096ae7012649163f48fd8cfe18add810748210a3a614

Now, I executed transaction number 3 with nonce 8 and the result on gnosis safe UI is like this:

Completed:

1. value: 0.03, nonce: 6, safeTxHash: 0x04c0db5544ed6f94bd8e5b8614fef767560f30a3eed16f54d97119f4430390f2

Pending:

1. value: 0.04 eth, nonce: 7, safeTxHash: 0xd1f5018fc1d0f816fefac955e94291c9498735ba6665a59576bfd771f9bdd8ed
2. value: 0.03 eth, nonce: 8, safeTxHash: 0xbf9181ffd31c02ef1d9f096ae7012649163f48fd8cfe18add810748210a3a614

Now, I am not able to understand how a new transaction is created with different nonce and safeTxHash and when it took my signature because I just executed the execute transaction function of the safe core SDK with transaction number 3 with nonce 8 as the input(safeTransaction).

Safe Address: 0xb38Ab20B83bA37B898FDB212283241d278282924 Testnet: Rinkeby

Answer 1

You ran into a special case of the Safe when you have Safe woth threshold 1 and use the msg.sender to confirm the signature (see https://github.com/gnosis/safe-contracts/issues/187).

To avoid this you should use a Safe with threshold > 1 or don't use the msg.sender based signatures.