Fix: bug(facilitator-sdk): facilitatorFee 校验仅支持 hex，导致动态 fee 流程失败 (#203)

* Fix: bug(facilitator-sdk): facilitatorFee 校验仅支持 hex，导致动态 fee 流程失败

* Apply changes from Holon

---------

Co-authored-by: holonbot[bot] <250454749+holonbot[bot]@users.noreply.github.com>

Author: holonbot[bot]

typescript/packages/facilitator-sdk/src/index.ts

@@ -50,6 +50,7 @@ export {
   isValidHex,
   isValid32ByteHex,
   isValid256BitHex,
+  isValidFacilitatorFee,
   validateSettlementRouter,
   validateSettlementExtra,
   validateNetwork,

typescript/packages/facilitator-sdk/src/validation.ts

@@ -35,6 +35,55 @@ export function isValid256BitHex(hex: string): boolean {
   return /^0x[a-fA-F0-9]{1,64}$/.test(hex);
 }
 
+/**
+ * Check if a string is a valid facilitator fee amount.
+ * Accepts both decimal (atomic units) and hex formats for compatibility.
+ * Ensures the value is non-negative and fits within uint256.
+ *
+ * @param fee - The fee amount to validate (decimal or hex string)
+ * @returns true if the fee is valid, false otherwise
+ *
+ * @example
+ * ```typescript
+ * isValidFacilitatorFee("10000")        // true - decimal
+ * isValidFacilitatorFee("0x2710")      // true - hex (10000)
+ * isValidFacilitatorFee("0x0")         // true - zero
+ * isValidFacilitatorFee("-100")        // false - negative
+ * isValidFacilitatorFee("abc")         // false - non-numeric
+ * isValidFacilitatorFee("0xXYZ")       // false - invalid hex
+ * ```
+ */
+export function isValidFacilitatorFee(fee: string): boolean {
+  if (!fee || typeof fee !== "string") {
+    return false;
+  }
+
+  // Check if it's a hex string (0x prefix)
+  if (fee.startsWith("0x") || fee.startsWith("0X")) {
+    // Must be valid hex with 1-64 hex digits (uint256 max)
+    return /^0[xX][a-fA-F0-9]{1,64}$/.test(fee);
+  }
+
+  // Check if it's a decimal string (atomic units)
+  // Must be one or more digits, no sign or decimal point
+  if (!/^\d+$/.test(fee)) {
+    return false;
+  }
+
+  // Ensure it fits within uint256 (max value is 2^256 - 1)
+  try {
+    const value = BigInt(fee);
+    const MAX_UINT256 = BigInt(
+      "115792089237316195423570985008687907853269984665640564039457584007913129639935",
+    );
+
+    // Value must be non-negative and must not exceed the uint256 maximum
+    return value >= 0n && value <= MAX_UINT256;
+  } catch {
+    return false;
+  }
+}
+
 /**
  * Validate SettlementRouter address against allowed list
  */
@@ -105,8 +154,10 @@ export function validateSettlementExtra(extra: unknown): SettlementExtraCore {
   if (!e.facilitatorFee || typeof e.facilitatorFee !== "string") {
     throw new FacilitatorValidationError("Missing or invalid facilitatorFee");
   }
-  if (!isValid256BitHex(e.facilitatorFee)) {
-    throw new FacilitatorValidationError("Facilitator fee must be a valid hex number");
+  if (!isValidFacilitatorFee(e.facilitatorFee)) {
+    throw new FacilitatorValidationError(
+      "Facilitator fee must be a valid number (decimal atomic units or hex format)",
+    );
   }
 
   if (!e.hook || typeof e.hook !== "string") {

typescript/packages/facilitator-sdk/test/validation.test.ts

@@ -8,6 +8,7 @@ import {
   isValidHex,
   isValid32ByteHex,
   isValid256BitHex,
+  isValidFacilitatorFee,
   validateSettlementRouter,
   validateSettlementExtra,
   validateNetwork,
@@ -81,6 +82,110 @@ describe("validation utilities", () => {
     });
   });
 
+  describe("isValidFacilitatorFee", () => {
+    describe("decimal format (atomic units)", () => {
+      it("should return true for valid decimal strings", () => {
+        expect(isValidFacilitatorFee("0")).toBe(true);
+        expect(isValidFacilitatorFee("10000")).toBe(true);
+        expect(isValidFacilitatorFee("1000000")).toBe(true); // 1 USDC (6 decimals)
+        expect(isValidFacilitatorFee("1000000000000000000")).toBe(true); // 1 ETH (18 decimals)
+        expect(isValidFacilitatorFee("1")).toBe(true);
+        expect(isValidFacilitatorFee("123456789")).toBe(true);
+      });
+
+      it("should return false for non-numeric decimal strings", () => {
+        expect(isValidFacilitatorFee("abc")).toBe(false);
+        expect(isValidFacilitatorFee("100abc")).toBe(false);
+        expect(isValidFacilitatorFee("12.34")).toBe(false); // decimal point not allowed
+        expect(isValidFacilitatorFee("-100")).toBe(false); // negative sign not allowed
+        expect(isValidFacilitatorFee("+100")).toBe(false); // plus sign not allowed
+      });
+
+      it("should return false for decimal values that exceed uint256", () => {
+        // A value with more than 78 digits exceeds uint256 max (2^256-1 ≈ 1.16e77)
+        const tooLarge = "1" + "0".repeat(78);
+        expect(isValidFacilitatorFee(tooLarge)).toBe(false);
+
+        // Test with an even larger number
+        const wayTooLarge = "9".repeat(100);
+        expect(isValidFacilitatorFee(wayTooLarge)).toBe(false);
+      });
+
+      it("should accept values within uint256 range", () => {
+        // Max uint256 is approximately 1.16e77, so 77-78 digits is the boundary
+        expect(isValidFacilitatorFee("1" + "0".repeat(76))).toBe(true);
+        expect(isValidFacilitatorFee("115792089237316195423570985008687907853269984665640564039457584007913129639935")).toBe(true); // 2^256 - 1
+      });
+    });
+
+    describe("hex format", () => {
+      it("should return true for valid hex strings", () => {
+        expect(isValidFacilitatorFee("0x0")).toBe(true);
+        expect(isValidFacilitatorFee("0x1")).toBe(true);
+        expect(isValidFacilitatorFee("0x2710")).toBe(true); // 10000 in decimal
+        expect(isValidFacilitatorFee("0x186A0")).toBe(true); // 100000 in decimal (0.1 USDC)
+        expect(isValidFacilitatorFee("0x" + "FF".repeat(32))).toBe(true);
+        expect(isValidFacilitatorFee("0xFF")).toBe(true);
+        expect(isValidFacilitatorFee("0xabcdef")).toBe(true);
+        expect(isValidFacilitatorFee("0xABCDEF")).toBe(true);
+      });
+
+      it("should return false for invalid hex strings", () => {
+        expect(isValidFacilitatorFee("0x" + "FF".repeat(33))).toBe(false); // > 256 bits
+        expect(isValidFacilitatorFee("0xGG")).toBe(false);
+        expect(isValidFacilitatorFee("0x")).toBe(false); // empty hex
+      });
+
+      it("should accept odd-length hex strings", () => {
+        expect(isValidFacilitatorFee("0x123")).toBe(true); // odd-length hex is valid numeric input
+        expect(isValidFacilitatorFee("0x1")).toBe(true); // single digit
+        expect(isValidFacilitatorFee("0xFFF")).toBe(true); // 4095
+      });
+    });
+
+    describe("edge cases", () => {
+      it("should return false for empty string", () => {
+        expect(isValidFacilitatorFee("")).toBe(false);
+      });
+
+      it("should return false for non-string types", () => {
+        expect(isValidFacilitatorFee(null as unknown as string)).toBe(false);
+        expect(isValidFacilitatorFee(undefined as unknown as string)).toBe(false);
+        expect(isValidFacilitatorFee(10000 as unknown as string)).toBe(false);
+      });
+
+      it("should handle uppercase 0X prefix", () => {
+        expect(isValidFacilitatorFee("0X2710")).toBe(true);
+        expect(isValidFacilitatorFee("0XABCDEF")).toBe(true);
+      });
+
+      it("should return false for malformed inputs", () => {
+        expect(isValidFacilitatorFee("10000 ")).toBe(false); // trailing space
+        expect(isValidFacilitatorFee(" 10000")).toBe(false); // leading space
+        expect(isValidFacilitatorFee("0x 2710")).toBe(false); // space after prefix
+        expect(isValidFacilitatorFee("0x2710 ")).toBe(false); // trailing space
+      });
+    });
+
+    describe("cross-format equivalence", () => {
+      it("should accept equivalent values in both formats", () => {
+        // 10000 in decimal and hex
+        expect(isValidFacilitatorFee("10000")).toBe(true);
+        expect(isValidFacilitatorFee("0x2710")).toBe(true);
+
+        // 0 in both formats
+        expect(isValidFacilitatorFee("0")).toBe(true);
+        expect(isValidFacilitatorFee("0x0")).toBe(true);
+
+        // Large number in both formats
+        const largeDecimal = "1000000000000000000"; // 1e18
+        const largeHex = "0xde0b6b3a7640000"; // Same value in hex
+        expect(isValidFacilitatorFee(largeDecimal)).toBe(true);
+        expect(isValidFacilitatorFee(largeHex)).toBe(true);
+      });
+    });
+  });
+
   describe("validateSettlementRouter", () => {
     it("should validate valid router address", () => {
       const result = validateSettlementRouter(
@@ -132,12 +237,26 @@ describe("validation utilities", () => {
   });
 
   describe("validateSettlementExtra", () => {
-    it("should validate valid settlement extra", () => {
+    it("should validate valid settlement extra with hex facilitatorFee", () => {
       const extra = {
         settlementRouter: MOCK_ADDRESSES.settlementRouter,
         salt: MOCK_VALUES.salt,
         payTo: MOCK_ADDRESSES.merchant,
-        facilitatorFee: MOCK_VALUES.facilitatorFee,
+        facilitatorFee: MOCK_VALUES.facilitatorFee, // hex format
+        hook: MOCK_ADDRESSES.hook,
+        hookData: MOCK_VALUES.hookData,
+      };
+
+      const result = validateSettlementExtra(extra);
+      expect(result).toEqual(extra);
+    });
+
+    it("should validate valid settlement extra with decimal facilitatorFee", () => {
+      const extra = {
+        settlementRouter: MOCK_ADDRESSES.settlementRouter,
+        salt: MOCK_VALUES.salt,
+        payTo: MOCK_ADDRESSES.merchant,
+        facilitatorFee: "100000", // decimal format (same as 0x186A0)
         hook: MOCK_ADDRESSES.hook,
         hookData: MOCK_VALUES.hookData,
       };
@@ -146,6 +265,34 @@ describe("validation utilities", () => {
       expect(result).toEqual(extra);
     });
 
+    it("should validate facilitatorFee as decimal zero", () => {
+      const extra = {
+        settlementRouter: MOCK_ADDRESSES.settlementRouter,
+        salt: MOCK_VALUES.salt,
+        payTo: MOCK_ADDRESSES.merchant,
+        facilitatorFee: "0", // decimal zero
+        hook: MOCK_ADDRESSES.hook,
+        hookData: MOCK_VALUES.hookData,
+      };
+
+      const result = validateSettlementExtra(extra);
+      expect(result.facilitatorFee).toBe("0");
+    });
+
+    it("should validate facilitatorFee as hex zero", () => {
+      const extra = {
+        settlementRouter: MOCK_ADDRESSES.settlementRouter,
+        salt: MOCK_VALUES.salt,
+        payTo: MOCK_ADDRESSES.merchant,
+        facilitatorFee: "0x0", // hex zero
+        hook: MOCK_ADDRESSES.hook,
+        hookData: MOCK_VALUES.hookData,
+      };
+
+      const result = validateSettlementExtra(extra);
+      expect(result.facilitatorFee).toBe("0x0");
+    });
+
     it("should throw for missing extra", () => {
       expect(() => {
         validateSettlementExtra(null);
@@ -195,6 +342,51 @@ describe("validation utilities", () => {
         validateSettlementExtra(extra);
       }).toThrow(FacilitatorValidationError);
     });
+
+    it("should throw for invalid facilitatorFee (non-numeric)", () => {
+      const extra = {
+        settlementRouter: MOCK_ADDRESSES.settlementRouter,
+        salt: MOCK_VALUES.salt,
+        payTo: MOCK_ADDRESSES.merchant,
+        facilitatorFee: "invalid-fee",
+        hook: MOCK_ADDRESSES.hook,
+        hookData: MOCK_VALUES.hookData,
+      };
+
+      expect(() => {
+        validateSettlementExtra(extra);
+      }).toThrow(FacilitatorValidationError);
+    });
+
+    it("should throw for invalid facilitatorFee (negative)", () => {
+      const extra = {
+        settlementRouter: MOCK_ADDRESSES.settlementRouter,
+        salt: MOCK_VALUES.salt,
+        payTo: MOCK_ADDRESSES.merchant,
+        facilitatorFee: "-10000",
+        hook: MOCK_ADDRESSES.hook,
+        hookData: MOCK_VALUES.hookData,
+      };
+
+      expect(() => {
+        validateSettlementExtra(extra);
+      }).toThrow(FacilitatorValidationError);
+    });
+
+    it("should throw for invalid facilitatorFee (malformed hex)", () => {
+      const extra = {
+        settlementRouter: MOCK_ADDRESSES.settlementRouter,
+        salt: MOCK_VALUES.salt,
+        payTo: MOCK_ADDRESSES.merchant,
+        facilitatorFee: "0xXYZ123",
+        hook: MOCK_ADDRESSES.hook,
+        hookData: MOCK_VALUES.hookData,
+      };
+
+      expect(() => {
+        validateSettlementExtra(extra);
+      }).toThrow(FacilitatorValidationError);
+    });
   });
 
   describe("validateNetwork", () => {