Update eth_getCode to handle call to iHTS address (#629)

Update eth_getCode to handle call to iHTS address.
This will support eth dev tool calls to address(0x167)

- Add catch case for contract type and address(0x167)
- Add test cases

Signed-off-by: Nana Essilfie-Conduah <[email protected]>

Author: Nana-EC

packages/relay/src/lib/eth.ts

@@ -61,7 +61,8 @@ export class EthImpl implements Eth {
   static feeHistoryEmptyResponse = { baseFeePerGas: [], gasUsedRatio: [], reward: [], oldestBlock: EthImpl.zeroHex };
   static redirectBytecodePrefix = '6080604052348015600f57600080fd5b506000610167905077618dc65e';
   static redirectBytecodePostfix = '600052366000602037600080366018016008845af43d806000803e8160008114605857816000f35b816000fdfea2646970667358221220d8378feed472ba49a0005514ef7087017f707b45fb9bf56bb81bb93ff19a238b64736f6c634300080b0033';
-
+  static iHTSAddress = '0x0000000000000000000000000000000000000167';
+  static invalidEVMInstruction = '0xfe';
 
   // endpoint metric callerNames
   static ethCall = 'eth_call';
@@ -573,7 +574,14 @@ export class EthImpl implements Eth {
    */
   async getCode(address: string, blockNumber: string | null, requestId?: string) {
     const requestIdPrefix = formatRequestIdMessage(requestId);
-    // FIXME: This has to be reimplemented to get the data from the mirror node.
+    
+    // check for static precompile cases first before consulting nodes
+    // this also account for environments where system entitites were not yet exposed to the mirror node
+    if (address === EthImpl.iHTSAddress) {
+      this.logger.trace(`${requestIdPrefix} HTS precompile case, return ${EthImpl.invalidEVMInstruction} for byte code`);
+      return EthImpl.invalidEVMInstruction;
+    }
+
     this.logger.trace(`${requestIdPrefix} getCode(address=${address}, blockNumber=${blockNumber})`);
 
     const cachedLabel = `getCode.${address}.${blockNumber}`;
@@ -584,17 +592,20 @@ export class EthImpl implements Eth {
 
     try {
       const result = await this.mirrorNodeClient.resolveEntityType(address, requestId);
-
-      if (result && result?.type === constants.TYPE_TOKEN) {
+      if (result) {
+        if (result?.type === constants.TYPE_TOKEN) {
+          this.logger.trace(`${requestIdPrefix} Token redirect case, return redirectBytecode`);
           return EthImpl.redirectBytecodeAddressReplace(address);
+        }
+        else if (result?.type === constants.TYPE_CONTRACT) {
+          if (result?.entity.runtime_bytecode !== EthImpl.emptyHex) {
+              return result?.entity.runtime_bytecode;
+          }
+        }
       }
-      else if (result && result?.type === constants.TYPE_CONTRACT && result?.entity.runtime_bytecode !== EthImpl.emptyHex) {
-          return result?.entity.runtime_bytecode;
-      }
-      else{
-        const bytecode = await this.sdkClient.getContractByteCode(0, 0, address, EthImpl.ethGetCode, requestId);
-        return EthImpl.prepend0x(Buffer.from(bytecode).toString('hex'));
-      }
+      
+      const bytecode = await this.sdkClient.getContractByteCode(0, 0, address, EthImpl.ethGetCode, requestId);
+      return EthImpl.prepend0x(Buffer.from(bytecode).toString('hex'));
     } catch (e: any) {
       if(e instanceof SDKClientError) {
         // handle INVALID_CONTRACT_ID

packages/relay/tests/lib/eth.spec.ts

@@ -1281,6 +1281,14 @@ describe('Eth calls using MirrorNode', async function () {
       const res = await ethImpl.getCode(htsTokenAddress, null);
       expect(res).to.equal(redirectBytecode);
     });
+
+    it('should return the static bytecode for address(0x167) call', async () => {
+      mock.onGet(`contracts/${EthImpl.iHTSAddress}`).reply(200, defaultContract);
+      mock.onGet(`accounts/${EthImpl.iHTSAddress}`).reply(404, null);
+
+      const res = await ethImpl.getCode(EthImpl.iHTSAddress, null);
+      expect(res).to.equal(EthImpl.invalidEVMInstruction);
+    });
   });
 
   describe('eth_getLogs', async function () {