Reject close of active vote accounts (#22651)

* 10461 Reject close of vote accounts unless it earned no credits in the previous epoch. This is checked by comparing current epoch (from clock sysvar) with the most recent epoch with credits in vote state.

sdk/program/src/instruction.rs

@@ -252,6 +252,10 @@ pub enum InstructionError {
     /// Accounts data budget exceeded
     #[error("Requested account data allocation exceeded the accounts data budget")]
     AccountsDataBudgetExceeded,
+
+    /// Active vote account close
+    #[error("Cannot close vote account unless it stopped voting at least one full epoch ago")]
+    ActiveVoteAccountClose,
     // Note: For any new error added here an equivalent ProgramError and its
     // conversions must also be added
 }

sdk/program/src/program_error.rs

@@ -51,6 +51,8 @@ pub enum ProgramError {
     IllegalOwner,
     #[error("Requested account data allocation exceeded the accounts data budget")]
     AccountsDataBudgetExceeded,
+    #[error("Cannot close vote account unless it stopped voting at least one full epoch ago")]
+    ActiveVoteAccountClose,
 }
 
 pub trait PrintProgramError {
@@ -90,6 +92,7 @@ impl PrintProgramError for ProgramError {
             Self::UnsupportedSysvar => msg!("Error: UnsupportedSysvar"),
             Self::IllegalOwner => msg!("Error: IllegalOwner"),
             Self::AccountsDataBudgetExceeded => msg!("Error: AccountsDataBudgetExceeded"),
+            Self::ActiveVoteAccountClose => msg!("Error: ActiveVoteAccountClose"),
         }
     }
 }
@@ -121,6 +124,7 @@ pub const ACCOUNT_NOT_RENT_EXEMPT: u64 = to_builtin!(16);
 pub const UNSUPPORTED_SYSVAR: u64 = to_builtin!(17);
 pub const ILLEGAL_OWNER: u64 = to_builtin!(18);
 pub const ACCOUNTS_DATA_BUDGET_EXCEEDED: u64 = to_builtin!(19);
+pub const ACTIVE_VOTE_ACCOUNT_CLOSE: u64 = to_builtin!(20);
 // Warning: Any new program errors added here must also be:
 // - Added to the below conversions
 // - Added as an equivilent to InstructionError
@@ -148,6 +152,7 @@ impl From<ProgramError> for u64 {
             ProgramError::UnsupportedSysvar => UNSUPPORTED_SYSVAR,
             ProgramError::IllegalOwner => ILLEGAL_OWNER,
             ProgramError::AccountsDataBudgetExceeded => ACCOUNTS_DATA_BUDGET_EXCEEDED,
+            ProgramError::ActiveVoteAccountClose => ACTIVE_VOTE_ACCOUNT_CLOSE,
             ProgramError::Custom(error) => {
                 if error == 0 {
                     CUSTOM_ZERO
@@ -181,6 +186,7 @@ impl From<u64> for ProgramError {
             UNSUPPORTED_SYSVAR => Self::UnsupportedSysvar,
             ILLEGAL_OWNER => Self::IllegalOwner,
             ACCOUNTS_DATA_BUDGET_EXCEEDED => Self::AccountsDataBudgetExceeded,
+            ACTIVE_VOTE_ACCOUNT_CLOSE => Self::ActiveVoteAccountClose,
             _ => Self::Custom(error as u32),
         }
     }
@@ -210,6 +216,7 @@ impl TryFrom<InstructionError> for ProgramError {
             Self::Error::UnsupportedSysvar => Ok(Self::UnsupportedSysvar),
             Self::Error::IllegalOwner => Ok(Self::IllegalOwner),
             Self::Error::AccountsDataBudgetExceeded => Ok(Self::AccountsDataBudgetExceeded),
+            Self::Error::ActiveVoteAccountClose => Ok(Self::ActiveVoteAccountClose),
             _ => Err(error),
         }
     }
@@ -241,6 +248,7 @@ where
             UNSUPPORTED_SYSVAR => Self::UnsupportedSysvar,
             ILLEGAL_OWNER => Self::IllegalOwner,
             ACCOUNTS_DATA_BUDGET_EXCEEDED => Self::AccountsDataBudgetExceeded,
+            ACTIVE_VOTE_ACCOUNT_CLOSE => Self::ActiveVoteAccountClose,
             _ => {
                 // A valid custom error has no bits set in the upper 32
                 if error >> BUILTIN_BIT_SHIFT == 0 {