make voter_pubkey a function of epoch (#5830)

* make voter_pubkey a function of epoch

* fixups

programs/budget_api/src/budget_instruction.rs

@@ -1,13 +1,39 @@
-use crate::budget_expr::BudgetExpr;
-use crate::budget_state::BudgetState;
-use crate::id;
+use crate::{budget_expr::BudgetExpr, budget_state::BudgetState, id};
 use bincode::serialized_size;
 use chrono::prelude::{DateTime, Utc};
+use num_derive::FromPrimitive;
 use serde_derive::{Deserialize, Serialize};
-use solana_sdk::hash::Hash;
-use solana_sdk::instruction::{AccountMeta, Instruction};
-use solana_sdk::pubkey::Pubkey;
-use solana_sdk::system_instruction;
+use solana_sdk::{
+    hash::Hash,
+    instruction::{AccountMeta, Instruction},
+    instruction_processor_utils::DecodeError,
+    pubkey::Pubkey,
+    system_instruction,
+};
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, FromPrimitive)]
+pub enum BudgetError {
+    DestinationMissing,
+}
+
+impl<T> DecodeError<T> for BudgetError {
+    fn type_of() -> &'static str {
+        "BudgetError"
+    }
+}
+
+impl std::fmt::Display for BudgetError {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                BudgetError::DestinationMissing => "destination missing",
+            }
+        )
+    }
+}
+impl std::error::Error for BudgetError {}
 
 /// A smart contract.
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]

programs/budget_api/src/budget_processor.rs

@@ -1,14 +1,15 @@
 //! budget program
-use crate::budget_expr::Witness;
-use crate::budget_instruction::BudgetInstruction;
-use crate::budget_state::{BudgetError, BudgetState};
+use crate::{
+    budget_expr::Witness,
+    budget_instruction::{BudgetError, BudgetInstruction},
+    budget_state::BudgetState,
+};
 use bincode::deserialize;
 use chrono::prelude::{DateTime, Utc};
 use log::*;
-use solana_sdk::account::KeyedAccount;
-use solana_sdk::hash::hash;
-use solana_sdk::instruction::InstructionError;
-use solana_sdk::pubkey::Pubkey;
+use solana_sdk::{
+    account::KeyedAccount, hash::hash, instruction::InstructionError, pubkey::Pubkey,
+};
 
 /// Process a Witness Signature. Any payment plans waiting on this signature
 /// will progress one step.

programs/budget_api/src/budget_state.rs

@@ -1,28 +1,8 @@
 //! budget state
 use crate::budget_expr::BudgetExpr;
 use bincode::{self, deserialize, serialize_into};
-use num_derive::FromPrimitive;
 use serde_derive::{Deserialize, Serialize};
 use solana_sdk::instruction::InstructionError;
-use solana_sdk::instruction_processor_utils::DecodeError;
-
-#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, FromPrimitive)]
-pub enum BudgetError {
-    DestinationMissing,
-}
-
-impl<T> DecodeError<T> for BudgetError {
-    fn type_of() -> &'static str {
-        "BudgetError"
-    }
-}
-
-impl std::fmt::Display for BudgetError {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        write!(f, "error")
-    }
-}
-impl std::error::Error for BudgetError {}
 
 #[derive(Serialize, Deserialize, Debug, Clone, Default, PartialEq)]
 pub struct BudgetState {