fix: improve error handling for forbidden countries list mismatch (#494)

* Update SelfBackendVerifier.ts

* Update constants.ts

* Update formatInputs.ts

* Update formatCallData.ts

common/src/constants/constants.ts

@@ -31,6 +31,12 @@ export const DEFAULT_MAJORITY = '18';
 export const hashAlgos = ['sha512', 'sha384', 'sha256', 'sha224', 'sha1'];
 export const saltLengths = [64, 48, 32];
 
+/**
+ * Maximum number of countries in the forbidden countries list.
+ * 
+ * IMPORTANT: This value must match in both backend and frontend SDK.
+ * Any mismatch will result in an INVALID_FORBIDDEN_COUNTRIES error.
+ */
 export const MAX_FORBIDDEN_COUNTRIES_LIST_LENGTH = 40;
 
 export const DEPLOYED_CIRCUITS_REGISTER = [

common/src/utils/circuits/formatInputs.ts

@@ -1,9 +1,39 @@
 import { MAX_FORBIDDEN_COUNTRIES_LIST_LENGTH } from "../../constants/constants";
+import { commonNames } from "../../constants/countries";
 
+/**
+ * Formats the list of country codes for use in verification circuits.
+ * Important: this list must exactly match the list in the backend.
+ * 
+ * @param countries Array of three-letter country codes
+ * @returns Formatted byte array representing country codes
+ * @throws Error if the maximum list length is exceeded or if country codes are invalid
+ */
 export function formatCountriesList(countries: string[]) {
+    // Check maximum list length
     if (countries.length > MAX_FORBIDDEN_COUNTRIES_LIST_LENGTH) {
         throw new Error(`Countries list must be inferior or equals to ${MAX_FORBIDDEN_COUNTRIES_LIST_LENGTH}`);
     }
+    
+    // Validate country codes
+    for (const country of countries) {
+        if (!country || country.length !== 3) {
+            throw new Error(`Invalid country code: "${country}". Country codes must be exactly 3 characters long.`);
+        }
+        
+        // Optional check for the country code existence in the list of valid codes
+        // This code can be uncommented if strict validation of country codes is needed
+        /*
+        const isValidCountry = Object.values(commonNames).some(
+            name => name === country || country in commonNames
+        );
+        
+        if (!isValidCountry) {
+            throw new Error(`Unknown country code: "${country}". Please use valid 3-letter ISO country codes.`);
+        }
+        */
+    }
+    
     const paddedCountries = countries.concat(Array(MAX_FORBIDDEN_COUNTRIES_LIST_LENGTH - countries.length).fill(''));
     const result = paddedCountries.flatMap((country) => {
         const chars = country
@@ -37,4 +67,4 @@ export function reverseCountryBytes(input: string): string {
     }
   
     return '0x' + reversedGroups.join('') + remainder;
-}
+}

common/src/utils/contracts/formatCallData.ts

@@ -46,6 +46,13 @@ export function packForbiddenCountriesList(forbiddenCountries: string[]): string
     const REQUIRED_CHUNKS = 4;
     const bytes: number[] = [];
     
+    // Validate all country codes (3 characters)
+    for (const country of forbiddenCountries) {
+        if (!country || country.length !== 3) {
+            throw new Error(`Invalid country code: "${country}". Country codes must be exactly 3 characters long.`);
+        }
+    }
+    
     // Convert countries to bytes
     for (const country of forbiddenCountries) {
         const countryCode = country.padEnd(3, ' ').slice(0, 3);

sdk/core/src/SelfBackendVerifier.ts

@@ -138,7 +138,13 @@ export class SelfBackendVerifier {
     let result: any;
     try {
       result = await this.verifyAllContract.verifyAll(timestamp, vcAndDiscloseHubProof, types);
-    } catch (error) {
+    } catch (error: any) {
+      let errorMessage = error instanceof Error ? error.message : 'Unknown error';
+      
+      if (error && typeof error === 'object' && error.message && error.message.includes('INVALID_FORBIDDEN_COUNTRIES')) {
+        errorMessage = 'The forbidden countries list in the backend does not match the list provided in the frontend SDK. Please ensure both lists are identical.';
+      }
+
       return {
         isValid: false,
         isValidDetails: {
@@ -157,7 +163,7 @@ export class SelfBackendVerifier {
             publicSignals: publicSignals,
           },
         },
-        error: error,
+        error: errorMessage,
       };
     }
 
@@ -224,10 +230,35 @@ export class SelfBackendVerifier {
     return this;
   }
 
+  /**
+   * Sets the list of countries to be excluded in the verification.
+   * This list must exactly match the list configured in the backend.
+   * 
+   * @param countries Array of 3-letter country codes to exclude
+   * @returns This instance for method chaining
+   * @throws Error if more than 40 countries are provided or if any country code is invalid
+   */
   excludeCountries(...countries: Country3LetterCode[]): this {
     if (countries.length > 40) {
       throw new Error('Number of excluded countries cannot exceed 40');
     }
+    
+    // Validate country codes
+    for (const country of countries) {
+      if (!country || country.length !== 3) {
+        throw new Error(`Invalid country code: "${country}". Country codes must be exactly 3 characters long.`);
+      }
+      
+      // Check if the country code exists in the list of valid codes (additional check)
+      const isValidCountry = Object.values(commonNames).some(
+        name => name === country || country in commonNames
+      );
+      
+      if (!isValidCountry) {
+        throw new Error(`Unknown country code: "${country}". Please use valid 3-letter ISO country codes.`);
+      }
+    }
+    
     this.excludedCountries = { enabled: true, value: countries };
     return this;
   }