按账户汇总分配登记权益并保持显式模拟舍入合同

crates/fidc-core/src/corporate_book.rs

@@ -683,6 +683,7 @@ mod tests {
             payable_date: None,
             record_date: date().pred_opt(),
             share_effective_date: None,
+            share_rounding_rule: None,
             share_cash: 0.,
             share_bonus: 0.,
             share_gift: 0.,

crates/fidc-core/src/data.rs

@@ -272,6 +272,8 @@ pub struct CorporateAction {
     pub record_date: Option<NaiveDate>,
     #[serde(default, with = "optional_date_format")]
     pub share_effective_date: Option<NaiveDate>,
+    #[serde(default)]
+    pub share_rounding_rule: Option<String>,
     pub share_cash: f64,
     pub share_bonus: f64,
     pub share_gift: f64,
@@ -5547,6 +5549,7 @@ mod tests {
                 payable_date: Some(date),
                 record_date: date.pred_opt(),
                 share_effective_date: None,
+                share_rounding_rule: None,
                 share_cash: 0.1,
                 share_bonus: 0.02,
                 share_gift: 0.03,

crates/fidc-core/src/platform_expr_strategy.rs

@@ -26576,6 +26576,7 @@ mod tests {
                 payable_date: Some(date),
                 record_date: date.pred_opt(),
                 share_effective_date: Some(date),
+                share_rounding_rule: None,
                 share_cash: 0.2,
                 share_bonus: 0.1,
                 share_gift: 0.0,

crates/fidc-core/src/portfolio.rs

@@ -912,16 +912,35 @@ impl PortfolioState {
             .map_err(|_| "corporate_action_quantity_overflow: share rate exceeds exact arithmetic domain")?;
         if rate <= Decimal::ZERO { return Err("corporate_action_share_rate_not_positive".into()); }
         let registered = self.registered_lots(record_date, &action.symbol)?;
+        if action.share_rounding_rule.as_deref().is_some_and(|rule| rule != "aggregate_half_up") {
+            return Err("corporate_action_share_rounding_rule_unsupported".into());
+        }
+        let ideal = registered.iter().try_fold(Decimal::ZERO, |total, lot| {
+            Decimal::from(lot.quantity).checked_mul(rate).and_then(|quantity| total.checked_add(quantity))
+                .ok_or("corporate_action_quantity_overflow: registered entitlement")
+        })?;
+        let settled = if ideal.fract() == Decimal::ZERO { ideal }
+            else if action.share_rounding_rule.as_deref() == Some("aggregate_half_up") {
+                ideal.round_dp_with_strategy(0, RoundingStrategy::MidpointAwayFromZero)
+            } else { return Err("corporate_action_fractional_share_settlement_evidence_required".into()); };
+        let total = settled.to_u32().ok_or("corporate_action_quantity_overflow: registered entitlement")?;
+        let mut allocated = Vec::new();
+        let mut floor_total = 0u32;
+        for (index, lot) in registered.iter().enumerate() {
+            let value = Decimal::from(lot.quantity).checked_mul(rate).ok_or("registered share entitlement overflow")?;
+            let floor = value.trunc().to_u32().ok_or("registered share entitlement overflow")?;
+            floor_total = floor_total.checked_add(floor).ok_or("registered share entitlement overflow")?;
+            allocated.push((index, floor, value.fract()));
+        }
+        let remainder = total.checked_sub(floor_total).ok_or("registered share allocation exceeds total")? as usize;
+        if remainder > allocated.len() { return Err("registered share allocation remainder invalid".into()); }
+        allocated.sort_by(|a,b| b.2.cmp(&a.2).then_with(|| a.0.cmp(&b.0)));
+        for (_, quantity, _) in allocated.iter_mut().take(remainder) { *quantity += 1; }
+        allocated.sort_by_key(|entry| entry.0);
         let mut claims = Vec::new();
-        let mut total = 0u32;
-        for lot in registered {
-            let quantity = Decimal::from(lot.quantity).checked_mul(rate).ok_or("corporate_action_quantity_overflow: registered entitlement")?;
-            if quantity.fract() != Decimal::ZERO {
-                return Err("corporate_action_fractional_share_settlement_evidence_required".into());
-            }
-            let quantity = quantity.to_u32().ok_or("corporate_action_quantity_overflow: registered entitlement")?;
+        for ((index, quantity, _), lot) in allocated.into_iter().zip(registered) {
+            let _ = index;
             if quantity == 0 { continue; }
-            total = total.checked_add(quantity).ok_or("registered share entitlement overflow")?;
             claims.push(ShareReceivable { ex_date: action.date, record_date, effective_date,
                 quantity, holding_origin_date: lot.origin.acquired_date });
         }

crates/fidc-core/tests/automatic_trade_protection.rs

@@ -160,6 +160,7 @@ fn observed_manual_trades_then_split_keep_real_fill_protection_and_lock_dates()
         payable_date: None,
         record_date: Some(d(14)),
         share_effective_date: Some(d(15)),
+        share_rounding_rule: None,
         share_cash: 0.,
         share_bonus: 1.,
         share_gift: 0.,

crates/fidc-core/tests/corporate_actions.rs

@@ -269,6 +269,7 @@ fn successor_conversion_depletes_older_source_lots_before_newer_successor_buys()
             payable_date: None,
             record_date: Some(dates[1]),
             share_effective_date: None,
+            share_rounding_rule: None,
             share_cash: 0.,
             share_bonus: 0.,
             share_gift: 0.,
@@ -524,6 +525,7 @@ fn engine_reinvests_dividend_receivable_in_round_lots() {
             payable_date: Some(payable_date),
             record_date: Some(buy_date),
             share_effective_date: None,
+            share_rounding_rule: None,
             share_cash: 1.05,
             share_bonus: 0.0,
             share_gift: 0.0,
@@ -609,6 +611,7 @@ fn engine_settles_same_day_dividend_after_split_for_aiquant_semantics() {
             payable_date: Some(ex_date),
             record_date: Some(buy_date),
             share_effective_date: Some(ex_date),
+            share_rounding_rule: None,
             share_cash: 1.05,
             share_bonus: 0.2,
             share_gift: 0.0,

crates/fidc-core/tests/delisting.rs

@@ -532,6 +532,7 @@ fn engine_applies_successor_conversion_before_unresolved_delisting_audit() {
             payable_date: None,
             record_date: Some(date1),
             share_effective_date: None,
+            share_rounding_rule: None,
             share_cash: 0.0,
             share_bonus: 0.0,
             share_gift: 0.0,

crates/fidc-core/tests/dividend_reinvestment_contract.rs

@@ -94,6 +94,7 @@ fn data() -> DataSet {
             payable_date: Some(day(14)),
             record_date: Some(day(11)),
             share_effective_date: None,
+            share_rounding_rule: None,
             share_cash: 1.05,
             share_bonus: 0.,
             share_gift: 0.,

crates/fidc-core/tests/manual_corporate_observation.rs

@@ -121,7 +121,8 @@ fn data_with_successor_metadata(action: Action, include_successor: bool) -> Data
             symbol: "000001.SZ".into(),
             payable_date: Some(date(14)),
             record_date: Some(date(11)),
-            share_effective_date: None,
+            share_effective_date: Some(date(14)),
+            share_rounding_rule: Some("aggregate_half_up".into()),
             share_cash: if matches!(action, Action::Dividend) {
                 1.
             } else {