feat: ensure consistent decimals in Token checker (#4884)

### Description

- ensures actual (i.e. looking at onchain info, or chain metadata for
native warp routes) decimals are consistent and nonzero
- ensures any configured decimals are also consistent (but doesn't
require them to be present)
- cobbled together pretty quickly - not sure if there's a more elegant
way of having non-chain-specific checks

### Drive-by changes

<!--
Are there any minor or drive-by changes also included?
-->

### Related issues

<!--
- Fixes #[issue number here]
-->

### Backward compatibility

<!--
Are these changes backward compatible? Are there any infrastructure
implications, e.g. changes that would prohibit deploying older commits
using this infra tooling?

Yes/No
-->

### Testing

<!--
What kind of testing have these changes undergone?

None/Manual/Unit Tests
-->

---------

Co-authored-by: Paul Balaji <10051819+paulbalaji@users.noreply.github.com>

.changeset/sixty-plants-tie.md

@@ -0,0 +1,5 @@
+---
+'@hyperlane-xyz/sdk': patch
+---
+
+Added decimal consistency checks to the Token checker

typescript/infra/scripts/check/check-warp-deploy.ts

@@ -3,7 +3,7 @@ import { Gauge, Registry } from 'prom-client';
 
 import { warpConfigGetterMap } from '../../config/warp.js';
 import { submitMetrics } from '../../src/utils/metrics.js';
-import { Modules } from '../agent-utils.js';
+import { Modules, getWarpRouteIdsInteractive } from '../agent-utils.js';
 import { getEnvironmentConfig } from '../core-utils.js';
 
 import {
@@ -14,8 +14,15 @@ import {
 } from './check-utils.js';
 
 async function main() {
-  const { environment, asDeployer, chains, fork, context, pushMetrics } =
-    await getCheckWarpDeployArgs().argv;
+  const {
+    environment,
+    asDeployer,
+    chains,
+    fork,
+    context,
+    pushMetrics,
+    interactive,
+  } = await getCheckWarpDeployArgs().argv;
 
   const envConfig = getEnvironmentConfig(environment);
   // Get the multiprovider once to avoid recreating it for each warp route
@@ -29,8 +36,13 @@ async function main() {
 
   const failedWarpRoutesChecks: string[] = [];
 
+  let warpIdsToCheck = Object.keys(warpConfigGetterMap);
+  if (interactive) {
+    warpIdsToCheck = await getWarpRouteIdsInteractive();
+  }
+
   // TODO: consider retrying this if check throws an error
-  for (const warpRouteId of Object.keys(warpConfigGetterMap)) {
+  for (const warpRouteId of warpIdsToCheck) {
     console.log(`\nChecking warp route ${warpRouteId}...`);
     const warpModule = Modules.WARP;
 

typescript/sdk/src/deploy/HyperlaneAppChecker.ts

@@ -48,11 +48,7 @@ export abstract class HyperlaneAppChecker<
 
   async check(chainsToCheck?: ChainName[]): Promise<void[]> {
     // Get all EVM chains from config
-    const evmChains = Object.keys(this.configMap).filter(
-      (chain) =>
-        this.multiProvider.getChainMetadata(chain).protocol ===
-        ProtocolType.Ethereum,
-    );
+    const evmChains = this.getEvmChains();
 
     // Mark any EVM chains that are not deployed
     const appChains = this.app.chains();
@@ -82,6 +78,14 @@ export abstract class HyperlaneAppChecker<
     );
   }
 
+  getEvmChains(): ChainName[] {
+    return Object.keys(this.configMap).filter(
+      (chain) =>
+        this.multiProvider.getChainMetadata(chain).protocol ===
+        ProtocolType.Ethereum,
+    );
+  }
+
   addViolation(violation: CheckerViolation): void {
     if (violation.type === ViolationType.BytecodeMismatch) {
       rootLogger.warn({ violation }, `Found bytecode mismatch. Ignoring...`);

typescript/sdk/src/token/checker.ts

@@ -5,8 +5,9 @@ import {
   ERC20__factory,
   HypERC20Collateral,
   IXERC20Lockbox__factory,
+  TokenRouter,
 } from '@hyperlane-xyz/core';
-import { eqAddress } from '@hyperlane-xyz/utils';
+import { eqAddress, objMap } from '@hyperlane-xyz/utils';
 
 import { TokenMismatchViolation } from '../deploy/types.js';
 import { ProxiedRouterChecker } from '../router/ProxiedRouterChecker.js';
@@ -66,6 +67,30 @@ export class HypERC20Checker extends ProxiedRouterChecker<
 
     const expectedConfig = this.configMap[chain];
     const hypToken = this.app.router(this.app.getContracts(chain));
+
+    // Check all actual decimals are consistent
+    const actualChainDecimals = await this.getEvmActualDecimals();
+    this.checkDecimalConsistency(
+      chain,
+      hypToken,
+      actualChainDecimals,
+      'actual',
+      true,
+    );
+
+    // Check all config decimals are consistent as well
+    const configDecimals = objMap(
+      this.configMap,
+      (_chain, config) => config.decimals,
+    );
+    this.checkDecimalConsistency(
+      chain,
+      hypToken,
+      configDecimals,
+      'config',
+      false,
+    );
+
     if (isNativeConfig(expectedConfig)) {
       try {
         await this.multiProvider.estimateGas(chain, {
@@ -86,37 +111,119 @@ export class HypERC20Checker extends ProxiedRouterChecker<
     } else if (isSyntheticConfig(expectedConfig)) {
       await checkERC20(hypToken as unknown as ERC20, expectedConfig);
     } else if (isCollateralConfig(expectedConfig)) {
+      const collateralToken = await this.getCollateralToken(chain);
+      const actualToken = await (
+        hypToken as unknown as HypERC20Collateral
+      ).wrappedToken();
+      if (!eqAddress(collateralToken.address, actualToken)) {
+        const violation: TokenMismatchViolation = {
+          type: 'CollateralTokenMismatch',
+          chain,
+          expected: collateralToken.address,
+          actual: actualToken,
+          tokenAddress: hypToken.address,
+        };
+        this.addViolation(violation);
+      }
+    }
+  }
+
+  private cachedAllActualDecimals: Record<ChainName, number> | undefined =
+    undefined;
+
+  async getEvmActualDecimals(): Promise<Record<ChainName, number>> {
+    if (this.cachedAllActualDecimals) {
+      return this.cachedAllActualDecimals;
+    }
+    const entries = await Promise.all(
+      this.getEvmChains().map(async (chain) => {
+        const token = this.app.router(this.app.getContracts(chain));
+        return [chain, await this.getActualDecimals(chain, token)];
+      }),
+    );
+
+    this.cachedAllActualDecimals = Object.fromEntries(entries);
+
+    return this.cachedAllActualDecimals!;
+  }
+
+  async getActualDecimals(
+    chain: ChainName,
+    hypToken: TokenRouter,
+  ): Promise<number> {
+    const expectedConfig = this.configMap[chain];
+    let decimals: number | undefined = undefined;
+
+    if (isNativeConfig(expectedConfig)) {
+      decimals =
+        this.multiProvider.getChainMetadata(chain).nativeToken?.decimals;
+    } else if (isSyntheticConfig(expectedConfig)) {
+      decimals = await (hypToken as unknown as ERC20).decimals();
+    } else if (isCollateralConfig(expectedConfig)) {
+      const collateralToken = await this.getCollateralToken(chain);
+      decimals = await collateralToken.decimals();
+    }
+
+    if (decimals === undefined) {
+      throw new Error('Actual decimals not found');
+    }
+
+    return decimals;
+  }
+
+  async getCollateralToken(chain: ChainName): Promise<ERC20> {
+    const expectedConfig = this.configMap[chain];
+    let collateralToken: ERC20 | undefined = undefined;
+
+    if (isCollateralConfig(expectedConfig)) {
       const provider = this.multiProvider.getProvider(chain);
-      let collateralToken: ERC20;
 
       if (expectedConfig.type === TokenType.XERC20Lockbox) {
         const collateralTokenAddress = await IXERC20Lockbox__factory.connect(
           expectedConfig.token,
           provider,
         ).callStatic.ERC20();
-        collateralToken = await ERC20__factory.connect(
+        collateralToken = ERC20__factory.connect(
           collateralTokenAddress,
           provider,
         );
       } else {
-        collateralToken = await ERC20__factory.connect(
+        collateralToken = ERC20__factory.connect(
           expectedConfig.token,
           provider,
         );
       }
-      const actualToken = await (
-        hypToken as unknown as HypERC20Collateral
-      ).wrappedToken();
-      if (!eqAddress(collateralToken.address, actualToken)) {
-        const violation: TokenMismatchViolation = {
-          type: 'CollateralTokenMismatch',
-          chain,
-          expected: collateralToken.address,
-          actual: actualToken,
-          tokenAddress: hypToken.address,
-        };
-        this.addViolation(violation);
-      }
+    }
+    if (!collateralToken) {
+      throw new Error('Collateral token not found');
+    }
+    return collateralToken;
+  }
+
+  checkDecimalConsistency(
+    chain: ChainName,
+    hypToken: TokenRouter,
+    chainDecimals: Record<ChainName, number | undefined>,
+    decimalType: string,
+    nonEmpty: boolean,
+  ) {
+    const uniqueChainDecimals = new Set(
+      Object.values(chainDecimals).filter((decimals) => !!decimals),
+    );
+    if (
+      uniqueChainDecimals.size > 1 ||
+      (nonEmpty && uniqueChainDecimals.size === 0)
+    ) {
+      const violation: TokenMismatchViolation = {
+        type: 'TokenDecimalsMismatch',
+        chain,
+        expected: `${
+          nonEmpty ? 'non-empty and ' : ''
+        }consistent ${decimalType} decimals`,
+        actual: JSON.stringify(chainDecimals),
+        tokenAddress: hypToken.address,
+      };
+      this.addViolation(violation);
     }
   }
 }