Fix - `test_feature_activation_loaded_programs_recompilation_phase()` (#35299)

* Fixes test_feature_activation_loaded_programs_recompilation_phase() to trigger the recompilation phase before the epoch boundary.

* Adds a direct check of the cached entries around recompilation.

program-runtime/src/loaded_programs.rs

@@ -1079,6 +1079,14 @@ impl<FG: ForkGraph> LoadedPrograms<FG> {
         }
     }
 
+    /// Returns the `slot_versions` of the second level for the given program id.
+    pub fn get_slot_versions_for_tests(&self, key: &Pubkey) -> &[Arc<LoadedProgram>] {
+        self.entries
+            .get(key)
+            .map(|second_level| second_level.slot_versions.as_ref())
+            .unwrap_or(&[])
+    }
+
     /// This function removes the given entry for the given program from the cache.
     /// The function expects that the program and entry exists in the cache. Otherwise it'll panic.
     fn unload_program_entry(&mut self, program: &Pubkey, remove_entry: &Arc<LoadedProgram>) {

runtime/src/bank/tests.rs

@@ -11884,12 +11884,6 @@ fn test_feature_activation_loaded_programs_recompilation_phase() {
         .remove(&feature_set::reject_callx_r10::id());
     let (root_bank, bank_forks) = Bank::new_with_bank_forks_for_tests(&genesis_config);
 
-    // Test a basic transfer
-    let amount = genesis_config.rent.minimum_balance(0);
-    let pubkey = solana_sdk::pubkey::new_rand();
-    root_bank.transfer(amount, &mint_keypair, &pubkey).unwrap();
-    assert_eq!(root_bank.get_balance(&pubkey), amount);
-
     // Program Setup
     let program_keypair = Keypair::new();
     let program_data =
@@ -11903,26 +11897,19 @@ fn test_feature_activation_loaded_programs_recompilation_phase() {
     });
     root_bank.store_account(&program_keypair.pubkey(), &program_account);
 
-    // Compose instruction using the desired program
-    let instruction1 = Instruction::new_with_bytes(program_keypair.pubkey(), &[], Vec::new());
-    let message1 = Message::new(&[instruction1], Some(&mint_keypair.pubkey()));
-    let binding1 = mint_keypair.insecure_clone();
-    let signers1 = vec![&binding1];
-    let transaction1 = Transaction::new(&signers1, message1, root_bank.last_blockhash());
+    // Compose message using the desired program.
+    let instruction = Instruction::new_with_bytes(program_keypair.pubkey(), &[], Vec::new());
+    let message = Message::new(&[instruction], Some(&mint_keypair.pubkey()));
+    let binding = mint_keypair.insecure_clone();
+    let signers = vec![&binding];
 
-    // Advance the bank so the next transaction can be submitted.
+    // Advance the bank so that the program becomes effective.
     goto_end_of_slot(root_bank.clone());
     let bank = new_from_parent_with_fork_next_slot(root_bank, bank_forks.as_ref());
 
-    // Compose second instruction using the same program with a different block hash
-    let instruction2 = Instruction::new_with_bytes(program_keypair.pubkey(), &[], Vec::new());
-    let message2 = Message::new(&[instruction2], Some(&mint_keypair.pubkey()));
-    let binding2 = mint_keypair.insecure_clone();
-    let signers2 = vec![&binding2];
-    let transaction2 = Transaction::new(&signers2, message2, bank.last_blockhash());
-
-    // Execute before feature is enabled to get program into the cache.
-    let result_without_feature_enabled = bank.process_transaction(&transaction1);
+    // Load the program with the old environment.
+    let transaction = Transaction::new(&signers, message.clone(), bank.last_blockhash());
+    let result_without_feature_enabled = bank.process_transaction(&transaction);
     assert_eq!(
         result_without_feature_enabled,
         Err(TransactionError::InstructionError(
@@ -11931,7 +11918,7 @@ fn test_feature_activation_loaded_programs_recompilation_phase() {
         ))
     );
 
-    // Activate feature
+    // Schedule feature activation to trigger a change of environment at the epoch boundary.
     let feature_account_balance =
         std::cmp::max(genesis_config.rent.minimum_balance(Feature::size_of()), 1);
     bank.store_account(
@@ -11939,12 +11926,59 @@ fn test_feature_activation_loaded_programs_recompilation_phase() {
         &feature::create_account(&Feature { activated_at: None }, feature_account_balance),
     );
 
+    // Advance the bank to middle of epoch to start the recompilation phase.
     goto_end_of_slot(bank.clone());
-    // Advance to next epoch, which starts the recompilation phase
-    let bank = new_from_parent_next_epoch(bank, bank_forks.as_ref(), 1);
+    let bank = new_bank_from_parent_with_bank_forks(&bank_forks, bank, &Pubkey::default(), 16);
+    let current_env = bank
+        .loaded_programs_cache
+        .read()
+        .unwrap()
+        .get_environments_for_epoch(0)
+        .program_runtime_v1
+        .clone();
+    let upcoming_env = bank
+        .loaded_programs_cache
+        .read()
+        .unwrap()
+        .get_environments_for_epoch(1)
+        .program_runtime_v1
+        .clone();
 
-    // Execute after feature is enabled to check it was filtered out and reverified.
-    let result_with_feature_enabled = bank.process_transaction(&transaction2);
+    // Advance the bank to recompile the program.
+    {
+        let loaded_programs_cache = bank.loaded_programs_cache.read().unwrap();
+        let slot_versions =
+            loaded_programs_cache.get_slot_versions_for_tests(&program_keypair.pubkey());
+        assert_eq!(slot_versions.len(), 1);
+        assert!(Arc::ptr_eq(
+            slot_versions[0].program.get_environment().unwrap(),
+            &current_env
+        ));
+    }
+    goto_end_of_slot(bank.clone());
+    let bank = new_from_parent_with_fork_next_slot(bank, bank_forks.as_ref());
+    {
+        let loaded_programs_cache = bank.loaded_programs_cache.read().unwrap();
+        let slot_versions =
+            loaded_programs_cache.get_slot_versions_for_tests(&program_keypair.pubkey());
+        assert_eq!(slot_versions.len(), 2);
+        assert!(Arc::ptr_eq(
+            slot_versions[0].program.get_environment().unwrap(),
+            &current_env
+        ));
+        assert!(Arc::ptr_eq(
+            slot_versions[1].program.get_environment().unwrap(),
+            &upcoming_env
+        ));
+    }
+
+    // Advance the bank to cross the epoch boundary and activate the feature.
+    goto_end_of_slot(bank.clone());
+    let bank = new_bank_from_parent_with_bank_forks(&bank_forks, bank, &Pubkey::default(), 33);
+
+    // Load the program with the new environment.
+    let transaction = Transaction::new(&signers, message, bank.last_blockhash());
+    let result_with_feature_enabled = bank.process_transaction(&transaction);
     assert_eq!(
         result_with_feature_enabled,
         Err(TransactionError::InstructionError(