Ensure that the spl-token 2 native mint account is owned by the spl-t…

…oken 2 program.

Workaround for solana-labs/solana-program-library#374 until spl-token 3 is shipped

runtime/src/bank.rs

@@ -71,6 +71,29 @@ use std::{
     sync::{Arc, RwLock, RwLockReadGuard},
 };
 
+// Partial SPL Token v2.0.x declarations inlined to avoid an external dependency on the spl-token crate
+pub mod inline_spl_token_v2_0 {
+    solana_sdk::declare_id!("TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA");
+    pub mod native_mint {
+        solana_sdk::declare_id!("So11111111111111111111111111111111111111112");
+
+        /*
+            Mint {
+                mint_authority: COption::None,
+                supply: 0,
+                decimals: 9,
+                is_initialized: true,
+                freeze_authority: COption::None,
+            }
+        */
+        pub const ACCOUNT_DATA: [u8; 82] = [
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        ];
+    }
+}
+
 pub const SECONDS_PER_YEAR: f64 = 365.25 * 24.0 * 60.0 * 60.0;
 
 pub const MAX_LEADER_SCHEDULE_STAKES: Epoch = 5;
@@ -3208,6 +3231,7 @@ impl Bank {
         self.reinvoke_entered_epoch_callback(initiate_callback);
         self.recheck_cross_program_support();
         self.recheck_compute_budget();
+        self.reconfigure_token2_native_mint();
     }
 
     fn ensure_builtins(&mut self, init_or_warp: bool) {
@@ -3257,6 +3281,39 @@ impl Bank {
         self.set_compute_budget(compute_budget);
     }
 
+    fn reconfigure_token2_native_mint(self: &mut Bank) {
+        let reconfigure_token2_native_mint = match self.operating_mode() {
+            OperatingMode::Development => true,
+            OperatingMode::Preview => self.epoch() == 93,
+            OperatingMode::Stable => self.epoch() >= 74,
+        };
+
+        if reconfigure_token2_native_mint {
+            let mut native_mint_account = solana_sdk::account::Account {
+                owner: inline_spl_token_v2_0::id(),
+                data: inline_spl_token_v2_0::native_mint::ACCOUNT_DATA.to_vec(),
+                lamports: 1000000000, // 1 SOL
+                executable: false,
+                rent_epoch: self.epoch() + 1,
+            };
+
+            // As a workaround for
+            // https://github.com/solana-labs/solana-program-library/issues/374, ensure that the
+            // spl-token 2 native mint account is owned by the spl-token 2 program.
+            if let Some(existing_native_mint_account) =
+                self.get_account(&inline_spl_token_v2_0::native_mint::id())
+            {
+                if existing_native_mint_account.owner == solana_sdk::system_program::id() {
+                    native_mint_account.lamports = existing_native_mint_account.lamports;
+                }
+            }
+            self.store_account(
+                &inline_spl_token_v2_0::native_mint::id(),
+                &native_mint_account,
+            );
+        }
+    }
+
     fn fix_recent_blockhashes_sysvar_delay(&self) -> bool {
         let activation_slot = match self.operating_mode() {
             OperatingMode::Development => 0,