Extract pubkey crate

[kevinheavey]

Problem

solana_program::pubkey can get its own crate once #2015 is merged

Summary of Changes

• move pubkey.rs to its own crate and re-export in solana-program
• move relevant syscall definitions to the new crate and re-export them in their old location
• make the code requiring curve25519-dalek and sha2 optional (these are methods so they can't be moved to separate crates)
• make bytemuck and serde optional
• make std optional but enable it by default

[mergify]

The Firedancer team maintains a line-for-line reimplementation of the
native programs, and until native programs are moved to BPF, those
implementations must exactly match their Agave counterparts.
If this PR represents a change to a native program implementation (not
tests), please include a reviewer from the Firedancer team. And please
keep refactors to a minimum.

[kevinheavey]

For checking the feature powerset I've used cargo hack check --feature-powerset --exclude-features frozen-abi --all-targets and cargo hack check --feature-powerset --exclude-features frozen-abi --all-targets --at-least-one-of 'std,' --target wasm32-unknown-unknown

[joncinque]

Looks really good overall! Mostly small things

[joncinque]

Same as with the other FromPrimitive implementation, is there a way to add an exhaustiveness check? If not, would you mind adding a simple test to make sure that the conversion works? ie

        macro_rules! ensure_mapping {
            ($ty: path, $($num: literal => $variant: path),+ $(,)?) => {
                // assert that the given values produce the expected variants
                $(assert_eq!(<$ty>::from($num), $variant);)+
                $(assert_eq!(<$ty>::from_i64($num), Some($variant));)+
                $(assert_eq!(<$ty>::from_u64($num), Some($variant));)+

                // this generated fn will never be called but will produce a
                // non-exhaustive pattern error if you've missed a variant
                #[allow(dead_code)]
                fn check_all_covered(err: $ty) {
                    match err {
                        $($variant => {})+
                    };
                }
            }
        }
    #[test]
    fn test_exhaustive_conversion() {
        ensure_mapping! {
            PubkeyError,
            0 => PubkeyError::MaxSeedLengthExceeded,
            1 => PubkeyError::InvalidSeeds,
            2 => PubkeyError::IllegalOwner,
        }
        ensure_mapping! {
            ParsePubkeyError,
            0 => ParsePubkeyError::WrongSize,
            1 => ParsePubkeyError::Invalid,
        }
    }

You'll need to add a From<u64> implementation for ParsePubkeyError to get this to work, unless you have a more clever way to only do that check for the first enum

[kevinheavey]

I used strum to iterate through variants and check that strum's from_repr matches our from_i64:

for variant in PubkeyError::iter() {
    let variant_i64 = variant as i64;
    assert_eq!(
        PubkeyError::from_repr(variant_i64 as usize),
        PubkeyError::from_i64(variant_i64)
    );
}

[joncinque]

Side note for me: this is fine for now, but we should restore these stubs at some point, probably through a new crate which just contains the stubs.

[joncinque]

One last bit, then this is good to go on my side! @yihau , can you accept ownership of solana-pubkey?

[joncinque]

Looks great, thanks! I'll approve once the crate check passes

[yihau]

crate-check passed!

[joncinque]

Great work, thanks for the contribution!