Method extract_variables_from_plan

graphlite/src/exec/executor.rs:9270–9282

Extract variable names from physical plan, falling back to first row if needed

(&self, node: &PhysicalNode, rows: &[Row])

    /// Extract variable names from physical plan, falling back to first row if needed
    fn extract_variables_from_plan(&self, node: &PhysicalNode, rows: &[Row]) -> Vec<String> {
        // Try to extract variables from the physical plan structure
        if let Some(variables) = self.extract_variables_from_node(node) {
            return variables;
        }

        // Fallback to extracting from the first row (original behavior)
        if let Some(first_row) = rows.first() {
            first_row.values.keys().cloned().collect()
        } else {
            Vec::new()
        }
    }

    /// Extract variables from a physical node (returns None if not a projection node)
    fn extract_variables_from_node(&self, node: &PhysicalNode) -> Option<Vec<String>> {