lang: adjust realloc implementation to safeguard max increase and i…

…dempotency (#1986)

.github/workflows/tests.yaml

@@ -360,6 +360,8 @@ jobs:
             path: tests/escrow
           - cmd: cd tests/pyth && anchor test --skip-lint && npx tsc --noEmit
             path: tests/pyth
+          - cmd: cd tests/realloc && anchor test --skip-lint && npx tsc --noEmit
+            path: tests/realloc
           - cmd: cd tests/system-accounts && anchor test --skip-lint
             path: tests/system-accounts
           - cmd: cd tests/misc && anchor test --skip-lint && npx tsc --noEmit

CHANGELOG.md

@@ -12,9 +12,9 @@ The minor version will be incremented upon a breaking change and the patch versi
 
 ### Features
 
+* lang: Add `realloc`, `realloc::payer`, and `realloc::zero` as a new constraint group for program accounts ([#1986](https://github.com/coral-xyz/anchor/pull/1986)).
 * lang: Add `PartialEq` and `Eq` for `anchor_lang::Error` ([#1544](https://github.com/coral-xyz/anchor/pull/1544)).
-* cli: Add `--skip-build` to `anchor publish` ([#1786](https://github.
-com/project-serum/anchor/pull/1841)).
+* cli: Add `--skip-build` to `anchor publish` ([#1786](https://github.com/coral-xyz/anchor/pull/1841)).
 * cli: Add `--program-keypair` to `anchor deploy` ([#1786](https://github.com/coral-xyz/anchor/pull/1786)).
 * cli: Add compilation optimizations to cli template ([#1807](https://github.com/coral-xyz/anchor/pull/1807)).
 * cli: `build` now adds docs to idl. This can be turned off with `--no-docs` ([#1561](https://github.com/coral-xyz/anchor/pull/1561)).
@@ -41,6 +41,7 @@ com/project-serum/anchor/pull/1841)).
 * ts: Change `BROWSER` env variable to `ANCHOR_BROWSER` ([#1233](https://github.com/coral-xyz/anchor/pull/1233)).
 * ts: Add transaction signature to `EventCallback` parameters ([#1851](https://github.com/coral-xyz/anchor/pull/1851)).
 * ts: Change `EventParser#parseLogs` implementation to be a generator instead of callback function ([#2018](https://github.com/coral-xyz/anchor/pull/2018)).
+* lang: Adds a new `&mut reallocs: BTreeSet<Pubkey>` argument to `Accounts::try_accounts` ([#1986](https://github.com/coral-xyz/anchor/pull/1986)).
 
 ## [0.24.2] - 2022-04-13
 

lang/derive/accounts/src/lib.rs

@@ -44,6 +44,7 @@ use syn::parse_macro_input;
 ///
 /// - [Normal Constraints](#normal-constraints)
 /// - [SPL Constraints](#spl-constraints)
+///
 /// # Normal Constraints
 /// <table>
 ///     <thead>
@@ -418,6 +419,48 @@ use syn::parse_macro_input;
 ///                 </code></pre>
 ///             </td>
 ///         </tr>
+///         <tr>
+///             <td>
+///                 <code>#[account(realloc = &lt;space&gt;, realloc::payer = &lt;target&gt;, realloc::zero = &lt;bool&gt;)]</code>
+///             </td>
+///             <td>
+///                 Used to <a href="https://docs.rs/solana-program/latest/solana_program/account_info/struct.AccountInfo.html#method.realloc" target = "_blank" rel = "noopener noreferrer">realloc</a>
+///                 program account space at the beginning of an instruction.
+///                 <br><br>
+///                 The account must be marked as <code>mut</code> and applied to either <code>Account</code> or <code>AccountLoader</code> types.
+///                 <br><br>
+///                 If the change in account data length is additive, lamports will be transferred from the <code>realloc::payer</code> into the
+///                 program account in order to maintain rent exemption. Likewise, if the change is subtractive, lamports will be transferred from
+///                 the program account back into the <code>realloc::payer</code>.
+///                 <br><br>
+///                 The <code>realloc::zero</code> constraint is required in order to determine whether the new memory should be zero initialized after
+///                 reallocation. Please read the documentation on the <code>AccountInfo::realloc</code> function linked above to understand the
+///                 caveats regarding compute units when providing <code>true</code or <code>false</code> to this flag.
+///                 <br><br>
+///                 The manual use of `AccountInfo::realloc` is discouraged in favor of the `realloc` constraint group due to the lack of native runtime checks
+///                 to prevent reallocation over the `MAX_PERMITTED_DATA_INCREASE` limit (which can unintentionally cause account data overwrite other accounts).
+///                 The constraint group also ensure account reallocation idempotency but checking and restricting duplicate account reallocation within a single ix.
+///                 <br><br>
+///                 Example:
+///                 <pre>
+/// #[derive(Accounts)]
+/// pub struct Example {
+///     #[account(mut)]
+///     pub payer: Signer<'info>,
+///     #[account(
+///         mut,
+///         seeds = [b"example"],
+///         bump,
+///         realloc = 8 + std::mem::size_of::<MyType>() + 100,
+///         realloc::payer = payer,
+///         realloc::zero = false,
+///     )]
+///     pub acc: Account<'info, MyType>,
+///     pub system_program: Program<'info, System>,
+/// }
+///                 </pre>
+///             </td>
+///         </tr>
 ///     </tbody>
 /// </table>
 ///

lang/src/accounts/account.rs

@@ -10,7 +10,7 @@ use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
 use solana_program::system_program;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 use std::ops::{Deref, DerefMut};
 
@@ -321,6 +321,7 @@ where
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/account_info.rs

@@ -7,14 +7,15 @@ use crate::{Accounts, AccountsExit, Key, Result, ToAccountInfos, ToAccountMetas}
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 
 impl<'info> Accounts<'info> for AccountInfo<'info> {
     fn try_accounts(
         _program_id: &Pubkey,
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/account_loader.rs

@@ -11,7 +11,7 @@ use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
 use std::cell::{Ref, RefMut};
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 use std::io::Write;
 use std::marker::PhantomData;
@@ -221,6 +221,7 @@ impl<'info, T: ZeroCopy + Owner> Accounts<'info> for AccountLoader<'info, T> {
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/boxed.rs

@@ -17,7 +17,7 @@ use crate::{Accounts, AccountsClose, AccountsExit, Result, ToAccountInfos, ToAcc
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ops::Deref;
 
 impl<'info, T: Accounts<'info>> Accounts<'info> for Box<T> {
@@ -26,8 +26,9 @@ impl<'info, T: Accounts<'info>> Accounts<'info> for Box<T> {
         accounts: &mut &[AccountInfo<'info>],
         ix_data: &[u8],
         bumps: &mut BTreeMap<String, u8>,
+        reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
-        T::try_accounts(program_id, accounts, ix_data, bumps).map(Box::new)
+        T::try_accounts(program_id, accounts, ix_data, bumps, reallocs).map(Box::new)
     }
 }
 

lang/src/accounts/cpi_account.rs

@@ -53,6 +53,7 @@ where
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/cpi_state.rs

@@ -8,7 +8,7 @@ use crate::{
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ops::{Deref, DerefMut};
 
 /// Boxed container for the program state singleton, used when the state
@@ -72,6 +72,7 @@ where
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/loader.rs

@@ -9,7 +9,7 @@ use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
 use std::cell::{Ref, RefMut};
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 use std::io::Write;
 use std::marker::PhantomData;
@@ -163,6 +163,7 @@ impl<'info, T: ZeroCopy> Accounts<'info> for Loader<'info, T> {
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/program.rs

@@ -8,7 +8,7 @@ use solana_program::account_info::AccountInfo;
 use solana_program::bpf_loader_upgradeable::{self, UpgradeableLoaderState};
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 use std::marker::PhantomData;
 use std::ops::Deref;
@@ -147,6 +147,7 @@ where
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/program_account.rs

@@ -9,7 +9,7 @@ use crate::{
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ops::{Deref, DerefMut};
 
 /// Boxed container for a deserialized `account`. Use this to reference any
@@ -83,6 +83,7 @@ where
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/signer.rs

@@ -4,7 +4,7 @@ use crate::{Accounts, AccountsExit, Key, Result, ToAccountInfos, ToAccountMetas}
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ops::Deref;
 
 /// Type validating that the account signed the transaction. No other ownership
@@ -61,6 +61,7 @@ impl<'info> Accounts<'info> for Signer<'info> {
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/state.rs

@@ -9,7 +9,7 @@ use crate::{
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ops::{Deref, DerefMut};
 
 pub const PROGRAM_STATE_SEED: &str = "unversioned";
@@ -74,6 +74,7 @@ where
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/system_account.rs

@@ -6,7 +6,7 @@ use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
 use solana_program::system_program;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ops::Deref;
 
 /// Type validating that the account is owned by the system program
@@ -40,6 +40,7 @@ impl<'info> Accounts<'info> for SystemAccount<'info> {
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/sysvar.rs

@@ -5,7 +5,7 @@ use crate::{Accounts, AccountsExit, Key, Result, ToAccountInfos, ToAccountMetas}
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 use std::ops::{Deref, DerefMut};
 
@@ -71,6 +71,7 @@ impl<'info, T: solana_program::sysvar::Sysvar> Accounts<'info> for Sysvar<'info,
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/accounts/unchecked_account.rs

@@ -6,7 +6,7 @@ use crate::{Accounts, AccountsExit, Key, Result, ToAccountInfos, ToAccountMetas}
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ops::Deref;
 
 /// Explicit wrapper for AccountInfo types to emphasize
@@ -26,6 +26,7 @@ impl<'info> Accounts<'info> for UncheckedAccount<'info> {
         accounts: &mut &[AccountInfo<'info>],
         _ix_data: &[u8],
         _bumps: &mut BTreeMap<String, u8>,
+        _reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         if accounts.is_empty() {
             return Err(ErrorCode::AccountNotEnoughKeys.into());

lang/src/error.rs

@@ -178,6 +178,12 @@ pub enum ErrorCode {
     /// 3015 - The given public key does not match the required sysvar
     #[msg("The given public key does not match the required sysvar")]
     AccountSysvarMismatch,
+    /// 3016 - The account reallocation exceeds the MAX_PERMITTED_DATA_INCREASE limit
+    #[msg("The account reallocation exceeds the MAX_PERMITTED_DATA_INCREASE limit")]
+    AccountReallocExceedsLimit,
+    /// 3017 - The account was duplicated for more than one reallocation
+    #[msg("The account was duplicated for more than one reallocation")]
+    AccountDuplicateReallocs,
 
     // State.
     /// 4000 - The given state account does not have the correct address

lang/src/lib.rs

@@ -27,7 +27,7 @@ use bytemuck::{Pod, Zeroable};
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::io::Write;
 
 mod account_meta;
@@ -82,6 +82,7 @@ pub trait Accounts<'info>: ToAccountMetas + ToAccountInfos<'info> + Sized {
         accounts: &mut &[AccountInfo<'info>],
         ix_data: &[u8],
         bumps: &mut BTreeMap<String, u8>,
+        reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self>;
 }
 

lang/src/vec.rs

@@ -2,7 +2,7 @@ use crate::{Accounts, Result, ToAccountInfos, ToAccountMetas};
 use solana_program::account_info::AccountInfo;
 use solana_program::instruction::AccountMeta;
 use solana_program::pubkey::Pubkey;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 
 impl<'info, T: ToAccountInfos<'info>> ToAccountInfos<'info> for Vec<T> {
     fn to_account_infos(&self) -> Vec<AccountInfo<'info>> {
@@ -26,9 +26,11 @@ impl<'info, T: Accounts<'info>> Accounts<'info> for Vec<T> {
         accounts: &mut &[AccountInfo<'info>],
         ix_data: &[u8],
         bumps: &mut BTreeMap<String, u8>,
+        reallocs: &mut BTreeSet<Pubkey>,
     ) -> Result<Self> {
         let mut vec: Vec<T> = Vec::new();
-        T::try_accounts(program_id, accounts, ix_data, bumps).map(|item| vec.push(item))?;
+        T::try_accounts(program_id, accounts, ix_data, bumps, reallocs)
+            .map(|item| vec.push(item))?;
         Ok(vec)
     }
 }
@@ -78,9 +80,11 @@ mod tests {
             Epoch::default(),
         );
         let mut bumps = std::collections::BTreeMap::new();
+        let mut reallocs = std::collections::BTreeSet::new();
         let mut accounts = &[account1, account2][..];
         let parsed_accounts =
-            Vec::<Test>::try_accounts(&program_id, &mut accounts, &[], &mut bumps).unwrap();
+            Vec::<Test>::try_accounts(&program_id, &mut accounts, &[], &mut bumps, &mut reallocs)
+                .unwrap();
 
         assert_eq!(accounts.len(), parsed_accounts.len());
     }
@@ -90,7 +94,9 @@ mod tests {
     fn test_accounts_trait_for_vec_empty() {
         let program_id = Pubkey::default();
         let mut bumps = std::collections::BTreeMap::new();
+        let mut reallocs = std::collections::BTreeSet::new();
         let mut accounts = &[][..];
-        Vec::<Test>::try_accounts(&program_id, &mut accounts, &[], &mut bumps).unwrap();
+        Vec::<Test>::try_accounts(&program_id, &mut accounts, &[], &mut bumps, &mut reallocs)
+            .unwrap();
     }
 }