init errors

program/Cargo.toml

@@ -22,6 +22,7 @@ serde = { version = "1.0.193", features = ["derive"] }
 solana-frozen-abi-macro = "1.18.2"
 solana-frozen-abi = "1.18.2"
 solana-program = "1.18.2"
+spl-program-error = "0.3.1"
 
 [lib]
 crate-type = ["cdylib", "lib"]

program/src/error.rs

@@ -0,0 +1,103 @@
+//! Vote program errors
+
+use spl_program_error::*;
+
+/// Reasons the vote might have had an error
+#[spl_program_error]
+pub enum VoteError {
+    #[error("vote already recorded or not in slot hashes history")]
+    VoteTooOld,
+
+    #[error("vote slots do not match bank history")]
+    SlotsMismatch,
+
+    #[error("vote hash does not match bank hash")]
+    SlotHashMismatch,
+
+    #[error("vote has no slots, invalid")]
+    EmptySlots,
+
+    #[error("vote timestamp not recent")]
+    TimestampTooOld,
+
+    #[error("authorized voter has already been changed this epoch")]
+    TooSoonToReauthorize,
+
+    // TODO: figure out how to migrate these new errors
+    #[error("Old state had vote which should not have been popped off by vote in new state")]
+    LockoutConflict,
+
+    #[error("Proposed state had earlier slot which should have been popped off by later vote")]
+    NewVoteStateLockoutMismatch,
+
+    #[error("Vote slots are not ordered")]
+    SlotsNotOrdered,
+
+    #[error("Confirmations are not ordered")]
+    ConfirmationsNotOrdered,
+
+    #[error("Zero confirmations")]
+    ZeroConfirmations,
+
+    #[error("Confirmation exceeds limit")]
+    ConfirmationTooLarge,
+
+    #[error("Root rolled back")]
+    RootRollBack,
+
+    #[error("Confirmations for same vote were smaller in new proposed state")]
+    ConfirmationRollBack,
+
+    #[error("New state contained a vote slot smaller than the root")]
+    SlotSmallerThanRoot,
+
+    #[error("New state contained too many votes")]
+    TooManyVotes,
+
+    #[error("every slot in the vote was older than the SlotHashes history")]
+    VotesTooOldAllFiltered,
+
+    #[error("Proposed root is not in slot hashes")]
+    RootOnDifferentFork,
+
+    #[error("Cannot close vote account unless it stopped voting at least one full epoch ago")]
+    ActiveVoteAccountClose,
+
+    #[error("Cannot update commission at this point in the epoch")]
+    CommissionUpdateTooLate,
+}
+
+#[cfg(test)]
+mod tests {
+    use {
+        super::*,
+        solana_program::{decode_error::DecodeError, program_error::ProgramError},
+    };
+
+    #[test]
+    fn test_custom_error_decode_to_program_error() {
+        use num_traits::FromPrimitive;
+        fn pretty_err<T>(err: ProgramError) -> String
+        where
+            T: 'static + std::error::Error + DecodeError<T> + FromPrimitive,
+        {
+            if let ProgramError::Custom(code) = err {
+                let specific_error: T = T::decode_custom_error_to_enum(code).unwrap();
+                format!(
+                    "{:?}: {}::{:?} - {}",
+                    err,
+                    T::type_of(),
+                    specific_error,
+                    specific_error,
+                )
+            } else {
+                "".to_string()
+            }
+        }
+        assert_eq!(
+            "Custom(0): VoteError::VoteTooOld - vote already recorded or not in slot hashes \
+             history",
+            pretty_err::<VoteError>(VoteError::VoteTooOld.into())
+        )
+    }
+}

program/src/lib.rs

@@ -5,6 +5,7 @@
 
 #[cfg(all(target_os = "solana", feature = "bpf-entrypoint"))]
 mod entrypoint;
+pub mod error;
 
 // [Core BPF]: TODO: Program-test will not overwrite existing built-ins.
 // See https://github.com/solana-labs/solana/pull/35233.