implement perp purge position

programs/mango-v4/src/accounts_ix/mod.rs

@@ -45,6 +45,7 @@ pub use perp_liq_force_cancel_orders::*;
 pub use perp_liq_negative_pnl_or_bankruptcy::*;
 pub use perp_place_order::*;
 pub use perp_prune_orders::*;
+pub use perp_purge_position::*;
 pub use perp_settle_fees::*;
 pub use perp_settle_pnl::*;
 pub use perp_update_funding::*;
@@ -127,6 +128,7 @@ mod perp_liq_force_cancel_orders;
 mod perp_liq_negative_pnl_or_bankruptcy;
 mod perp_place_order;
 mod perp_prune_orders;
+mod perp_purge_position;
 mod perp_settle_fees;
 mod perp_settle_pnl;
 mod perp_update_funding;

programs/mango-v4/src/accounts_ix/perp_purge_position.rs

@@ -0,0 +1,27 @@
+use anchor_lang::prelude::*;
+
+use crate::error::*;
+use crate::state::*;
+
+#[derive(Accounts)]
+pub struct PerpPurgePosition<'info> {
+    #[account()]
+    pub group: AccountLoader<'info, Group>,
+
+    #[account(
+        mut,
+        has_one = group,
+        // owner is not checked on purpose
+    )]
+    pub account: AccountLoader<'info, MangoAccountFixed>,
+
+    #[account(has_one = group)]
+    pub perp_market: AccountLoader<'info, PerpMarket>,
+
+    #[account(mut, has_one = group)]
+    pub settle_bank: AccountLoader<'info, Bank>,
+
+    /// CHECK: Oracle can have different account types
+    #[account(address = settle_bank.load()?.oracle)]
+    pub settle_oracle: UncheckedAccount<'info>,
+}

programs/mango-v4/src/instructions/mod.rs

@@ -35,6 +35,7 @@ pub use perp_liq_force_cancel_orders::*;
 pub use perp_liq_negative_pnl_or_bankruptcy::*;
 pub use perp_place_order::*;
 pub use perp_prune_orders::*;
+pub use perp_purge_position::*;
 pub use perp_settle_fees::*;
 pub use perp_settle_pnl::*;
 pub use perp_update_funding::*;
@@ -108,6 +109,7 @@ mod perp_liq_force_cancel_orders;
 mod perp_liq_negative_pnl_or_bankruptcy;
 mod perp_place_order;
 mod perp_prune_orders;
+mod perp_purge_position;
 mod perp_settle_fees;
 mod perp_settle_pnl;
 mod perp_update_funding;

programs/mango-v4/src/instructions/perp_purge_position.rs

@@ -0,0 +1,93 @@
+use anchor_lang::prelude::*;
+use fixed::types::I80F48;
+
+use crate::accounts_ix::*;
+use crate::error::*;
+use crate::logs::emit_perp_balances;
+use crate::logs::emit_stack;
+use crate::logs::TokenBalanceLog;
+use crate::require_msg;
+use crate::state::*;
+
+pub fn perp_purge_position(ctx: Context<PerpPurgePosition>) -> Result<()> {
+    let perp_market = ctx.accounts.perp_market.load()?;
+    // only allow purging positions when market is in force-close
+    require!(perp_market.is_force_close(), MangoError::SomeError);
+
+    let mut settle_bank = ctx.accounts.settle_bank.load_mut()?;
+    // Verify that the bank is the quote currency bank
+    require!(
+        settle_bank.token_index == perp_market.settle_token_index,
+        MangoError::InvalidBank
+    );
+
+    let mut account = ctx.accounts.account.load_full_mut()?;
+    let perp_position = account.perp_position_mut(perp_market.perp_market_index)?;
+
+    // Base position needs to be zero'd out already and all orders closed
+    require_msg!(
+        perp_position.base_position_lots() == 0,
+        "perp position still has base lots"
+    );
+    require_msg!(
+        perp_position.bids_base_lots == 0 && perp_position.asks_base_lots == 0,
+        "perp position still has open orders"
+    );
+    require_msg!(
+        perp_position.taker_base_lots == 0 && perp_position.taker_quote_lots == 0,
+        "perp position still has events on event queue"
+    );
+
+    // Flush funding so that all remaining quote position is accounted for
+    perp_position.settle_funding(&perp_market);
+    let settlement = -perp_position.quote_position_native();
+
+    // only if there's negative pnl we settle directly with bank
+    // note: the positive pnl case is not implemented
+    if settlement != 0 {
+        require_msg!(
+            settlement > I80F48::ZERO,
+            "can only purge negative quote positions"
+        );
+
+        // Set perp quote to 0
+        perp_position.record_settle(settlement, &perp_market);
+        emit_perp_balances(
+            ctx.accounts.group.key(),
+            ctx.accounts.account.key(),
+            perp_position,
+            &perp_market,
+        );
+
+        // Update the accounts' perp_spot_transfer statistics.
+        let settlement_i64 = settlement.round_to_zero().to_num::<i64>();
+        perp_position.perp_spot_transfers += settlement_i64;
+        drop(perp_position);
+        account.fixed.perp_spot_transfers += settlement_i64;
+
+        // Settle quote token balance
+        let token_position = account
+            .token_position_mut(perp_market.settle_token_index)?
+            .0;
+        let now_ts: u64 = Clock::get()?.unix_timestamp.try_into().unwrap();
+        settle_bank.withdraw_without_fee(token_position, settlement, now_ts)?;
+
+        emit_stack(TokenBalanceLog {
+            mango_group: ctx.accounts.group.key(),
+            mango_account: ctx.accounts.account.key(),
+            token_index: perp_market.settle_token_index,
+            indexed_position: token_position.indexed_position.to_bits(),
+            deposit_index: settle_bank.deposit_index.to_bits(),
+            borrow_index: settle_bank.borrow_index.to_bits(),
+        });
+    }
+
+    // clean up perp position to free up oracles for users and allow closing market
+    account.deactivate_perp_position_and_log(
+        perp_market.perp_market_index,
+        perp_market.settle_token_index,
+        ctx.accounts.account.key(),
+    )?;
+
+    Ok(())
+}

programs/mango-v4/src/lib.rs

@@ -1015,6 +1015,12 @@ pub mod mango_v4 {
         Ok(())
     }
 
+    pub fn perp_purge_position(ctx: Context<PerpPurgePosition>) -> Result<()> {
+        #[cfg(feature = "enable-gpl")]
+        instructions::perp_purge_position(ctx)?;
+        Ok(())
+    }
+
     #[allow(clippy::too_many_arguments)]
     pub fn perp_place_order(
         ctx: Context<PerpPlaceOrder>,