Use explicit u8 when assigning a byte slice

[junderw]

Is there a way to tell the compiler to not allow [0; 64] and require that either the type is explicitly given to the variable, or that each member uses explicit 0u8 notation?

I noticed the usage was a mix of explicit and implicit, so I changed all to explicit.

[real-or-random]

Is there a way to tell the compiler to not allow [0; 64] and require that either the type is explicitly given to the variable, or that each member uses explicit 0u8 notation?

It's maybe useful as a formatting convention but it shouldn't add too much:

If an integer type can be uniquely determined from the surrounding program context, the unsuffixed integer literal has that type.

(https://doc.rust-lang.org/stable/reference/tokens.html#number-literals)

[apoelstra]

ACK 24d6f62

Agreed that it's clearer this way and I wish there was a way to lint for it.

[thomaseizinger]

I noticed the usage was a mix of explicit and implicit, so I changed all to explicit.

Was there a rationale for not dealing with the following occurrences?

❯ git grep -e '\[0;' master
master:secp256k1-sys/src/lib.rs:        Self::from_array_unchecked([0; 64])
master:secp256k1-sys/src/lib.rs:        Self::from_array_unchecked([0; 64])
master:secp256k1-sys/src/lib.rs:        Self::from_array_unchecked([0; 64])
master:secp256k1-sys/src/lib.rs:        Self::from_array_unchecked([0; 96])
master:secp256k1-sys/src/lib.rs:    static mut PREALLOCATED_CONTEXT: [u8; CTX_SIZE] = [0; CTX_SIZE];
master:secp256k1-sys/src/recovery.rs:    pub fn new() -> RecoverableSignature { RecoverableSignature([0; 65]) }
master:src/key.rs:            let mut result = vec![0; $hex.len() / 2];
master:src/key.rs:        assert_eq!(SecretKey::from_slice(&[0; 32]), Err(InvalidSecretKey));
master:src/key.rs:            PublicKey::from_slice(&[0; constants::PUBLIC_KEY_SIZE - 1]),
master:src/key.rs:            PublicKey::from_slice(&[0; constants::PUBLIC_KEY_SIZE + 1]),
master:src/key.rs:            PublicKey::from_slice(&[0; constants::UNCOMPRESSED_PUBLIC_KEY_SIZE - 1]),
master:src/key.rs:            PublicKey::from_slice(&[0; constants::UNCOMPRESSED_PUBLIC_KEY_SIZE + 1]),
master:src/key.rs:            SecretKey::from_slice(&[0; constants::SECRET_KEY_SIZE - 1]),
master:src/key.rs:            SecretKey::from_slice(&[0; constants::SECRET_KEY_SIZE + 1]),
master:src/lib.rs:            let mut result = vec![0; $hex.len() / 2];
master:src/lib.rs:        assert_eq!(Signature::from_der(&[0; constants::MAX_SIGNATURE_SIZE + 1]),
master:src/lib.rs:        assert_eq!(Signature::from_der(&[0; constants::MAX_SIGNATURE_SIZE]),
master:src/lib.rs:        assert_eq!(Message::from_slice(&[0; constants::MESSAGE_SIZE - 1]),
master:src/lib.rs:        assert_eq!(Message::from_slice(&[0; constants::MESSAGE_SIZE + 1]),
master:src/lib.rs:        assert!(Message::from_slice(&[0; constants::MESSAGE_SIZE]).is_ok());
master:src/recovery.rs:        let sig = RecoverableSignature::from_compact(&[0; 64], RecoveryId(0)).unwrap();
master:src/schnorrsig.rs:            PublicKey::from_slice(&[0; constants::SCHNORRSIG_PUBLIC_KEY_SIZE - 1]),
master:src/schnorrsig.rs:            PublicKey::from_slice(&[0; constants::SCHNORRSIG_PUBLIC_KEY_SIZE + 1]),

Asking because I am currently rebasing #327 and when trying to re-apply my changes on top of this, I noticed that a simple search and replace hit more lines than I expected.

[junderw]

I probably should have documented the command I used to get what I did.

I definitely intended to replace all.

If you don't want to make another PR I can.

Thanks for the catch.

[apoelstra]

I guess we could write a shell script that runs this grep command in CI.