From c1a72bd13156095bc99e41b010047618c8450d5c Mon Sep 17 00:00:00 2001
From: Nexory <St4yl3r30@hotmail.de>
Date: Wed, 10 Jun 2026 11:26:30 +0200
Subject: [PATCH] fix(utils): allow integer prices written with trailing
 decimal zeros in formatPrice

`formatPrice` documents that "integer prices are always allowed regardless
of significant figures", and bypasses the 5-sig-fig truncation when the raw
input matches `/^-?\d+$/`. That check only runs on the raw input, so a price
that is integer-valued but written with a trailing decimal (e.g. "100001.0")
fails the regex, falls through to `toFixedTruncate` (which strips the ".0",
yielding "100001"), and is then truncated by the significant-figure step to
"100000".

Result: the same integer price produces different output depending on
formatting:

  formatPrice("100001",   0) === "100001"   // ok
  formatPrice("100001.0", 0) === "100000"   // wrong, off by 1
  formatPrice("123456.0", 0) === "123450"   // wrong
  formatPrice("-123456.0",0) === "-123450"  // wrong

A float-derived price (e.g. `n.toFixed(1)` -> "100001.0") therefore submits
an order at a different price than intended.

Re-check the integer-bypass after decimal truncation, so a value that became
an integer is treated the same as a raw integer. A value that truncated all
the way to zero is excluded so the existing "too small" RangeError still
fires.

Adds regression cases to tests/utils/format.test.ts. The full formatPrice
suite (including the reference-asset validation) passes; deno fmt and deno
lint are clean.
---
 src/utils/_format.ts       | 8 ++++++++
 tests/utils/format.test.ts | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/utils/_format.ts b/src/utils/_format.ts
index 1d088c7e..e382fe83 100644
--- a/src/utils/_format.ts
+++ b/src/utils/_format.ts
@@ -29,6 +29,14 @@ export function formatPrice(price: string | number, szDecimals: number, type: "p
   const maxDecimals = Math.max((type === "perp" ? 6 : 8) - szDecimals, 0);
   price = StringMath.toFixedTruncate(price, maxDecimals);
 
+  // Integer prices are always allowed, including values that become integers
+  // after decimal truncation (e.g. "100001.0" -> "100001"). Without this
+  // re-check the significant-figure step below would truncate them (-> "100000").
+  // A value that truncated all the way to zero is left for the zero check below.
+  if (/^-?\d+$/.test(price) && !/^-?0+$/.test(price)) {
+    return formatDecimalString(price);
+  }
+
   // Apply sig figs limit: max 5 significant figures
   price = StringMath.toPrecisionTruncate(price, 5);
 
diff --git a/tests/utils/format.test.ts b/tests/utils/format.test.ts
index 9a6d939b..975bc442 100644
--- a/tests/utils/format.test.ts
+++ b/tests/utils/format.test.ts
@@ -32,6 +32,14 @@ Deno.test("formatPrice", async (t) => {
       assertEquals(formatPrice("1234567", 0), "1234567");
     });
 
+    await t.step("integer value with trailing decimal zeros bypasses limit", () => {
+      assertEquals(formatPrice("100001.0", 0), "100001");
+      assertEquals(formatPrice("123456.0", 0), "123456");
+      assertEquals(formatPrice("100001.00", 0), "100001");
+      assertEquals(formatPrice("-123456.0", 0), "-123456");
+      assertEquals(formatPrice("100001.0", 0, "spot"), "100001");
+    });
+
     await t.step("truncates to 5 sig figs", () => {
       assertEquals(formatPrice("12345.6", 0), "12345");
       assertEquals(formatPrice("0.00123456", 0), "0.001234");