perf: freeze rank expression presence

crates/fidc-core/src/platform_expr_strategy.rs

@@ -1121,6 +1121,7 @@ pub struct PlatformExprStrategy {
     prelude_declared_identifiers: BTreeSet<String>,
     stock_filter_quote_usage: StockFilterQuoteUsage,
     stock_filter_expr_present: bool,
+    rank_expr_present: bool,
     selection_quote_usage: StockFilterQuoteUsage,
     stock_rolling_requirements: StockRollingRequirements,
     stock_current_rolling_mean_required: bool,
@@ -1397,6 +1398,7 @@ impl PlatformExprStrategy {
         let prelude_declared_identifiers = Self::declared_prelude_identifiers(&config.prelude);
         let normalized_stock_filter_expr = Self::normalize_expr(&config.stock_filter_expr);
         let stock_filter_expr_present = !normalized_stock_filter_expr.is_empty();
+        let rank_expr_present = !config.rank_expr.trim().is_empty();
         let stock_filter_quote_usage =
             Self::stock_filter_quote_usage_for_expr(&normalized_stock_filter_expr);
         let selection_quote_usage =
@@ -1446,6 +1448,7 @@ impl PlatformExprStrategy {
             prelude_declared_identifiers,
             stock_filter_quote_usage,
             stock_filter_expr_present,
+            rank_expr_present,
             selection_quote_usage,
             stock_rolling_requirements,
             stock_current_rolling_mean_required,
@@ -9883,7 +9886,7 @@ impl PlatformExprStrategy {
         free_float_cap_bn: f64,
         stock: &StockExpressionState,
     ) -> Result<f64, BacktestError> {
-        if !self.config.rank_expr.trim().is_empty() {
+        if self.rank_expr_present {
             return match self.eval_float(ctx, &self.config.rank_expr, day, Some(stock), None) {
                 Ok(value) => Ok(value),
                 Err(error) if Self::is_missing_rolling_mean_error(&error) => Ok(f64::NAN),
@@ -9909,7 +9912,7 @@ impl PlatformExprStrategy {
     }
 
     fn rank_reuses_market_cap_order(&self) -> bool {
-        self.config.rank_expr.trim().is_empty()
+        !self.rank_expr_present
             && !self.config.rank_desc
             && matches!(self.config.rank_by.trim(), "market_cap" | "market_cap_bn")
     }