Feature request: Unique time.Now() per transaction

[jefft0]

Description

I understand that time.Now() returns the same value for every call within a transaction (the block time). But there can be multiple transactions in a block. It would be useful for time.Now() to return different values for each transaction. (For example each call to r/demo/boards to post a message would give a unique message timestamp.) I tried the following goland code which calls time.Now() twice in quick succession:

func main() {
	t1 := time.Now()
	t2 := time.Now()
	fmt.Println(t1.String())
	fmt.Println(t2.String())
}

It prints:

2024-02-29 14:05:33.265165 +0100 CET m=+0.000095043
2024-02-29 14:05:33.265165 +0100 CET m=+0.000095126

As you can see, even this returns unique values. Go developers may expect this to some extent.

Possible implementation

On a dev call, @moul suggested making each transaction offset the value of time.Now() using the transaction index within the block. For example, timestamp + tx.index * 100us . (The example value of 100us should be configured based on block time and max transactions per block so that a time.Now() value won't overlap with the next block.)

[moul]

Just to make sure that we're aligned, here is what I expect:

TX1

func CallMe() {
	t1 := time.Now()
	t2 := time.Now()
	fmt.Println(t1.String())
	fmt.Println(t2.String())
}
// Output:
// 2024-02-29 14:05:33.265165 +0100 CET m=+0.000095043
// 2024-02-29 14:05:33.265165 +0100 CET m=+0.000095043

---

TX2:

func CallMe() {
	t1 := time.Now()
	t2 := time.Now()
	fmt.Println(t1.String())
	fmt.Println(t2.String())
}
// Output:
// 2024-02-29 14:05:33.265165 +0100 CET m=+0.000095126
// 2024-02-29 14:05:33.265165 +0100 CET m=+0.000095126

---

The key is not within a single TX but between independent TXs. Within a single TX, consistency is currently preferred.

[Kouteki]

We won't be handling this feature request before the mainnet launch, primarily due to the bandwidth issues. Will keep open and possibly revisit in the future.