[TUI] block hashes in TUI will need to be larger than first 8 chars for mainnet

[antiochp]

John Tromp @tromp 15:30
btw, the TUI only shows 8 hex digits of hash

jaspervdm @jaspervdm 15:31
or 5 even

John Tromp @tromp 15:31
that won't cut it on mainnet, where most will be 0

[antiochp]

Commented on #2325 but commenting here as well -

We should scope this beyond the tui to include everywhere we display a block hash - api, logs etc.
i.e. We should probably modify the default formatter for Hash.

Having a big bunch of 0s prefixing a block hash is a real pain for display purposes...

---

Random thought (ignoring the fact we are 6 days from mainnet) -

If a block hash is effectively -

• hash(pow)

Would it be possible to reference blocks via -

• hash(hash(pow))

Is there any reason this wouldn't work or would make things significantly more complex?

[tromp]

there's no need to hash twice. the options are either to show

1. around 10 to 13 hex digits, of which the first 5 would normally be 0, leaving 5 to 8 useful ones.
2. the show the last 8 hex digits

[antiochp]

Is there an option 3 here as well - just strip off the 0 prefix and show the first 8 useful digits?

[antiochp]

If we implement whatever logic we go with here -

grin/core/src/core/hash.rs

Lines 39 to 52 in 5915580

	impl fmt::Debug for Hash {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	for i in self.0[..4].iter() {
	write!(f, "{:02x}", i)?;
	}
	Ok(())
	}
	}
	impl fmt::Display for Hash {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	fmt::Debug::fmt(self, f)
	}
	}

Then we should be able to simply print block.hash() directly everywhere and have it do the right thing.

[tromp]

Stripping off all leading zeroes is an option, but feels like a hack to me. My preference is for option 1 with 12 hex digits, i.e. the first 48 bits of hash. The 5 leading 0s is like a sanity check that you're dealing with a blockhash.

[eupn]

@tromp how about this? Show twice as less starting zeroes and some digits from the end.

[antiochp]

OK I vote for what @tromp suggested as option 1 - keep it really simple and show the first 12 digits.

I like the idea of the sanity check.
I also prefer seeing the first digits (vs. the last digits) as its easier to compare visually against full block hashes displayed elsewhere, like block explorers in the browser etc.

[tromp]

@eupn that is more than 12 chars in total and harder to cut and paste, as double-clicking will not select across the dots.