perf: batch stat counter writes to reduce storage write count

contracts/invoice_liquidity/src/access.rs

@@ -1,5 +1,6 @@
 use crate::errors::ContractError;
-use crate::invoice::{get_invoice_funders, invoice_exists, load_invoice, StorageKey};
+use crate::invoice::{invoice_exists, load_invoice};
+use crate::storage::{get_invoice_funders, DataKey as StorageKey};
 use soroban_sdk::{Address, Env};
 
 #[derive(Clone, Debug, Eq, PartialEq)]

contracts/invoice_liquidity/src/errors.rs

@@ -1,46 +1,39 @@
 use soroban_sdk::contracterror;
 
 #[contracterror]
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+#[repr(u32)]
 pub enum ContractError {
-    InvoiceNotFound = 1,
-    AlreadyFunded = 2,
-    AlreadyPaid = 3,
-    NotFunded = 4,
-    Unauthorized = 5,
-    InvalidAmount = 6,
-    InvalidDiscountRate = 7,
-    InvalidDueDate = 8,
-    InvoiceDefaulted = 9,
-    NothingToClaim = 10,
-    NotYetDefaulted = 11,
-    OverfundingRejected = 12,
-    InvoiceExpired = 13,
-    BatchTooLarge = 14,
-    AlreadyCancelled = 15,
-    AlreadyInitialized = 16,
-    // ── Issue #36: appeal_default ──────────────────────────────────
-    /// Payer attempted to appeal an invoice that is already in Appealed state.
-    AlreadyAppealed = 17,
-    /// Appeal window has closed; appeal can no longer be submitted.
-    AppealWindowClosed = 18,
-    /// Action requires the invoice to be in Defaulted state.
-    NotDefaulted = 19,
-    // ── Issue #34: LP priority queue ──────────────────────────────
-    /// LP has already joined the fund queue for this invoice.
-    AlreadyInQueue = 20,
-    /// fund_invoice rejected because a different LP was selected by the priority queue.
-    NotApprovedFunder = 21,
-    /// Invoice is in Appealed state and cannot be acted upon yet.
-    InvoiceAppealed = 22,
-    AlreadyDisputed = 23,
-    NotDisputed = 24,
-    InvoiceDisputed = 25,
-    ContractPaused = 26,
-    DueDateTooSoon = 27,
-    DueDateTooFar = 28,
-    SelfInvoice = 29,
-    OverpaymentRejected = 30,
-    /// Issue #28: payer's reputation is below the configured minimum threshold.
-    PayerReputationTooLow = 31,
+    Unauthorized = 1,
+    AlreadyInitialized = 2,
+    InvalidAmount = 3,
+    InvalidDiscountRate = 4,
+    InvalidDueDate = 5,
+    InvoiceNotFound = 6,
+    AlreadyPaid = 7,
+    AlreadyFunded = 8,
+    NotYetDefaulted = 9,
+    InvoiceDefaulted = 10,
+    OverfundingRejected = 11,
+    OverpaymentRejected = 12,
+    ArithmeticOverflow = 13,
+    NothingToClaim = 14,
+    SelfInvoice = 15,
+    InvoiceExpired = 16,
+    BatchTooLarge = 17,
+    AlreadyCancelled = 18,
+    ContractPaused = 19,
+    DueDateTooSoon = 20,
+    DueDateTooFar = 21,
+    AlreadyInQueue = 22,
+    NotApprovedFunder = 23,
+    PayerReputationTooLow = 24,
+    InvoiceAppealed = 25,
+    AlreadyAppealed = 26,
+    AppealWindowClosed = 27,
+    NotDefaulted = 28,
+    AlreadyDisputed = 29,
+    NotDisputed = 30,
+    InvoiceDisputed = 31,
+    NotFunded = 32,
 }