Cleanup unsupported sysvars (#16390)

* Cleanup unsupported sysvars

* fix ser description

programs/bpf/rust/sysvar/src/lib.rs

@@ -7,11 +7,12 @@ use solana_program::{
     entrypoint,
     entrypoint::ProgramResult,
     msg,
+    program_error::ProgramError,
     pubkey::Pubkey,
     rent,
     sysvar::{
-        self, clock::Clock, fees::Fees, rent::Rent, slot_hashes::SlotHashes,
-        stake_history::StakeHistory, Sysvar,
+        self, clock::Clock, fees::Fees, instructions, rent::Rent, slot_hashes::SlotHashes,
+        slot_history::SlotHistory, stake_history::StakeHistory, Sysvar,
     },
 };
 
@@ -25,37 +26,54 @@ fn process_instruction(
     // Clock
     msg!("Clock identifier:");
     sysvar::clock::id().log();
-    let clock = Clock::from_account_info(&accounts[2]).expect("clock");
+    let clock = Clock::from_account_info(&accounts[2]).unwrap();
     assert_eq!(clock.slot, DEFAULT_SLOTS_PER_EPOCH + 1);
 
     // Fees
     msg!("Fees identifier:");
     sysvar::fees::id().log();
-    let fees = Fees::from_account_info(&accounts[3]).expect("fees");
+    let fees = Fees::from_account_info(&accounts[3]).unwrap();
     let fee_calculator = fees.fee_calculator;
     assert_eq!(fee_calculator.lamports_per_signature, 0);
 
+    // Instructions
+    msg!("Instructions identifier:");
+    sysvar::instructions::id().log();
+    let index = instructions::load_current_index(&accounts[4].try_borrow_data()?);
+    assert_eq!(0, index);
+    msg!(
+        "instruction {:?}",
+        instructions::load_instruction_at(index as usize, &accounts[4].try_borrow_data()?)
+    );
+
+    let due = Rent::from_account_info(&accounts[5]).unwrap().due(
+        rent::DEFAULT_LAMPORTS_PER_BYTE_YEAR * rent::DEFAULT_EXEMPTION_THRESHOLD as u64,
+        1,
+        1.0,
+    );
+    assert_eq!(due, (0, true));
+
     // Slot Hashes
     msg!("SlotHashes identifier:");
     sysvar::slot_hashes::id().log();
-    let slot_hashes = SlotHashes::from_account_info(&accounts[4]).expect("slot_hashes");
-    assert!(slot_hashes.len() >= 1);
+    assert_eq!(
+        Err(ProgramError::UnsupportedSysvar),
+        SlotHashes::from_account_info(&accounts[6])
+    );
+
+    // Slot History
+    msg!("SlotHistory identifier:");
+    sysvar::slot_history::id().log();
+    assert_eq!(
+        Err(ProgramError::UnsupportedSysvar),
+        SlotHistory::from_account_info(&accounts[7])
+    );
 
     // Stake History
     msg!("StakeHistory identifier:");
     sysvar::stake_history::id().log();
-    let stake_history = StakeHistory::from_account_info(&accounts[5]).expect("stake_history");
+    let stake_history = StakeHistory::from_account_info(&accounts[8]).unwrap();
     assert!(stake_history.len() >= 1);
 
-    let rent = Rent::from_account_info(&accounts[6]).unwrap();
-    assert_eq!(
-        rent.due(
-            rent::DEFAULT_LAMPORTS_PER_BYTE_YEAR * rent::DEFAULT_EXEMPTION_THRESHOLD as u64,
-            1,
-            1.0
-        ),
-        (0, true)
-    );
-
     Ok(())
 }